[R-390] Ballast Tube Thread/Deadest horse that's ever been beat

[Bob Camp]

Hi

You have a perfectly good audio amplifier module in the radio complete 
with transformer coupled outputs. You also have direct access to the 
input of the amplifier at the diode load test point. AM modulation of 
the of the R-390A/URT should be a piece of cake.

Now the for the fully automatic vacuum tube based antenna tuner and the 
muti band triple stack VFO's.

Then we could strap a couple of diodes on the input so it would 
overload like crazy.

We'll have a modern transceiver in no time at all.

	Take Care!

		Bob Camp
		KB8TQ


On Jul 4, 2004, at 1:34 PM, Jerry Kincade wrote:

> Has anybody ever investigated the possibility of switching the 3TF7 
> out with
> a triode-pentode that could do double duty as a ballast and a 
> transmitter?
> Seems like an R-390A/URT Transceiver could be a possiblilty. Heck, you
> already have a T/R relay built in, all the power supplies you need, and
> crystal oscillators. Probably too much to ask for plate modulation, 
> but for
> CW it might be a great rig, if a bit on the overdesigned side on the
> receiver part.
> Jerry W5KP
>
> ----- Original Message -----
> From: <Llgpt at aol.com>
> To: <rbethman at comcast.net>; <r-390 at mailman.qth.net>
> Sent: Sunday, July 04, 2004 12:22 PM
> Subject: Re: [R-390] Ballast Tube Thread/Deadest horse that's ever 
> been beat
>
>
>> Hmmmmmmmmm,
>>
>> Everything was sailing merrily along until now. We need to get the 
>> Mars
>> lander Project people in on this to tell us just how far out of spec 
>> that
> 50 ohm
>> resistor can climb before you can no longer hear a signal. 51 ohms, 
>> in a
> few
>> decades it might be 53-54 ohms. Egads!! I should have listened when I 
>> was
> called
>> a witch for using sand state devices to replace a 
>> tube............live and
>> learn I guess.
>>
>> Les Locklear
>> Monitoring from The Gulf of Mexico
>> Hammarlund HQ-120X
>> Harris RF-505A (R-5075/GRR)
>> R-390/URR
>> Ten Tec RX-350D
>> Alpha Delta Sloper
>> Various Longwires
>> Monitoring since '57
>>
>>
>>
>>
>> In a message dated 7/4/2004 10:19:23 AM Central Daylight Time,
>> rbethman at comcast.net writes:
>> Barry & Les,
>>
>>      I'll play whatever role you wish pursuant in keeping this alive!
>>
>>      I don't get "sucked" into anything!  I JUMP in with my eyes open
> wide.
>>
>>      To make sure it is "on-topic", My 50 ohm has after about 8 or so
>> years of use in lieu of the INFAMOUS 3TF7, has drifted to 51 ohms in
> value.
>>
>>      Happy Fourth!  My spirit is with the new ones doing what us OLD 
>> ones
>> used to!
>>
>> Bob - N0DGN - USA/USN retired
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>
>
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