[Milsurplus] ATD Transmitter

[Meir-WF2U]

Moe,

Mike, Robert and Dennis said it all...

Mike, there is something here we were just corresponding about.

I just want to add that I'm working on an ATD/ARB combo so I can put it on
the air.
My ATD looked like original but I found a few modifications in it which I'm
taking out to restore it to original. I found a NOS dynamotor for it, I
bought the manual and connectors from Robert, and I fired up the ATD last
Sunday.
No sparks/smoke, the dyno is relatively quiet. The oscillator (I had one of
the TU's on 3700 KHz) is stable, but the grid drive to the final was very
low and the tuning didn't work right. The plate current was also low and I
got only 6 W out.
Tonight I had a few minutes and got the covers off. I found a capacitor
tacked on the grid pin of the 814 final, and that was connected to a piece
of miniature coax, which went to a 1/4" shorting audio jack. (Attempt to
drive the final from an external source?)
I just yanked out that thing, but didn't fire it up again yet.
There was also an extra bypass capacitor tacked on to the bottom of the
plate choke. Mike's photo doesn't show that cap, the original is under the
chassis, next to the modulation transmitter. At worse the extra cap may
cause some unwanted resonance in the plate circuit, but the least is that
it'll cut off some high frequencies from the audio when it's on AM.

Interesting how another ATD popped up - I wanted to post a query whether
anyone else on the list is playing with and ATD...

It's a "cute" rig and would be really fun to make it work!

Good luck, Moe!

73, Meir WF2U
Landrum, SC 

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Moe Fretz
Sent: Tuesday, September 30, 2008 7:03 PM
To: Milsurplus at mailman.qth.net
Subject: [Milsurplus] ADT Transmitter

Have found an Bendix ATD transmitter located in a old barn. Covered
and not disturbed by rodents yet. I am looking for some info on these
transmitters as I have never see one before. Any help would be
helpful.   Thanks to all

http://pic20.picturetrail.com/VOL1601/8089626/15164243/336748652.jpg

-- 
Moe Fretz
Collection and Preservation
Of Canadian Tube Radios,
Communication Equipment,
Vintage Ham gear and Military Radios.

Don't crush them ---- Restore them.


Ontario Canada
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