On Wed, 13 Jun 2012 15:48:48 -0500, John Byrns
wrote:
In article ,
flipper wrote:
Okay, so I like to make up cutesy names 
I wanted to do 'something' with a 6ME8 so I tried using it for an AM
transmitter and the first prototype works rather well. Bandwidth is
'too much', less than 1 dB down at 18 KHz, but we'll worry about that
later.
This is a 'dollar days' special, 2 whole bucks worth of tubes, and L2
is a UHF converter coil scramble rewound, so that was 'free'. Power
supply is from the same converter and if the remaining issues get
worked out it'll probably end up in that cabinet as well (but where to
put the air variable?).
The schematic is rough, but should be rather self explanatory, and the
ganged tuning hasn't been fleshed out yet. I'm still using separate
caps while jiggling things around.
Orphaned web page, not yet ready for prime time, has a recording of it
playing through a table radio.
http://flipperhome.dyndns.org/Beamus.htm
Hi Flipper,
Dropping the ganged capacitor was probably a good idea, if it was a
superheterodyne capacitor there was probably no way you could have made it track
correctly. Did you ever think of using a crystal in the oscillator circuit,
that way there would be only one tuning adjustment?
I wanted the frequency, at least some degree, tunable.
What is the potentiometer
in the oscillator screen circuit all about,
That adjusts osc RF amplitude to the deflector plates.
what is the criterion for adjusting
it?
I'm still pondering that a bit but current procedure is to run it up
to near max mod and adjust for maximum peak to peak.
You state that 80 Vpp on the plate equates to about 35 mW, how did you calculate
that?
That's guesstimated EI across the plate load.