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THE AM BULLETIN BOARD => Technical Forum => Topic started by: N0WEK on November 25, 2008, 11:05:26 PM



Title: I couldn't pass this up...but what is it?
Post by: N0WEK on November 25, 2008, 11:05:26 PM
I bought this thing on Ebay. It looks like some partially built older project with a pile of meters and a four 832s.

Does anyone recognize this project from some old Handbook or have any idea what it was supposed to be?

If nothing else it's a good start on something or a lot of great parts.

Good pictures here...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=160299579654

Greg


Title: Re: I couldn't pass this up...but what is it?
Post by: Opcom on November 26, 2008, 01:19:55 AM
what in the world.. I don't see any tanks but they could be above the tubes out of sight. Nicely made and a value for the price! I wonder if it is some kind of pulse generator power stage? too wierd.


Title: Re: I couldn't pass this up...but what is it?
Post by: ab3al on November 26, 2008, 07:03:21 AM
flux capacitor ??


Title: Re: I couldn't pass this up...but what is it?
Post by: K3ZS on November 26, 2008, 09:42:50 AM
Looks like a balanced something from the front panel layout.


Title: Re: I couldn't pass this up...but what is it?
Post by: W9GT on November 26, 2008, 12:06:27 PM
Looks like a vintage VHF rig.  What is the xtal freq?  You might be able to figure out what the operating freq was by multiplying the fundemental freq by different multiples and see what you come up with.  832s are dual tetrodes, I believe.  Kinda like lower power versions of 829Bs.  Nice parts rig anyway.

73,  Jack, W9GT


Title: Re: I couldn't pass this up...but what is it?
Post by: N0WEK on November 26, 2008, 12:37:04 PM
From what I can see in the pictures, it looks like the xtal is 28202 khz which might make it a 10 meter rig or if doubled twice would put it in the old WWII 2 1/2 meter band, which is now right in the middle of the vhf aircraft allocation.

When I get it I'll take better pictures and work up a schematic and see what's there.

The two lower knobs seem to have extensions that line up with a couple of holes in the lower chassis. Interesting to see what might mount there.

I do have some 829s in stock too!
 


Title: Re: I couldn't pass this up...but what is it?
Post by: Ed - N3LHB on November 27, 2008, 12:16:42 AM
Might very well be a part of this.... Check out the Rockwell video

http://www.wv7u.com/audiovideo/retro.wmv


Title: Re: I couldn't pass this up...but what is it?
Post by: KB5MD on November 27, 2008, 09:49:51 AM
Since you out bid me and got the thing, I'm not going to tell you what it is!  But, it is definitely one of those.   ;) Have fun with it. 


Title: Re: I couldn't pass this up...but what is it?
Post by: W1ATR on November 27, 2008, 08:40:22 PM
You don't want to know what that is. Just a useless pile of junk. Wanna sell it. ;D


Title: Re: I couldn't pass this up...but what is it?
Post by: N0WEK on December 06, 2008, 12:20:17 PM
The transmitter showed up in good shape.

I haven't drawn out the schematic but it looks like it's really two identical transmitters side by side. The oscillator plugs into an octal socket and has a 24.212 xtal in it which triples up to 72.636 and then doubles up to 145.272. As far as I can tell with a quick look it's oscillator and two push pull 832s and then link coupled to the antenna connector. The covers and link/ant connector is missing from one side and the oscillator is missing from the other. Power supply and modulator would be fed in from the sockets on the back.

I guess it'd be one way to be frequency agile.

It's very professional work.

I may try to put it on the air.

Still no ideas about who built it or from what plans, if any?


Title: Re: I couldn't pass this up...but what is it?
Post by: KA2PYQ on December 06, 2008, 01:49:09 PM
If it`s two transmitters side by side maybe you could up
the ante. Shunt the meters, put 4 3X2500A3 triodes in 4
inside corners with blowers and vacuum variables, build
an exciter beneath and 4 modulators and so on. "AM JAM
BOREE. Swimsuit optional but your transmitter must be
on AM.". -Floyd Dunlap, late WA5TWF.


Title: Re: I couldn't pass this up...but what is it?
Post by: WU2D on December 10, 2008, 06:07:42 PM
Nice shielded and balanced construction - No 1950's TVI here OM!

Those 832s make good triplers and they were certainly made by the boat load for the SCR-522's VHF ARC-5's etc..

They are still regarded as pretty much tube fodder at hamfests but if you drag some home, be careful where you sit.

You might be able to get 15 Watts out of an 832 on 2M. I converted an SCR-522 transmitter and swapped out the 832 for an 829B by shimming the socket and got 25 Watts out on 2M AM.

Mike WU2D
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands