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#1
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
With the survivalist market as well as the DIYers who would build a
kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. That means no regens, no DC bull****, and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. I would use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. I would use a separate power supply and speaker for several reasons. I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. Any other comments? |
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#2
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
My guess is that the cost you would have to charge to recoup the time
and effort you put together in coming up with such a design would end up making such a set *much* more expensive than just going to a ham fest, buying a Hammarlund in good shape, and fixing it up. Or even paying someone else to fix it up. |
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#3
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Nov 11, 12:04*am, David Barts
wrote: My guess is that the cost you would have to charge to recoup the time and effort you put together in coming up with such a design would end up making such a set *much* more expensive than just going to a ham fest, buying a Hammarlund in good shape, and fixing it up. Or even paying someone else to fix it up. I already have a R-390, two Hammarlunds and a Racal....I wanted to manufacture something. Or at least think about it. |
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#4
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
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#5
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Nov 11, 8:57*am, "D. Peter Maus" wrote:
On 11/11/11 24:15 , wrote: On Nov 11, 12:04 am, David wrote: My guess is that the cost you would have to charge to recoup the time and effort you put together in coming up with such a design would end up making such a set *much* more expensive than just going to a ham fest, buying a Hammarlund in good shape, and fixing it up. Or even paying someone else to fix it up. * I already have a R-390, two Hammarlunds and a Racal....I wanted to manufacture something. Or at least think about it. * *Certainly worth thinking about. * *Maybe worth doing. But consider: * *Tubes are getting harder to come buy. Not that they can't be had. And after an EMP, they're likely to be as available as working SS devices. But there are inherent issues with Tubes. One is that they use a LOT of precious energy, that in a survival mode situation is best conserved for other applications, or longer listening. Another is that voltages are much higher than those that can be recovered after or during a crisis with ease. Low voltage, low current devices are going to be more desirable when energy is in short supply. * *But, more importantly, tube receivers aren't necessarily less prone to damage by EMP than SS receivers. In fact, there is empirical evidence to suggest that SS receivers can be made to survive an EMP where a tube receiver will not. * *Your best options, then, would include building a reasonably high performance receiver with readily available common parts, and take measures, such as a Faraday cage, and effective grounding/input protection measures, to render your station if not immune, then more resistant to stray or induced hostile voltages. * *Now, you have a practical, and manufacturable, product. -wrt- Faraday Cage : Old Metal {Steel} Garbage Can with a tight fitting Lid. -store-holding- + The Solid State AM/FM/SW Radio + Plenty of Batteries -or- Re-Chargeable Batteries and a Solar Charger -no-tubes-required- ~ RHF |
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#6
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On 11/11/2011 10:10 PM, RHF wrote:
... -wrt- Faraday Cage : Old Metal {Steel} Garbage Can with a tight fitting Lid. -store-holding- + The Solid State AM/FM/SW Radio + Plenty of Batteries -or- Re-Chargeable Batteries and a Solar Charger -no-tubes-required- ~ RHF . Satellites are withstanding these on an almost daily basis, for years, if not decades ... doesn't seem to be a real problem anymore ... however, laying hands to that technology might be a bit of a different story ... as, while one nation might wants its' own satellites hardened, it certainly doesn't want the enemies ... Regards, JS |
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#7
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Nov 11, 4:52*pm, wrote:
*With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. Most people who are into radio might think you are irrational, because good short wave reception with tubes has been done by major manufacturers of the past rather better than you can ever imagine to achieve, unless you have far greater intelligence than their leading chief designers wo passed lots of exams and universities and had passed the test of being jolly good fellows in the real world of private enterprise employment and marketing activities with the now mentioned Racal, and Hammlund, Hallicrafters et all, just to name a few. *That means no regens, no DC bull****, Regenerative boost I can understand, but "DC bull****" Such a term does not appear in any electronic books written prior to 1960 when tubed radio was regarded as the best mature technology for SW reception. and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). You must be dreamin'. Its not clear at all what you want. Do you wanna make a radio from scratch, or do ya wanna buy a kit made by some sucker who is likely to find he'll sell 2 kits over 10 years, and get a lousy price from YOU? If ya wanna build just ONE HF receiver for you only, then there's plenty of old books on making radios, just follow what you read in the books, de-bug all what you build, as all the manufacturers have done before you. What happens first though? Do you die in ten years leaving behind a mess to clean up and no working radio, or you get a working radio in 3 months, fairly well perfected, and live for 9 years and 9 mths to enjoy it? *It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. Ah, just WHO is going to clone anything from the past and make any money? use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. Your dreamin again. Its totally stupid to expect anyone might sell thousands of NEW made copies of 1960 SW radios sets without conducting a thorough market feasibility study. The COMPETION for what you propose now has become so overwhelming that nobody in their right mind would consider having say 10,000 new 6BA6, 6BE6 etc manufactured for a production run of thousands of SW sets. Before asking us silly questions, have you :- 1. Learnt all about SW tube radio, 2. Drawn up a probable, or provisional parts list, 3. spent weeks chasing quotes for parts exactly as yo specifiy, 4, Generally put in a whole lot of work so far without relying on any of us, who, IMHO, will conclude you are on a goose chase. *I would use a separate power supply and speaker for several reasons. Well of course, but you'll die when you work out the cost of production for your project is 100 times what people now pay for SW reception with a whole pile of features you'll probably not want to include. *I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. *The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. All those features have already been well sorted out by old makers. But there was a magazine called Electronics Australia which has now been swallowed up by 'Silicon Chip' but they have a CD with the old magazines monthly output from 1939 to 1965. http://shop.siliconchip.com.au/radio...ch-1965-1.html Perhaps within that magazine you'll find full articles about building good SW radios with tubes which were second to none. Hardly any of the parts used are now available, but hey, yo issa dreamer, and you'll just dream them all up. Reality is that you might spend years building such a set, at a glacial rate of 1 tube stage per 3 months. My bet is that of the maybe 200 blokes who attempted to build the radios which are so well described in the magazine, maybe 10 finished a set to a respectable standard. Magazines became viable, because dreamers bought them. Mostly do-little nerds as I recall. What's so rivettingly interesting about SW reception? What form of media entertainament is worth listening to on SW? What is available on SW which ain't available elsewhere, apart from a pile of noise, poor audio, whistles, fade outs, and old amateur blokes droning on and on about their latest hospital operations? New York police maybe? I regularly restore old radios. Last job was a 1947 Healing floor standing 5 band AM radio for the fashionable Bling-Blang generation of 1947, ie, my parents generation. It has a 6J8 mixer plus 6U7 IF, and is chockoblock with coils and special wafer switches but it does give remarkably good reception of Radio America of China Calling even in daytime, with a long wire antenna taken out to a nearby tree. Anyway, I put in about 130 hours fixin up the old banger, and the one section I didn't alter at all was the 3 band SW section. Not much alignment was needed to maximise performance. Local MW was changed to ferrite rod antenna replacing the horrible high impedance RF input tranny which worked fine before the present which is riddled with hum imposing itself on many incoming signals in the electro static portion of the electromagnetic waves. The ferrite rod reacts to the magnetic part of the incoming wave which is not affected by compact fluorescent lamps et all. But now we have local Digital Radio Broadcasting now all based on frequencies up around 250Mhz. The local Australian Broadcasting Commission, or ABC, has just begun trials here for broadcasting of all they have on MW, 2 stations, and all they have on FM, another 2 stations, on digital. Don't ask me how DAB works. I can't find any schematics of concise explanations. So, listeners who have loved their old tubed radio set because it carried the MW local stations now don't need to use their tubed set, and can access the old AM station program noise free and with full audio BW with hi-fi specs from their tiny little box sets for DAB. Now sometimes ppl with radios capable of SW might try surfing the bands, but now DAB is here ppl won't be able to surf these SW bands, but then who ever did ? There were 101 different ideas put forward for providing a decent tubed SW radio which never saw commercial development and production, such as the early synchrodyne. The superhet was deemed to be the best. Racal had 3 mixers, and was remarkably stable for an old banger but now with digtally generated oscillator F and all that chipery stuff and computer controlled stuff, stablity is far better now. Wanna copy a Yeasu? If I wanted to build a 6 band SW radio now I think I might have 6 j- fet RF amp stages well controlled by AVC, then 6 j-fets for oscillators, and thus not need a special made bandswitch, except some generic easy to buy wafer switch from Farnells with 6 positions. Mixer could be one of many options, maybe more than one, to minimise switching of the IF output. With such cheap small devices with high gm and low noise, the cost is far less than a complex switch and just two tubes to work on all bands. But all this is so easy to say, and such things are easier said than done, and succes relies on YOU. And there are very few ppl here who are heavily into farnarkling with HF radios, so there are not many brains here to be picked, or if you do try, you'll probably get 101 suggestions all requiring maybe years to perfect and after that you still can't equal the best old sets. I heard about a bloke who built a CD player using just generic opamps. It took so long...... Any other comments? But good luck with you quest. You'll definately need +60dB of that. Patrick Turner. |
