need help identifying device

[Lloyd KK7IZ]

I may be wrong, but it looks to me like an old induction heater RF 
generator. Bet it works at about 13.5 mcs or 27 mcs. (mhz hadn't been 
invented yet when this stuff was built)
Thanx
Lloyd  KK7IZ
kk7iz at cox.net


----- Original Message ----- 
From: "WSHU Engineering2" <paull at WSHU.ORG>
To: <BOATANCHORS at LISTS.TEMPE.GOV>
Sent: Monday, September 29, 2008 8:51 AM
Subject: need help identifying device


> My assistant  Tony just picked this Frankenstein device up at a live 
> auction. Pictures are on the link below.
> It has two mercury vapor rectifiers (one broken) and two large triodes The 
> triodes are type 3581, they look like 810s minus the side mounted grid 
> pin, the grid connection is on the bottom pins. It contains a plate 
> transformer but no filter cap, so the RF product would be modulated by the 
> 120 hertz ripple.
>
> It looks like a variable  push pull oscillator.The plate circuit is tuned 
> by a cap with a knob on the front panel. I have not grid dipped it, but it 
> looks like it is probably in the 20-30 mhz range.
>
> Here is where it gets weird. The tuning cap is labeled Aux volume control, 
> and a grid series resistor is labeled Main Volume Control. I took one of 
> the 3581s out for the picture. What looks like metering jacks seem to be 
> the input/ output connectors but the  grid coils on each side of the plate 
> tank sure look like oscillator ticklers to me. Could be neutralization I 
> suppose if it is some sort of amplifier. Coupling of the plate circuit to 
> the output jacks is via fixed air capacitors.
>
> It has fillament and Plate switches on the front panel and a 500 mA scale 
> meter for plate current.
>
> 120 volt input. Single transformer supplies fillament and B+ voltages
>
> Pics at:
> http://wshu.org/oldradio/device.php
>
> Tony will probably put it up on e-bay if we can figure out what it is, but 
> you can contact him at tpage at wshu.org  should you want to offer something 
> for it and save him the trouble of listing it.
>
> Paul A. Litwinovich
> Director of Engineering
> WSHU AM & FM, WSUF-FM
> FCC License  PG-GB 039245
> N1MUC
> "RF IS GOOD FOR YOU"
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