[Milsurplus] GB> RCA TRANSMITTER ID REQUESTED

[Mike Morrow]

Hue Miller wrote:

>Forwarded for any info you readers might have:
>From: "Greg Mijal"
>
>Found an aircraft transmitter at the William Arizona hamfest yesterday.
>If anyone can help me with identifying it, I sure would appreciate it.  Would
>like to power it up and see what happens.  Got a couple of crystals with it
>and an old aircraft PTT mic too. It's marked: RCA AVT-111 Inside it's got
>4 6V6's. 

That's a 1940s-era light aircraft transmitter, normally crystalled for 3105 kc or the later replacement frequency of 3023.5 kc, used for ground to tower communication.  The AVT-111 could also double the crystal frequency for operation on 6210 kcs.

It would likely have been paired with something like an AVR-100 Beacon Band (200 - 400 kcs)/Broadcast Band (550 - 1500 kcs) receiver to home on directional A-N beacons and to receive the standard tower frequency of 278 kcs.

>Where's the modulator?

Two of the 6V6 tubes are push-pull PA plate modulators.  One 6V6 is the oscillator, the other is the PA.

The microphone is a carbon mic.

>What's the pinout for the double row Cinch Jones on the back?

Pin      Function
1        Mic tip (PTT)
2        A+  +12 vdc (if wired for 12 vdc)
3        Mic ring (audio)
4        Remote heater ON switch (ground to turn on heaters).
5        Modulator Sidetone out
6        Modulator Sidetone out
7        Same as pin 2
8        Mic tip (PTT) (to external relay)
9        B+  (about +250 vdc, I think) 
10      Ground (common)

The set used an external vibrator supply.

73,
Mike / KK5F