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#8
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
Patrick Turner wrote:
But good luck with you quest. You'll definately need +60dB of that. Patrick, I too was going to write something like that, but you did far better than I could. The point that was buried in his original posting was that he is building an "EMP-PROOF" radio to sell to the survivalist market. Personally I think it is a fools errand, you can't build a modern radio similar to the high performing ones of the past at a cost anyone will pay, since in comparison, you can buy any one of the many old radios that will do, pay a professional to refurbish and align it, and buy several lifetimes worth of spare parts for far less. Not only that but radio collecting is a well known and liked hobby, nobody is going to take a second look at that old transoceanic on your shelf, but many would flip out seeing any firearm. If you are paranoid, you an even find stores in many places where you can buy a refurbished radio for cash and leave a fake name and address. Geoff. -- Geoffrey S. Mendelson, N3OWJ/4X1GM My high blood pressure medicine reduces my midichlorian count. :-( |
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#9
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
"Geoffrey S. Mendelson" wrote:
Patrick Turner wrote: But good luck with you quest. You'll definately need +60dB of that. Patrick, I too was going to write something like that, but you did far better than I could. The point that was buried in his original posting was that he is building an "EMP-PROOF" radio to sell to the survivalist market. SS sets are cheap and easily obtainable. Even a Happy Harry Home-owner type can cheaply build a small Faraday cage to keep one in, if anticipating an EMP. Personally I think it is a fools errand, you can't build a modern radio similar to the high performing ones of the past at a cost anyone will pay, since in comparison, you can buy any one of the many old radios that will do, pay a professional to refurbish and align it, and buy several lifetimes worth of spare parts for far less. You'd better invest in a generator and a supply of petrol, too... Not only that but radio collecting is a well known and liked hobby, nobody is going to take a second look at that old transoceanic on your shelf, but many would flip out seeing any firearm. Your friends are all hoplophobes? Why would anyone "flip out" when seeing a firearm? Hell, I have one in my pocket right now, and I can see two more from where I'm sitting. They don't look all that spooky to me. If you are paranoid, you an even find stores in many places where you can buy a refurbished radio for cash and leave a fake name and address. Huh? Where are you posting from? Why would anyone need to leave his name and address - fake or otherwise - when purchasing a radio? Got guns? Lord Valve American - so far |
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#10
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On 11/11/11 08:42 , Lord Valve wrote:
If you are paranoid, you an even find stores in many places where you can buy a refurbished radio for cash and leave a fake name and address. Huh? Where are you posting from? Why would anyone need to leave his name and address - fake or otherwise - when purchasing a radio? Because cash transactions are coming under the scrutiny of authority, today. Louisiana just became the most recent state to require identity of purchaser in a cash transaction or a ban on the cash transaction. Even a used purchase from a flea market or a garage sale. Other states are currently debating this provision. |
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#11
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 D. Peter Maus wrote: Where are you posting from? Why would anyone need to leave his name and address - fake or otherwise - when purchasing a radio? Because cash transactions are coming under the scrutiny of authority, today. Louisiana just became the most recent state to require identity of purchaser in a cash transaction or a ban on the cash transaction. Even a used purchase from a flea market or a garage sale. Other states are currently debating this provision. It's for the benefit of the *children*. Many contagious diseases are spread by filthy money and the Brothels just aren't sterilizing the bills like they used to. The Cocaine pushers are far better in this respect, as they get their clients to ingest any product left on the money. Only anti-American terrorists use cash for purchases. Next week I will be proposing a new 'Sterility' law which will require all canned good to be opened for examination before being placed on the store shelves. Then, the mandatory installation nation wide of surveillance cameras in the bathrooms of the Elderly. They fall a lot and the cameras would assure a swift response by medical teams. *SAFETY* is paramount. mike -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBAgAGBQJOvVymAAoJEGQ2h+1OL/Ac8BsH/jpsFzW2B4zZsToF1IijOYiU WvkC1ZMY0ccaL2VoxgXSeSwTSGw66XYB1DdEUHBTVDxoPH9Tp0 8HBHgDLP83t0Gi I5enxJIrMQhcjsZ9w9XP+sQxhxo0GTlySY5rGPXVshV5brxG1o scL8cfLLi/iMHU KrDSy7rjwmlTdghrpXUeUA2ikYTpQS2Yj82fF44Wl5F+D9yshX r7eLp1P7TIiqkQ C2M4bGSUxQesth2uwokN9ZT37pWAnKj4P8wT2iPHGHeI6A2LPA ybnugSpp5NVeKo P7gP9a8nDMVQdRbLGy9/tjpQDibk9isKB5vf1gARHbUCnoErZTFHH751oWgWurY= =0WgL -----END PGP SIGNATURE----- |
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#12
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Nov 12, 3:45*am, "D. Peter Maus" wrote:
On 11/11/11 08:42 , Lord Valve wrote: If you are paranoid, you an even find stores in many places where you can buy a refurbished radio for cash and leave a fake name and address. Huh? Where are you posting from? Why would anyone need to leave his name and address - fake or otherwise - when purchasing a radio? * *Because cash transactions are coming under the scrutiny of authority, today. Louisiana just became the most recent state to require identity of purchaser in a cash transaction or a ban on the cash transaction. Even a used purchase from a flea market or a garage sale. * *Other states are currently debating this provision. How about that. I guess the Taxation and Police authorities might like to know how and where ppl spend their cash. But I heard that since 911, hundreds of huge and mainly hidden buildings housing about 2 million workers across the USA have been quietly built and operate to filter all email traffic and phone traffic to detect terrorists and possibly anyone other selectable target, like people trading in OLD STUFF like old radios which consume the same amount of electricity to run an air con unit, or 500 i-pods. These spying centers suck in digital data like huge vacuum cleaners, then apply a filter for key words. One wonders if such centers could detect the next intended school shooting or Oklahoma Bombing. The so called BLACK ECONOMY, ie, the flow of cash which can't be traced and hence isn't taxed is one of the big reasons to try to outlaw cash, and thus have everyone pay the transaction cost to a 3rd party by means of the credit card. But here in Oz, cash is still widely used, and everyone I know does not need to be told to bring cash when paying me peanut wages for radio repairs. I explain to ppl that average wages are 60 grand a year now, ie, $1,300 a week for the 46 weeks out of 52 ppl actually work, ie, $32.50c per hour of 40 hrs a week. (( Ppl get to "administer" this amount, then have to pay $10 income tax and maybe 25 other various bribes to banks for mortage payments and GST, and company profits etc, etc, etc, before keeping $3.25 to buy bananas to give the banana farmer a similar amount via the system of banana distribution so he ends up with 10c per banana. Its all far more complex than a company boss or union rep is willing to describe )). But a radio might take 120 hrs to fix right, and maybe I get $600, after giving them a discount of $3,300 off the wages of $3,900 which should be paid for 120 hours of work. Cash will be around for awhile yet, but in 20 years perhaps goverments will try to save money by not printing it. I'll be dead as the species of cash becomes extinct like the lions, tigers, and elephants, and thousands of lesser known species. Trouble may come if a government values a radio repair transaction as being worth say $3,900 instead of $600, and taxes people on the same rate as those earning average weekly earnings to discourage anyone offering discounts to compete, or to survive. All sorts of BS is possible, but so far, afaik, cash is still extremely popular here. But in 1983, if someone wanted to extend their house, all work valued above $10,000 had to be "declared" to prevent ppl hiding un-seen cash income in the form of house improvements. Guess what. Ppl just did little bits of improvements at a time and still managed to get their house extensions approved by the govt authorities. Bundles of notes went out of one pocket and into another one. But in Greece, there is mastery of the cash economy, and they have many other devious ways of keeping NOSY PARKER GOVT out of business, and as a result, you see the mess Greece is in. Two sides to every story. Maybe another Great Depression might just happen. The Financial System BEAST of the world survives because other ppl have a hand in YOUR pocket whether you like it or not. The Beast extracts a steady trickle of bucks to make credit flow. The trickle is like food, a small percentage of body weight needs to be consumed by the Beast each day to survive and if the trickle feed stops, the Beast gets very sick indeed, thus giving everyone the ****s in a big way. Departments of taxation and Criminal control departments of governments around the world are part of the Beast. Beastly health is mostly desirable, but colly wobbles can now be heard. And there is a gigantic building here worth a billion or two being built at high speed for ASIO, the Oz branch of CIA equivalent, right here in town. Maybe it'll have about 3,000 ppl employed to keep a watch on what everyone else is doing, saying, typing, and sending, and its only "one small step" to knowing what everyone is thinking, and a "giant leap for mankind" to control thinking. From what I see, everyone wants a cheap deal and they don't care about your wages, just their own. Ppl don't care about the environment of anyone or anything living more than 5km away from themselves. Most ppl don't really mind being spied on. And many will happily spy on everyone else. Its going on, and people ain't rioting in the streets about it. Patrick Turner. |
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#13
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
Wow, I lit a loaded fart off here, didn't I?
