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Don Snodgrass
 
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Default Audio processing techniques for Amateur Radio

Hello to the group...

I've been a licensed Amateur Radio operator since 1972. Recently, I and
other Amateurs have been experimenting with the use of external audio
processing equipment to enhance our transmitted audio quality. You can
learn more about this by visiting my Amateur Radio site at
http://webpages.charter.net/donsno/wb4kr.htm . This site is fairly complete
including a description of equipment, hookup scheme, settings, etc. I even
have a link to a sound bite.

Relatively narrow radio transmission bandwidth severely challenges my
ability to replicate the kind of results most of you are accustomed to.
That's because Amateur Radio transmitters are typically restricted to a
narrow bandwidth of 100 Hz to 3000 Hz when transmitting single sideband
(SSB) information.

What I try to do is to make the most effective use of studio mics, preamps,
EQs and other processing equipment. However, not being a professional
audio engineer, I often feel frustrated with my efforts to find the right
equipment settings. I end up resorting to a trial and error approach
testing the results of settings with other Amateur Radio operators over the
air. I've also have tried to use audio analysis software such as
SpectraPLUS with equally frustrating outcomes.

Any comments/advice/recommendations would be appreciated. Please visit
the above link and let me know what you think of my equipment settings.
Perhaps you have some other settings that you feel might yield better
results. Input from those using the Behringer DEQ2496 for processing male
vocals would be especially welcome.

Best wishes,

Don
Amateur Radio Station K4QKY

--


Don Snodgrass
1624 Tabard Drive
Murray, KY 42071
270-767-9944

http://webpages.charter.net/donsno





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Scott Dorsey
 
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Default

Don Snodgrass wrote:

Relatively narrow radio transmission bandwidth severely challenges my
ability to replicate the kind of results most of you are accustomed to.
That's because Amateur Radio transmitters are typically restricted to a
narrow bandwidth of 100 Hz to 3000 Hz when transmitting single sideband
(SSB) information.


So skip the SSB stuff and all the associated group delay that comes along
with all those phasing networks, and join the crowd on 40M AM. No kids,
no lids, no space cadets. Plate modulation preferred although you won't
get derided too strongly for screen grid modulation.

What I try to do is to make the most effective use of studio mics, preamps,
EQs and other processing equipment. However, not being a professional
audio engineer, I often feel frustrated with my efforts to find the right
equipment settings. I end up resorting to a trial and error approach
testing the results of settings with other Amateur Radio operators over the
air. I've also have tried to use audio analysis software such as
SpectraPLUS with equally frustrating outcomes.


Record yourself, and listen to it. Since the whole SSB airchain is going
to have outrageous group delay, what sounds clean going into the
transmitter may not be at all optimal for what comes out. You might consider
recording your voice to tape, running into a dummy load, and adjusting the
processing as you listen to your voice on tape through a receiver. That way
you get a chance to hear what is going on through the whole chain.

Any comments/advice/recommendations would be appreciated. Please visit
the above link and let me know what you think of my equipment settings.
Perhaps you have some other settings that you feel might yield better
results. Input from those using the Behringer DEQ2496 for processing male
vocals would be especially welcome.


How can anyone tell anything by looking at your settings? All anyone can
really tell is how your audio sounds by listening.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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On 2004-05-07
(ScottDorsey) said:
wrote:
i do a lot of work on hf, using a HEil mic with the stock ICom gear
and from recordings I've heard of my audio its acceptable. I work
with folks using gear for the hf maritime services etc. and you'll
notice their audio is not near as full range because of even more
severe bandwidth limitations.

In the case of SSB, some of the things that will help your signal
get out farther are directly contrary to better sound quality.
Restricting signal bandwidth means more power per unit bandwidth
getting out. Heavy limiting, possibly using something like the
Turner communication mike, brings more definition to consonants.
The voice sounds buzzy and unnatural but it's more understandable
on the radio. If your goal isn't maximum intelligibility like the
DXers, though, there's a lot of playing room. Talk to Addison Inge,
AA4AV, who is one of the crazy wideband SSB audio guys and who has
been trying out a bunch of my Oktava 219 mike mods this week.

I bought the Heil, about the size of an sm-58, a little larger barrel
however, because I destroy headset mics and I like the foot switch
because I do a lot of net control work as well as traffic handling.
THerefore I need my hands free to use the computer and read braille.
IF I want to kick back in the chair I put the mic on an Atlas boom
stand, otherwise it rests on a table stand directly behinc my computer
keyboard.

I thought about playing with a SEnn 421 and different processing a few
months ago but decided I wasn't going to gain that much for the type
of work I do on the radio.

watch your bandwidth with a scope and strive for maximum
intelligibility. That's the whole point of communications audio.
It isn't about high fidelity, it's about inteligibility in poor
conditions.

There is a weird sort of subculture, which can be found often on
40M AM, who seem obsessed with audio quality often at the expense
of intelligibility on the ham bands. I don't get it, personally.


I listen to those guys occasionally as well and I don't understand.
THere again its a horses for courses issue. SSB was not designed to
be a high fidelity mode, it was made to save bandwidth and increase
efficiency. NOw if you were one of the guys playing on am then I
could understand that.

I'm not quite as piercing as some of the dx hounds but have reached a
reasonable compromise from what I've heard of my audio. IT seems to
me that you don't try to move your residence using a compact car and
you don't drive the big moving van as a commuter vehicle. Same goes
with audio. cOmmunications audio especially on hf is a whole
different bucket of worms than studio quality audio for production
work.

MOst folks whom I hear that could improve their audio should first
look into improving their station grounding and other areas first.
YOu'd be amazed at the number of stations I hear handling traffic and
doing public service work that have rf feedback problems and other
nastiness.

I still maintain that some wide area link systems have some pretty
crappy audio by the time the guy with the ht or mobile gets his signal
fed through a two meter repeater, a uhf link then another two meter
repeater and its associated uhf links etc. A guy I know back in Iowa
was working with the sOutheast Iowa link system and some equalization
trying to improve things just a bit but ...






Richard Webb
Electric Spider Productions
REplace anything before the @ symbol with elspider for real email

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