need help identifying device

[Wilson Lamb]

In the old days, you could hear these on 20m.  At least my dad said so.  Why 
not clean it up and make an amp?
With minor coil changes it could run several hundred Watts on CW.
WL
----- Original Message ----- 
From: "Chuck McGregor" <cbmcg at COMCAST.NET>
To: <BOATANCHORS at LISTS.TEMPE.GOV>
Sent: Monday, September 29, 2008 2:14 PM
Subject: Re: need help identifying device


> Sorry to add to your bad news, but that white panel behind the power tubes 
> of your diathermy machine sure looks like ASBESTOS.
>
> --Chuck N7RHU
>
> WSHU Engineering2 wrote:
>> 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"
>> -----------------------------------------------------------
>
> -----------------------------------------------------------
> This list is a public service of the City of Tempe, Arizona
> -----------------------------------------------------------
>
> Subscription control - 
> http://www.tempe.gov/lists/control.aspx?list=BOATANCHORS
> To post - BOATANCHORS at LISTS.TEMPE.GOV
> Archives - http://lists.tempe.gov/archives/BOATANCHORS.html 

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.aspx?list=BOATANCHORS
To post - BOATANCHORS at LISTS.TEMPE.GOV
Archives - http://lists.tempe.gov/archives/BOATANCHORS.html