First, I said use a Hallicrafters band switch and an Eddystone dial because there's probably a market for those with old Hallicrafterses with bad bandswitches and with regen builders respectively. The problem with the Hallicrafters band switch replacement market is that there are so many DIFFERENT ones, if they were all the same they'd be reproduced. Remember rotary switches are modular, to a degree, the company that makes them builds them out of mostly off the shelf parts, and in fact you CAN get new ones built, but the problem is that they cost more than the value of most hallicrafters radios, since they have to put them together as one offs. 500 units takes the price from $400 to $25-50 each. At twenty five bucks a shot you could sell a couple hundred in six months....IF you had a unit that went into enough popular radios. Eddystone dials are a similar thing. The market has to be a mix of nostalgia and survival mentality. Yes, a solid state radio can be made EMP proof, or highly resistant, but it takes some doing. As far as power in such a situation....In the old days they used car batteries for heater voltages and a stack of dry cells, a dynamotor or a vibra-pack for B+.. Look carefully at the old Collins and National sets. They developed it to something of a fine art. As an aside, any "survivalist" with half a brain has buried a couple of solid state complete radios as well as a pile of surplus semiconductors useful post-Blast in old ammo cans. A stash of common bipolar and FETs, silicon diodes, common chips for radios and whatnot, buried under ground could be more valuable than gold and at a hell of a lot lower current acquisition price today. Some discussion on which types would be interesting. I don't consider myself a survivalist but I have a couple of guns and some ammo buried along with a couple of full jerry cans of 100LL avgas (it doesn't go bad) and some electronic stuff, plus some garage sale Craftsman tools, some spools of wire from a motor shop (short ends), and a couple things I won't mention. Better safe than sorry I figure. |
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#14
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
Australia got stupid with its gun laws when they let the 'sheilas'
vote. We got Prohibition under similar circumstances. Female suffrage was a great idea...NOT! |
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#15
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On 11/15/11 19:05 , flipper wrote:
On Fri, 11 Nov 2011 10:45:09 -0600, "D. Peter Maus" wrote: On 11/11/11 08:42 , Lord Valve wrote: If you are paranoid, you an even find stores in many places where you can buy a refurbished radio for cash and leave a fake name and address. Huh? Where are you posting from? Why would anyone need to leave his name and address - fake or otherwise - when purchasing a radio? Because cash transactions are coming under the scrutiny of authority, today. Louisiana just became the most recent state to require identity of purchaser in a cash transaction or a ban on the cash transaction. Even a used purchase from a flea market or a garage sale. You need to be more cautious and critical of Internet and media hype. And you need to make sure you're not talking to someone getting his information first hand from the legislators voting on the bill. It does not apply to non profits, flea markets, garage sales, persons solely engaged in the business of buying, selling, trading in, or otherwise acquiring or disposing of motor vehicles and used parts of motor vehicles, or wreckers or dismantlers of motor vehicles, dealers in coins and currency, dealers in antiques, gun and knife shows or other trade and hobby shows, and, well, anyone who isn't a "secondhand dealer" Actually, these are specifically what the law is intended to address. |
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#16
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Building a new shortwave tube radio
On Nov 11, 11:29*pm, "Geoffrey S. Mendelson"
wrote: Patrick Turner wrote: But good luck with you quest. You'll definately need +60dB of that. Patrick, I too was going to write something like that, but you did far better than I could. The point that was buried in his original posting was that he is building an "EMP-PROOF" radio to sell to the survivalist market. Oh, I didn't think of that. If WW3 breaks out, all arses will have departed, because on hearing about the beginning of WW3 off the Internet, everyone will bend down to kiss their arse goodbye, and arses will depart, bye-bye, and no need for toilets or food any more. But "survivalist" resonated exuberantly in my mind because I'm 64, and the foppish Beatles used to sing a song "will ya still lerve me when I'm 64?". I'm 64. I know the answer, forbidden to be sung about by anyone, and its NO, no one at all will lerve ya when your'e 64, so that means all that's left is survival against a rotten horrible marauding mob of young upstarts hell bent on invading and pillaging and burying alive all that my father's generation established, and they all **** a lot while I'm not allowed to 'av one, well, not for free, and mean while this horrible lot are decimating the remaining species across the planet, and all trying to build absurdly large mansionettes, while all sending huge quantites of CO2 skywards which will ruin the weather, and exacerbate their self generated future difficulties. One "survivavlist" I know had two sound systems I serviced, a Quad-II with early Whardale LS, and a Leak system. Once inside the door of his house, one entered the lounge-room, and it was all exactly as it was in 1955, with a 1956 newspaper on the coffee table screaming headlines "SUEZ BOMBED". 1956 was a time when the rot of modernity really got a toe past the front door of most ppl, and rock and roll was seen as just as bad as WW3. So, this survivalist guy just saw no reason to mentally proceed past 1956. He worked his way up to being chief conserverator at the Australian Sound and Film Archives where much of the audio-visual media of the past ends up to be converted to digital files for future generations to enjoy, and for old blokes to gloat over. I humbly seek approval and aknowledgement that I know what "survivalist" means, and I can also back up mu claim because I know now that the older I get, the betta I was, and I have the recently created medical and dental records to prove it. Personally I think it is a fools errand, you can't build a modern radio similar to the high performing ones of the past at a cost anyone will pay, since in comparison, you can buy any one of the many old radios that will do, pay a professional to refurbish and align it, and buy several lifetimes worth of spare parts for far less. Professionals who know about old Racals and so on are just about all dead now. But to copy a Racal so you could provide a kit would be financial suicide. Not only that but radio collecting is a well known and liked hobby, nobody is going to take a second look at that old transoceanic on your shelf, but many would flip out seeing any firearm. If you are paranoid, you an even find stores in many places where you can buy a refurbished radio for cash and leave a fake name and address. Well, lotsa Mr Para Noids getting around on the Internet; they all broadcast their ideas, using a false nickname, and wouldn't dare use the name given to them by their parents. So paranoidism isn't any big deal. Bet ya don't go out to night clubs at 2AM any more to hunt for hot crumpet. Too many arsoles will happily mug you. Paranoidism prevents you wandering like a lost old dog than the young bitches will laugh at. Survivalism has you staying at home. But bicycles are safe during the day. Patrick Turner. Geoff. -- Geoffrey S. Mendelson, *N3OWJ/4X1GM My high blood pressure medicine reduces my midichlorian count. :-( |
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#17
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Building a new shortwave tube radio
wrote in message ... With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. I can't imagine that any rational survivalist would waste power running tubed electronics. I guess you could hype the EMP issue, but even that can be handled better with SS. |
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#18
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Building a new shortwave tube radio
On Thu, 10 Nov 2011 21:52:48 -0800, rrusston wrote:
the bandswitch and coils from some Hallicrafters or Hammarlund set, Anyone who'd use the old Halli bandswitch has never had to fix a Halli bandswitch. The trouble with valve radios is they use lots of electricity. |
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#19
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Building a new shortwave tube radio
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#20
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Building a new shortwave tube radio
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#21
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Building a new shortwave tube radio
On Nov 12, 5:07*am, John Smith wrote:
On 11/10/2011 9:52 PM, wrote: * With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. * That means no regens, no DC bull****, and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). * It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. I would use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. * I would use a separate power supply and speaker for several reasons.. * I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. * The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. Any other comments? Yeah, why would anyone build a survival set whose filaments would burn much more power than a VERY high end transistor set? *You plan on hauling around sq yards of solar cells to power that rig? Regards, JS- Hide quoted text - - Show quoted text - The OP may not be hauling mobile tube stuff anywhere. But best SW reception is at night, when the sun don't shine, and the wind hardly blows much. But many ppl here have bought solar photo-voltaic systems for the house roof and they sell the excess power back to the main supplier of the Grid. This pays for the electricity used at other times. But authorities worked out this payment for locally generated power was a subsidy paid by those without solar, and a loss and big ****fights over money occurred soon after solar panel uptake went way over what was expected. Encouraging solar was regarded as part of the "Being seen to be doing something Green and Good" and therefore getting votes, while in reality increasing the cost of electricity, and making SFA difference to overall CO2 emissions. So pay back rates ahve plummeted, and solar companies have gone broke, as only the rich can afford to pay for solar panels, let alone the batteries needed for use of power at night. Country dwellers can get by on low power of solar and batteries if they are careful and have low power everything, use batteries, cook on wood fire, heat water with wood stove, use gas maybe etc, but tube audio or radio is about out of the question, unless you use the low filament current tubes meant for portable radios so popular between 1935 and 1955. They would be very easy to rum from a few batteries, only 8 x 12V car batteries are needed for a B+ of 90Vdc, and its simple to arrange low voltage DC batteries for directly heated cathodes which use very little current. But such "portable tubes" are not being made now. Plenty of good solid state SW radios operating on very low power are to be had. Ppl can then focus on antennas if they want good reception. The receiver performance is basically solved, but after WW3, if you survive, a good antenna to pick up other survivors transmitting with low power might be handy. This assumes WW3 will send the world back to about where it was in 1925, with maybe 2 billion survivors with accelerated death rates, and ever declining technical production ability for non essentials. Essentials like ammunition, bows and arrows will be manufactured. Patrick Turner. |
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#22
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Building a new shortwave tube radio
Hate to say this but you are doomed to fail from the start.
Why? There are PILES of tube type SW receivers available now FAR cheaper than you could build one. Hey, I get it. It'd be a fun project. I've thought about doing something like this myself but seriously consider the cost. Not just of the parts but the time involved in the design, marketing, and *liability insurance*. Bet you didn't think about that one! Steve |
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#23
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Building a new shortwave tube radio
On Nov 21, 10:07*am, "Steve" wrote:
Hate to say this but you are doomed to fail from the start. Why? There are PILES of tube type SW receivers available now FAR cheaper than you could build one. Hey, I get it. It'd be a fun project. I've thought about doing something like this myself but seriously consider the cost. Not just of the parts but the time involved in the design, marketing, and *liability insurance*. Bet you didn't think about that one! * * * * * * * * * * * * * * * * * * * * * * * * * Steve Liability insurance is tattooing "SUE ME" on your butt cheeks. The general aviation industry nearly put ITSELF out of business by answering every lawsuit with....you guessed it...more liability insurance. The scuba diving industry instituted a certification program and convinced all the attorneys that if a noncertified diver killed himself by the traditional methods (embolisms or drowning) juries would just laugh at them. Sport diving equipment companies do not carry PL coverage except for tank explosions out of the water. No one sues them for diving accidents. If they did they'd get the keys to an empty warehouse. The sport diving companies are all turnips, judgementproof. The COMMERCIAL diving companies are very funny as to whom they will sell. The few eccentric hobby hard hat guys will attest to this. You can buy scuba equipment for a lot less today than thirty years ago, in adjusted dollars. Airplanes have gone up by a factor of three or four or five. Buy legal insurance, and incorporate yourself so that you can not be construed to have a personal holding corporation. But never buy PL insurance or if you do have it strictly limited to a circumstance which is incidental. As to the piles of existing sets, yeah, there are-most are in bad need of restoration. And most of them weren't worth a **** new. The few good ones are carefully husbanded. The surplus Collinses and Hammarlunds are about gone. |
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#24
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Building a new shortwave tube radio
On Nov 11, 5:52*am, wrote:
*With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. *That means no regens, no DC bull****, and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). *It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. I would use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. *I would use a separate power supply and speaker for several reasons. *I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. *The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. Any other comments? The need for testgear to align the IF will wipe out 99.9% of any potential market. As pointed out, its going to be far too expensive. If you took that to heart and tried to make something far cheaper, regeneration, although a definite compromise, is a dead sure way to cut costs a lot, and has angelic AGC performance. I recall a simple 3 valve 1930s regen set giving rock steady audio on a signal even an exceptionally complex modern dx set couldnt stabilise. NT |
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#25
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Building a new shortwave tube radio
On Nov 25, 6:44*pm, NT wrote:
On Nov 11, 5:52*am, wrote: *With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. *That means no regens, no DC bull****, and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). *It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. I would use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. *I would use a separate power supply and speaker for several reasons. *I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. *The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. Any other comments? The need for testgear to align the IF will wipe out 99.9% of any potential market. As pointed out, its going to be far too expensive. If you took that to heart and tried to make something far cheaper, regeneration, although a definite compromise, is a dead sure way to cut costs a lot, and has angelic AGC performance. I recall a simple 3 valve 1930s regen set giving rock steady audio on a signal even an exceptionally complex modern dx set couldnt stabilise. NT One of the very reasons I DON"T like regens and direct conversions is "No Alignment". You need to have some kind of sig gen and preferably a scope. That's a feature, not a bug. Any hamfest in the US will net a working scope for a twenty dollar bill and probably a usable RF generator for a similar sum. The guitar amp ****s will part them out for the tubes and throw them in the dumpster often as not. In a pinch a grid dipper and a solid state RF probe attached to a DMM will work. |
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#26
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Building a new shortwave tube radio
On Nov 26, 5:54*am, wrote:
On Nov 25, 6:44*pm, NT wrote: On Nov 11, 5:52*am, wrote: *With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. *That means no regens, no DC bull****, and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). *It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. I would use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. *I would use a separate power supply and speaker for several reasons. *I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. *The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. Any other comments? The need for testgear to align the IF will wipe out 99.9% of any potential market. As pointed out, its going to be far too expensive. If you took that to heart and tried to make something far cheaper, regeneration, although a definite compromise, is a dead sure way to cut costs a lot, and has angelic AGC performance. I recall a simple 3 valve 1930s regen set giving rock steady audio on a signal even an exceptionally complex modern dx set couldnt stabilise. NT *One of the very reasons I DON"T like regens and direct conversions is "No Alignment". *You need to have some kind of sig gen and preferably a scope. That's a feature, not a bug. *Any hamfest in the US will net a working scope for a twenty dollar bill and probably a usable RF generator for a similar sum. The guitar amp ****s will part them out for the tubes and throw them in the dumpster often as not. *In a pinch a grid dipper and a solid state RF probe attached to a DMM will work. If I were designing such a product, I'd do everything in my power to avoid end user alignment with testgear, for one very simple reason: it wipes out 99.9% of your potential customers, its business suicide. Perhaps one could use resonators instead of LCs, if you dont like the interstation garbage of agced reaction. NT |
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#27
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Building a new shortwave tube radio
On Nov 27, 4:08*pm, NT wrote:
On Nov 26, 5:54*am, wrote: On Nov 25, 6:44*pm, NT wrote: On Nov 11, 5:52*am, wrote: *With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. *That means no regens, no DC bull****, and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). *It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. I would use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. *I would use a separate power supply and speaker for several reasons. *I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. *The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. Any other comments? The need for testgear to align the IF will wipe out 99.9% of any potential market. As pointed out, its going to be far too expensive. If you took that to heart and tried to make something far cheaper, regeneration, although a definite compromise, is a dead sure way to cut costs a lot, and has angelic AGC performance. I recall a simple 3 valve 1930s regen set giving rock steady audio on a signal even an exceptionally complex modern dx set couldnt stabilise. NT *One of the very reasons I DON"T like regens and direct conversions is "No Alignment". *You need to have some kind of sig gen and preferably a scope. That's a feature, not a bug. *Any hamfest in the US will net a working scope for a twenty dollar bill and probably a usable RF generator for a similar sum. The guitar amp ****s will part them out for the tubes and throw them in the dumpster often as not. *In a pinch a grid dipper and a solid state RF probe attached to a DMM will work. If I were designing such a product, I'd do everything in my power to avoid end user alignment with testgear, for one very simple reason: it wipes out 99.9% of your potential customers, its business suicide. Perhaps one could use resonators instead of LCs, if you dont like the interstation garbage of agced reaction. NT Of course a valve radio is business suicide to begin with, performance per dollar has come a long way since the valve era. Number of valve radios currently on the market is zero, so no-one has managed to make them compete with 30cent ICs and 2cent transistors. NT |
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#28
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Building a new shortwave tube radio
On 11/27/11 10:18 , NT wrote:
On Nov 27, 4:08 pm, wrote: On Nov 26, 5:54 am, wrote: On Nov 25, 6:44 pm, wrote: On Nov 11, 5:52 am, wrote: With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. That means no regens, no DC bull****, and no plug in coils. It must have production grade RF and IF coils, a bandswitch, and require alignment. If sold as a kit the builder will need a RF generator and a scope (or a spec an or CSM with a track gen). It should use off the shelf parts even if those shelves are bare, as it is better to copy an existing item than design from scratch. I would clone the Eddystone dial mechanism and the bandswitch and coils from some Hallicrafters or Hammarlund set, they could be sold as desperately needed replacement spares for the old sets too. I would use a seeing eye tube mounted in a hole in the dial as opposed to a meter movement, again, getting a run of new tubes made is possible if you are buying several thousand. There are some surplus that could be used if really needed too. I would use a separate power supply and speaker for several reasons. I would have the radio take in B+ and heater voltage and put out 600 ohm +4 audio. A regular supply could be used at home or car battery and a switchmode brick for B+. A headphone jack would be supplied off this tube. The set should cover 500 kHz to 30 MHz, AM, SSB and CW, with a product detector of course. A 455 kHz IF is needed so as to use common mechanical or crystal filters, which are optional. There should also be a 455 kHz IF out for an external synchronous detector. Any other comments? The need for testgear to align the IF will wipe out 99.9% of any potential market. As pointed out, its going to be far too expensive. If you took that to heart and tried to make something far cheaper, regeneration, although a definite compromise, is a dead sure way to cut costs a lot, and has angelic AGC performance. I recall a simple 3 valve 1930s regen set giving rock steady audio on a signal even an exceptionally complex modern dx set couldnt stabilise. NT One of the very reasons I DON"T like regens and direct conversions is "No Alignment". You need to have some kind of sig gen and preferably a scope. That's a feature, not a bug. Any hamfest in the US will net a working scope for a twenty dollar bill and probably a usable RF generator for a similar sum. The guitar amp ****s will part them out for the tubes and throw them in the dumpster often as not. In a pinch a grid dipper and a solid state RF probe attached to a DMM will work. If I were designing such a product, I'd do everything in my power to avoid end user alignment with testgear, for one very simple reason: it wipes out 99.9% of your potential customers, its business suicide. Perhaps one could use resonators instead of LCs, if you dont like the interstation garbage of agced reaction. NT Of course a valve radio is business suicide to begin with, performance per dollar has come a long way since the valve era. Number of valve radios currently on the market is zero, so no-one has managed to make them compete with 30cent ICs and 2cent transistors. NT Valves have a place in audio, for the truly faithful. But then, audio only requires a few valve types, frequencies are easily managed, and circuitry remains stable for much longer periods of use. Whereas radio applications require more sophisticated valve construction, and significantly different valve types for given applications, to accomodate frequencies that stretch from 10X to 100000X audio frequencies. What's comforting in radio with valve technology, is the general sense that the technology itself is accessible. And widely understood to be more forgiving. That valves may be removed, tested, and replaced by the techologically limited, and operated under conditions that would destroy solid state. Whereas, SS receivers, self service requires a much higher level of skill, with a much lower threshold of abuse. For those with limited technological experience, this can be daunting. Especially, as in the case of this receiver, during an emergency, where supply lines are uncertain, and technical support is nonexistent. I can see where the OP is coming from. Build an accessible receiver that's fairly forgiving to extremes in noise, signal levels, voltage, and hostile events, and you'd have a generally useful rig for the general population in an emergency. It's a nice thought. But as has been pointed out here multiple times, SS technology in a proper design has proven more resistant to EMP than generally believed, operating voltages are easier to generate, and manage, power requirements are lower, and performace of the technology is dramatically improved since the days of valve receivers. All at a fraction of the cost. And in an emergency, valve supplies will be just as short as SS components. All of which points to the fact that a well designed kit radio for use in emergencies would be more like the Ten-Tec 1254, than it would be like a Hallicrafters S-40. And the Ten-Tec 1254 is a kit, costs $200, and requires no user alignment, but offers significant performance across the spectrum from LF through HF. In a package that's available now. |
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#29
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Building a new shortwave tube radio
NT View profile More options Nov 27, 10:08 am On Nov 26, 5:54 am, wrote: - Show quoted text - If I were designing such a product, I'd do everything in my power to avoid end user alignment with testgear, for one very simple reason: it wipes out 99.9% of your potential customers, its business suicide. Perhaps one could use resonators instead of LCs, if you dont like the interstation garbage of agced reaction. NT Reply Reply to author Forward Report spam NT View profile More options Nov 27, 10:18 am On Nov 27, 4:08 pm, NT wrote: - Show quoted text - Of course a valve radio is business suicide to begin with, performance per dollar has come a long way since the valve era. Number of valve radios currently on the market is zero, so no-one has managed to make them compete with 30cent ICs and 2cent transistors. I intend to set the expectation that you must have a bench with a certain amount of basic test equipment and a proper soldering station to do this. If you will or can not do this a different hobby is for you. Large numbers of Heathkits were built by people with NO skills, but larger numbers got half finished and thrown in the dumpster or taken to a shop and a large sum was paid to have them pro built to save face. I knew a TV shop owner who had a policy: He'd fix ANY Heathkit but he charged a one time fee equal to the kit price. Otherwise he would not even look at them. Heathkits did a poor job of teaching technicianship precisely because they were secretaryworthy. Bauer built radio broadcasting gear the same way. A secretary could build them and at NAB one year one did. I am not looking at a BIG market. |
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#30
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Building a new shortwave tube radio
On Sun, 27 Nov 2011, NT wrote:
If I were designing such a product, I'd do everything in my power to avoid end user alignment with testgear, for one very simple reason: it wipes out 99.9% of your potential customers, its business suicide. Perhaps one could use resonators instead of LCs, if you dont like the interstation garbage of agced reaction. And Heathkit is the model for that. They'd prealign tuned circuits, they'd have certain stages as preassembled modules, they'd build some relevant test equipment into the equipment (like those tv sets with some sort of metering in the back). One I always liked was a scanner, they included some parts to make up a 10.7MHz oscillator and mixer. The oscillator would provide the signal to align the IF strip, and then you'd mix the local oscillator with this outboard oscillator/mixer to get a signal on the signal frequency, to align the front end. Heathkit of course did design for the beginner, I gather once they had the instructions together they found people who had never put a kit together to follow the instructions so they could make sure they made sense (and if followed properly, would result in a working piece of equipment). Despite the fuss about Heathkit being for the hobbyist, they always had taht color tv set, that musical organ, that boonie bike, that were aimed at people who just wanted something cheaper, and were willing to put some time into it. But that's why Heathkit shut down the kits, with time the sorts of things their was interest in got so complicated (and parts so small) that it was no longer cheap to come up with the instructions, pack the kit compared to just building it at the factory. As for ceramic resonators, I think that is a key point. Design is the overall results. When companies put in ceramic resonators in everyday radios, they did away with a large part of the alignment, so even if the resonators were more expensive than IF transformers (I don't know) the reduction in alignment time was still significant. As I pointed out, move to a higher IF, you may pay more for an IF filter, but you can do away with the need to gang the front end tuning with the local oscillator, which simplifies things mechanically but also gets rid fo a lot of troublesome alignment. It's relatively easy to get two stages of front end tuning to align together, just go for a peak, but ganging it with a local oscillator is more complicated. The superhet alone is a concept that complicates something to make other things easier. Make things more complicated, the mixer and oscillator, and you dont' have to fuss with multiple stages on the RF frequency. Sometimes the "simplest" solution ends up with more work than the more complicated one. Michael |
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#31
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Building a new shortwave tube radio
On Nov 27, 11:16*am, Michael Black wrote:
On Sun, 27 Nov 2011, NT wrote: If I were designing such a product, I'd do everything in my power to avoid end user alignment with testgear, for one very simple reason: it wipes out 99.9% of your potential customers, its business suicide. Perhaps one could use resonators instead of LCs, if you dont like the interstation garbage of agced reaction. And Heathkit is the model for that. *They'd prealign tuned circuits, they'd have certain stages as preassembled modules, they'd build some relevant test equipment into the equipment (like those tv sets with some sort of metering in the back). One I always liked was a scanner, they included some parts to make up a 10.7MHz oscillator and mixer. *The oscillator would provide the signal to align the IF strip, and then you'd mix the local oscillator with this outboard oscillator/mixer to get a signal on the signal frequency, to align the front end. Heathkit of course did design for the beginner, I gather once they had the instructions together they found people who had never put a kit together to follow the instructions so they could make sure they made sense (and if followed properly, would result in a working piece of equipment). Despite the fuss about Heathkit being for the hobbyist, they always had taht color tv set, that musical organ, that boonie bike, that were aimed at people who just wanted something cheaper, and were willing to put some time into it. *But that's why Heathkit shut down the kits, with time the sorts of things their was interest in got so complicated (and parts so small) that it was no longer cheap to come up with the instructions, pack the kit compared to just building it at the factory. Heathkit offered factory wired as well as kit equipment in many cases. But even the kits were more expensive than good used competitive equipment and sometimes more than respectable factory built. The Japanese were part of the problem because they made it their business to acquire market share at the expense of profit. The Japanese in their salad days were content to take losses no American competitor would for market share, because they thought long term. American companies quit thinking long term in the mid-70s because MBA thinking and stock market valuation was everything to the CEO. The Japanese were racially conscious, nationalistic, and group future driven and have always had a "co-opetitive" rather than dog-eat-dog mentality. What has sidelined Japan is the acceptance of American business theory. In Amateur Radio products, Japanese companies sold equipment at cost or lower until there was no more American competition. In fact, they still sell them at prices amazingly low for their feature sets and costs of development. That is because they figure the American ham who is appliance operating instead of building is not learning and being the competitive future. Conspiracy theory? No, experience. My father worked for a Motorola plant in the Midwest for decades. When a certain board member died, Mother M sold the plant and product line to Matsu****a _for less than the real estate was worth_. I don't blame Matsu****a for buying it and shutting it down, even though they swore they would not do so. It was a competitor they didn't need. But the people of the town, although many are very stupid, still needed those jobs. I don't blame them: they were acting rationally. It is we who acted irrationally in allowing such a deal to go through. Ford or GM would have been happy to buy up Japanese car plants in the 70s and do likewise, but the Japanese would not allow it. No sane nation would. Sorry to get into politics. Another fault with Heathkit equipment was often that mechanically they weren't very good. Their audio amps in the tube era were fine, because no mechanicals are needed there. In ham equipment they needed that and didn't have it. Collins and Drake were much much better. Yes, they cost more, but by the time I was in high school there were good buys in older Collins and Drake equipment because the first S/Line and 4 line buyers were going /SK already. Another reason American companies abandoned ham and shortwave radio was that government defense contracts spoiled most companies that got them. Once spoiled they were like fat lazy schoolkids, and discipline was not forthcoming. Collins was always an avionics company, and into commercial broadcast as well. Art Collins kept them in the ham business but when he died they ditched it as fast as possible. |
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#32
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Building a new shortwave tube radio
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#33
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Building a new shortwave tube radio
On Nov 27, 7:27*pm, John Smith wrote:
On 11/10/2011 9:52 PM, wrote: * With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. ... Any other comments? As I once pointed out, long ago, now, in an amateur group, what needs to be done is to build a radio equiv to how PCs are now done. First you would have a generic case, these could be made by anyone, in any design. *The would provide the user with an abundance of choice in the looks of the rig. Next, each section of the radio would simply be a plug in card, to a "mother board." *You would have an rf section, which could cover any and all bands, depending on construction, it would simple plug into one of the slots on the motherboard. *Audio, rf, filter, conversion, etc., etc.. could be done this way. You would have a basic set of all sections, and could expand, or upgrade as you would have -- or as becomes available. It would change the face of radio, SW radios would become as numerous as PCs -- well, almost. Most any small manufacturer could enter the market, and provide a case, rf section, audio section, etc. -- and expand from there, if they choose. I simply can't get enough interest ... but the radio could be just am, am fm, am-fm-sw, am-fm-sw-vhf, am-fm-sw-vhf-uhf, am-fm-sw-vhf-uhf-shf, or any possible combination wanted ... this is an idea whose obvious advantage, for consumers, is simply screaming out for production! Later, if one wished, he could just buy a larger standard case, move his receiver components over, buy a larger power supply, and drop in the appropriate transmitting section(s.) We simply wait for the radio to leave the age of the horse and buggy ... Regards, JS But.... 99% of radio buyers have little idea what features they want, and the very slow change in feature sets of each module are in most cases of close to zero interest to end users. Plus radios seldom become obsolete - even 1920s sets are still usable, for the few of us that wish to. Unit radio did of course exist in the early 20s, when radio technology really was changing fast, and it made a significant difference. Come the 30s it was gone though, even though the technology was still changing fast. End users didn't vote for it. A slightly similar approach was also tried in tv in the 70s, with lots of small pcbs that could each be replaced affordably if it ever failed. But ultimately buyers just wanted the cheapest, not to pay for later repairability. Does anyone other than John think there's commercial mileage in modular radio now? NT |
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#34
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Fri, 2 Dec 2011 17:48:46 -0800 (PST), NT
wrote: On Nov 27, 7:27*pm, John Smith wrote: On 11/10/2011 9:52 PM, wrote: * With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. ... Any other comments? As I once pointed out, long ago, now, in an amateur group, what needs to be done is to build a radio equiv to how PCs are now done. First you would have a generic case, these could be made by anyone, in any design. *The would provide the user with an abundance of choice in the looks of the rig. Next, each section of the radio would simply be a plug in card, to a "mother board." *You would have an rf section, which could cover any and all bands, depending on construction, it would simple plug into one of the slots on the motherboard. *Audio, rf, filter, conversion, etc., etc. could be done this way. You would have a basic set of all sections, and could expand, or upgrade as you would have -- or as becomes available. It would change the face of radio, SW radios would become as numerous as PCs -- well, almost. Most any small manufacturer could enter the market, and provide a case, rf section, audio section, etc. -- and expand from there, if they choose. I simply can't get enough interest ... but the radio could be just am, am fm, am-fm-sw, am-fm-sw-vhf, am-fm-sw-vhf-uhf, am-fm-sw-vhf-uhf-shf, or any possible combination wanted ... this is an idea whose obvious advantage, for consumers, is simply screaming out for production! Later, if one wished, he could just buy a larger standard case, move his receiver components over, buy a larger power supply, and drop in the appropriate transmitting section(s.) We simply wait for the radio to leave the age of the horse and buggy ... Regards, JS But.... 99% of radio buyers have little idea what features they want, and the very slow change in feature sets of each module are in most cases of close to zero interest to end users. Plus radios seldom become obsolete - even 1920s sets are still usable, for the few of us that wish to. Unit radio did of course exist in the early 20s, when radio technology really was changing fast, and it made a significant difference. Come the 30s it was gone though, even though the technology was still changing fast. End users didn't vote for it. A slightly similar approach was also tried in tv in the 70s, with lots of small pcbs that could each be replaced affordably if it ever failed. But ultimately buyers just wanted the cheapest, not to pay for later repairability. I had one of those and when there was a failure discovered that just one board cost half what the entire TV set had, and that was with me doing the diagnosis, meaning I didn't have the cost of a 'TV service man' plowed on top of it. That doesn't strike me as a terribly good deal on 'repairability'. It would, of course, go dead with a hurricane coming so I didn't have much time and used the "hold in breaker, see what smokes" test. A quick check of the schematic to see why and what else might have gone with it and I fixed the thing with a couple of zeners and a resistor. I often wonder if the 'modular PCB' idea was so 'tube test and replace' repairmen could use the same technique on the solid state stuff but a $250 PCB isn't a 3 buck tube. The economics just don't work. Does anyone other than John think there's commercial mileage in modular radio now? I don't because, for one, the 'computer' analogy is flawed. Computer peripherals operate parallel on a common bus and they're not dependent on the others. You can have 'no extras' and still have a computer, or pick and chose whatever 'extra' things you want, like a TV tuner card. It's the common, well defined, bus that makes this work but, even then, it isn't 'free', which is why you see low cost PCs with all the 'typical' things stuffed onto the motherboard and maybe one or two 'expansion slot(s)', if any. A radio, on the other hand, is essentially serial in operation with signal coming in one end and out the other. Remove any part and you no longer have a radio so you 'need them all' to begin with and there's little reason to later change it even if you could (unlikely) figure out how to enforce some common 'interface' at every stage through the whole thing. And then there's the added cost at every single interface break. Bottom line, for the performance/cost ratio you can't beat solid state and a robot assembling the stuff at warp speed. And it can be done so cheaply you're better off to chuck it and buy another one assembled at warp speed. NT |
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#35
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Dec 3, 3:06*am, flipper wrote:
On Fri, 2 Dec 2011 17:48:46 -0800 (PST), NT wrote: On Nov 27, 7:27*pm, John Smith wrote: On 11/10/2011 9:52 PM, wrote: * With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. ... Any other comments? As I once pointed out, long ago, now, in an amateur group, what needs to be done is to build a radio equiv to how PCs are now done. First you would have a generic case, these could be made by anyone, in any design. *The would provide the user with an abundance of choice in the looks of the rig. Next, each section of the radio would simply be a plug in card, to a "mother board." *You would have an rf section, which could cover any and all bands, depending on construction, it would simple plug into one of the slots on the motherboard. *Audio, rf, filter, conversion, etc., etc. could be done this way. You would have a basic set of all sections, and could expand, or upgrade as you would have -- or as becomes available. It would change the face of radio, SW radios would become as numerous as PCs -- well, almost. Most any small manufacturer could enter the market, and provide a case, rf section, audio section, etc. -- and expand from there, if they choose. I simply can't get enough interest ... but the radio could be just am, am fm, am-fm-sw, am-fm-sw-vhf, am-fm-sw-vhf-uhf, am-fm-sw-vhf-uhf-shf, or any possible combination wanted ... this is an idea whose obvious advantage, for consumers, is simply screaming out for production! Later, if one wished, he could just buy a larger standard case, move his receiver components over, buy a larger power supply, and drop in the appropriate transmitting section(s.) We simply wait for the radio to leave the age of the horse and buggy .... Regards, JS But.... 99% of radio buyers have little idea what features they want, and the very slow change in feature sets of each module are in most cases of close to zero interest to end users. Plus radios seldom become obsolete - even 1920s sets are still usable, for the few of us that wish to. Unit radio did of course exist in the early 20s, when radio technology really was changing fast, and it made a significant difference. Come the 30s it was gone though, even though the technology was still changing fast. End users didn't vote for it. A slightly similar approach was also tried in tv in the 70s, with lots of small pcbs that could each be replaced affordably if it ever failed. But ultimately buyers just wanted the cheapest, not to pay for later repairability. I had one of those and when there was a failure discovered that just one board cost half what the entire TV set had, and that was with me doing the diagnosis, meaning I didn't have the cost of a 'TV service man' plowed on top of it. That doesn't strike me as a terribly good deal on 'repairability'. Dead tvs with boards to take out are relatively cheap. The last of those tvs i played with had dire soldering, and I suspected the modularisation was necessary to make such bad soldering produce a useful percentage of ok boards. It would, of course, go dead with a hurricane coming so I didn't have much time and used the "hold in breaker, see what smokes" test. A quick check of the schematic to see why and what else might have gone with it and I fixed the thing with a couple of zeners and a resistor. I often wonder if the 'modular PCB' idea was so 'tube test and replace' repairmen could use the same technique on the solid state stuff but a $250 PCB isn't a 3 buck tube. The economics just don't work. I suspect lack of joined up thinking. Designers think it makes the sets repairable and reduce the pile of dead boards, so implement it. Then later the parts dept realise they can chanrge a pretty penny for these little boards, so do. It kills the original idea of course. Does anyone other than John think there's commercial mileage in modular radio now? I don't because, for one, the 'computer' analogy is flawed. Computer peripherals operate parallel on a common bus and they're not dependent on the others. You can have 'no extras' and still have a computer, or pick and chose whatever 'extra' things you want, like a TV tuner card. It's the common, well defined, bus that makes this work but, even then, it isn't 'free', which is why you see low cost PCs with all the 'typical' things stuffed onto the motherboard and maybe one or two 'expansion slot(s)', if any. A radio, on the other hand, is essentially serial in operation with signal coming in one end and out the other. Remove any part and you no longer have a radio so you 'need them all' to begin with and there's little reason to later change it even if you could (unlikely) figure out how to enforce some common 'interface' at every stage through the whole thing. And then there's the added cost at every single interface break. Bottom line, for the performance/cost ratio you can't beat solid state and a robot assembling the stuff at warp speed. And it can be done so cheaply you're better off to chuck it and buy another one assembled at warp speed. NT The interface question is fairly easy, pick your interface standards and award use of your system logo to any product that complies with these standards. You can probably get away with only one standard, and make match current practice of around 0.1-0.2v 10k at af. Computers cost around 10x as much as a radio. So the extra cost of modularising is low in percentage terms for pcs, but high for radios. And the savings of modularisation for pcs are medium to high, but for radios are mostly low. NT |
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#36
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Tue, 13 Dec 2011 18:08:49 -0800 (PST), NT
wrote: On Dec 3, 3:06*am, flipper wrote: On Fri, 2 Dec 2011 17:48:46 -0800 (PST), NT wrote: On Nov 27, 7:27*pm, John Smith wrote: On 11/10/2011 9:52 PM, wrote: * With the survivalist market as well as the DIYers who would build a kit I have given thought to the idea of building a new tube shortwave receiver as a usable, practical set. ... Any other comments? As I once pointed out, long ago, now, in an amateur group, what needs to be done is to build a radio equiv to how PCs are now done. First you would have a generic case, these could be made by anyone, in any design. *The would provide the user with an abundance of choice in the looks of the rig. Next, each section of the radio would simply be a plug in card, to a "mother board." *You would have an rf section, which could cover any and all bands, depending on construction, it would simple plug into one of the slots on the motherboard. *Audio, rf, filter, conversion, etc., etc. could be done this way. You would have a basic set of all sections, and could expand, or upgrade as you would have -- or as becomes available. It would change the face of radio, SW radios would become as numerous as PCs -- well, almost. Most any small manufacturer could enter the market, and provide a case, rf section, audio section, etc. -- and expand from there, if they choose. I simply can't get enough interest ... but the radio could be just am, am fm, am-fm-sw, am-fm-sw-vhf, am-fm-sw-vhf-uhf, am-fm-sw-vhf-uhf-shf, or any possible combination wanted ... this is an idea whose obvious advantage, for consumers, is simply screaming out for production! Later, if one wished, he could just buy a larger standard case, move his receiver components over, buy a larger power supply, and drop in the appropriate transmitting section(s.) We simply wait for the radio to leave the age of the horse and buggy ... Regards, JS But.... 99% of radio buyers have little idea what features they want, and the very slow change in feature sets of each module are in most cases of close to zero interest to end users. Plus radios seldom become obsolete - even 1920s sets are still usable, for the few of us that wish to. Unit radio did of course exist in the early 20s, when radio technology really was changing fast, and it made a significant difference. Come the 30s it was gone though, even though the technology was still changing fast. End users didn't vote for it. A slightly similar approach was also tried in tv in the 70s, with lots of small pcbs that could each be replaced affordably if it ever failed. But ultimately buyers just wanted the cheapest, not to pay for later repairability. I had one of those and when there was a failure discovered that just one board cost half what the entire TV set had, and that was with me doing the diagnosis, meaning I didn't have the cost of a 'TV service man' plowed on top of it. That doesn't strike me as a terribly good deal on 'repairability'. Dead tvs with boards to take out are relatively cheap. Not back then and even if there was one there wasn't an Internet, Craigslist, and Ebay to find it. And even if you get past all that a hurricane was on the way and even in this day and age things don't instantaneously appear on your doorstep. The last of those tvs i played with had dire soldering, and I suspected the modularisation was necessary to make such bad soldering produce a useful percentage of ok boards. I was being a bit flippant but I think you've hit the target. It's a lot more likely the reason for modularity was for in house test and manufacture than a noble notion of home repairability. Someone might have thrown it in as an additional 'feature' but I doubt it was the primary factor. It would, of course, go dead with a hurricane coming so I didn't have much time and used the "hold in breaker, see what smokes" test. A quick check of the schematic to see why and what else might have gone with it and I fixed the thing with a couple of zeners and a resistor. I often wonder if the 'modular PCB' idea was so 'tube test and replace' repairmen could use the same technique on the solid state stuff but a $250 PCB isn't a 3 buck tube. The economics just don't work. I suspect lack of joined up thinking. Designers think it makes the sets repairable and reduce the pile of dead boards, so implement it. Then later the parts dept realise they can chanrge a pretty penny for these little boards, so do. It kills the original idea of course. No company I've been in has been that 'disjointed' and departments don't get to charge whatever they think a good idea. It's usually a well planned, from all angles, cost/profit margin analysis including expected warranty and after sales service revenues. That doesn't mean they necessarily get it 'right' but if that were 'the plan' they sure wouldn't let some yahoo in the parts department arbitrarily screw it up. Does anyone other than John think there's commercial mileage in modular radio now? I don't because, for one, the 'computer' analogy is flawed. Computer peripherals operate parallel on a common bus and they're not dependent on the others. You can have 'no extras' and still have a computer, or pick and chose whatever 'extra' things you want, like a TV tuner card. It's the common, well defined, bus that makes this work but, even then, it isn't 'free', which is why you see low cost PCs with all the 'typical' things stuffed onto the motherboard and maybe one or two 'expansion slot(s)', if any. A radio, on the other hand, is essentially serial in operation with signal coming in one end and out the other. Remove any part and you no longer have a radio so you 'need them all' to begin with and there's little reason to later change it even if you could (unlikely) figure out how to enforce some common 'interface' at every stage through the whole thing. And then there's the added cost at every single interface break. Bottom line, for the performance/cost ratio you can't beat solid state and a robot assembling the stuff at warp speed. And it can be done so cheaply you're better off to chuck it and buy another one assembled at warp speed. NT The interface question is fairly easy, pick your interface standards and award use of your system logo to any product that complies with these standards. You can probably get away with only one standard, and make match current practice of around 0.1-0.2v 10k at af. Computers cost around 10x as much as a radio. So the extra cost of modularising is low in percentage terms for pcs, but high for radios. And the savings of modularisation for pcs are medium to high, but for radios are mostly low. Yeah, I just don't see it but, hey, if someone has the guts and capital then that's what free enterprise is all about. NT |
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#37
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On 12/2/2011 7:06 PM, flipper wrote:
... Bottom line, for the performance/cost ratio you can't beat solid state and a robot assembling the stuff at warp speed. And it can be done so cheaply you're better off to chuck it and buy another one assembled at warp speed. NT Yeah, like computers. Every year I build another, from components ... however, I usually choose to keep my video card if no major improvements in them are available ... keep my 1200W power supply--since it still provide much more power than I am using, keep my network card ... But, a new motherboard is something frequently upgraded--along with processor ... maybe memory ... maybe hard disk ... etc. Modularized radio and you could have dozens of audio boards, low to high end audio, right up to HD ... new dials, new readouts, new 3.0 USB interface to a computer, etc. No, modular radio simply would be best for consumer and bad for manufacturers ... who like very proprietary systems ... they would scream at having to attempt with a generic radio platform which could be just am or any combination right up to microwave bands ... But, you did manage to mention the real truth of why it is not demanded by consumers ... consumers are simply too stoopid to realize the benefits and ask for them ... end of story. Regards, JS |
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#38
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Dec 14, 8:21*pm, John Smith wrote:
On 12/2/2011 7:06 PM, flipper wrote: ... Bottom line, for the performance/cost ratio you can't beat solid state and a robot assembling the stuff at warp speed. And it can be done so cheaply you're better off to chuck it and buy another one assembled at warp speed. NT Yeah, like computers. *Every year I build another, from components ... however, I usually choose to keep my video card if no major improvements in them are available ... keep my 1200W power supply--since it still provide much more power than I am using, keep my network card ... But, *a new motherboard is something frequently upgraded--along with processor ... maybe memory ... maybe hard disk ... etc. Modularized radio and you could have dozens of audio boards, low to high end audio, right up to HD ... new dials, new readouts, new 3.0 USB interface to a computer, etc. No, modular radio simply would be best for consumer and bad for manufacturers ... who like very proprietary systems ... they would scream at having to attempt with a generic radio platform which could be just am or any combination right up to microwave bands ... But, you did manage to mention the real truth of why it is not demanded by consumers ... consumers are simply too stoopid to realize the benefits and ask for them ... end of story. Regards, JS Its usually the manufacturer that introduces a new line, consumers can only buy from what's available. NT |
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#39
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Wed, 14 Dec 2011 12:21:58 -0800, John Smith
wrote: On 12/2/2011 7:06 PM, flipper wrote: ... Bottom line, for the performance/cost ratio you can't beat solid state and a robot assembling the stuff at warp speed. And it can be done so cheaply you're better off to chuck it and buy another one assembled at warp speed. NT Yeah, like computers. Actually, no, and that was the point. They're not 'like computers'. Every year I build another, from components ... however, I usually choose to keep my video card if no major improvements in them are available ... keep my 1200W power supply--since it still provide much more power than I am using, keep my network card ... But, a new motherboard is something frequently upgraded--along with processor ... maybe memory ... maybe hard disk ... etc. So do I. But I wouldn't if, like the 'modular TV' brought up elsewhere (or a radio), each of the 'modular parts' cost darn near as much as the whole thing. Or, put the other way, I wouldn't if I could buy a 'whole' new one for only a little more than the cost of a hard drive. Modularized radio and you could have dozens of audio boards, low to high end audio, right up to HD ... new dials, new readouts, new 3.0 USB interface to a computer, etc. If you're going to replace all that you might as well save the interface crap and stuff the rest of the parts for a whole radio. Not to mention there's no reason to 'right up to' HD when the detector isn't and the band isn't either. So you have to change all that, which is a whole blooming radio. No, modular radio simply would be best for consumer and bad for manufacturers ... who like very proprietary systems ... "Like a computer," eh? they would scream at having to attempt with a generic radio platform which could be just am or any combination right up to microwave bands ... Ah yes, the good ole 'industry conspiracy' crap. But, you did manage to mention the real truth of why it is not demanded by consumers ... consumers are simply too stoopid to realize the benefits and ask for them ... end of story. I can see you're not going to be in the sales department. Regards, JS |
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#40
Posted to rec.audio.tubes,rec.radio.shortwave
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Building a new shortwave tube radio
On Fri, 2 Dec 2011, NT wrote:
Does anyone other than John think there's commercial mileage in modular radio now? Not as portrayed, and certainly not as a general radio. There have been articles about building in modular form and even some kits that were modular, and of course it's a great form for experimenting, why remake the whole radio if you want to try a new IF strip or add a new detector? Or buy the modules you want to build up something, rather than be stuck with what the complete radio the company sells. But there can't be a general bus, one module takes its input from the antenna or a previous module, and its output goes to the next module, those have to be well isolated. The power supply is standard to each module, the whole point of three terminal regulators was to make regulation specific to boards rather than one big power supply feeding everything. But control lines will be different depending on the function of the module, some requiring lots of lines, others requiring few or none at all. And there's no way it would be for everyone. The average radio user doesn't care, they just want AM/FM radio, nowadays not even AM and a radio is a radio, once you have one for average use there's no need for improvement. A modular radio might be interesting to the hobbyist, which of course is where the concept has travelled. It's there in all the VHF converters described in the hobby magazines, getting extra coverage with a shortwave radio at the cost of a "module", ie converter, rather than having to build a whole new radio. It's the hobbyist that wants to try things, it's the hobbyist that is interested in the radio in itself. They are the ones who might want to do better on longwave, or listen to the police band (even then, or a lot of that type of hobbyist, existing scanners are more than enough). For a small company aimed at the hobbyist, modules make sense. They dont' ahve to offer multiple receivers, just enough modules for someone to put together what they want. I long ago argued with a friend that if he was going to go into a small electronic business, just selling boards made sense, since then he's not involved in dealing with cabinetry. The hobbyist can buy the modules and then take care of putting it in a case. It's a fairly limited market, yet at one point was one that might do okay. You can have a successful business without making loads of profit, and indeed doing away with things like UL approval by using an existing AC adapter or having the buyer come up with one keeps overhead down, as does the lack of cabinetry. Find a market that really exists, and cater to it, you may not be rich but the business may keep going. I have no idea if the market is there anymore. I've been going through old magazines lately, and it reminds me how much time and even money I spent on magazines, the hobby electronic ones and the ham magazines, and I feel detached to it as the magazines disappeared, virtually no hobby electronic magazines in North America, and the ham magazines dwindling but more important less available on newsstands than in the old days. The magazines were pretty important, and I'm not sure they really have been replaced with other things. If nothing else, they were way to keep track of the companies that sold kits and parts. A different way to look at it is to think about commercial shortwave receivers. They have become really cheap, and fairly good. I paid somewhere around $80 for a Hallicrafters S-120A (the transistorized one) in the summer of 1971, the most I could afford, the cheapest receiver I could find locally. It was junk, the only good thing about it was I had no experience so I didn't know how bad it was for a bit. You can get a Grundig Yacht Boy 400 (or whatever the same model in a different cabinet is) for a hundred dollars, some of the other Etons for the same complete with synchronous detector. For that matter, I am finding sw receivers at rummage and garage sales now for pretty low amounts. That Grundig Satellite 700 for 2.00 at the Rotary Club sale, that Sony ICF-SW1 at a garage sale in September for 10.00 (and then about half an hour later an Eton Mini 300 for 2.00 at another garage sale, though that is junk). They are infinitely better than the old low end analog receivers. People talk about buying all kinds of models, but nobody seems to think that if a hundred dollars is seen as "disposable" then why not buy a radio to modify extensively? Buy one and put it into a bigger cabinet. Make it a desktop physically, complete with a good tuning knob on the front panel. Even receivers with up/down buttons can be tuned with a tuning knob. All those people who judge a radio by "sound", they can put a nice big speaker in the cabinet, though better to use an external speaker. Add better lighting to the LCD display. Add that Q-multiplier. Add some filters if you can get some at the proper IF frequency. The radio becomes the foundation to customize. Add an FM IF strip and then feed the radio with converters to hear those higher bands. Put some more front end selectivity in the box, yes suddenly you'd have to tune it in addition to the tuning knob, but that's the way it used to be on the good receivers anyway. It doesn't have fine enough tuning? Then add a variable capacitor across the second conversion oscillator (either directory or via a varicap), and you can get a fine tuning knob that isn't linked to the BFO. For that matter, one could splurge and add crystal controlled BFO, getting the frequencies to be in the right place in relation to the IF filter. What's wrong with current receivers that can be improved with a little bit of work? Some things can't be fixed, but a lot of these new receivers offer a pretty good foundation compared to what there was in the old days. YOu start with a reasonably good receiver, you see the low cost so you aren't afraid to hurt it, and you make it the receiver you want, just like someone would want those modules for. Michael |
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