[Moon-net] Info Needed on Tubes

[peter blair]

Hi Doug, I used a GL6942 for some years in the1960s/70s. It's a power 
tetrode with 1.5KW anode dissapation, Dick Turrin W2IMU and his mates found 
two  for me to get me QRO on 432. I ran it in a square radial type cavity, 
grounded grid, with a strip line cathode circuit and it would dish out 1KW 
with ease. Drive was probably about 200W from memory. I never had the GE 
data sheets but I found out that it is the "same" tube as the Mullard ( 
Phillips) QY3-1000A and I have those data sheets. There it is rated as 
giving 2.5KW output at 800 MHz with 4.5KV on the plate. I only had about 
2.5KV but with more HT  you would get 1.5 KW out at 432 easily. There is one 
problem... the heater/cathode is a DIRECTLY HEATED thoriated tungsten type 
needing 4V at 60A with 150A surge ( heater chokes were fun to make I recall 
using 10 mm copper strip) and so  you need to wind the heater volts up 
slowly and then down slowly at the end . I used a variac to do this by hand. 
If you dont then the heater will ping and I did lose one that way. Maybe 
others with professional experience of directly heated big tubes can offer 
you more up to date advice. If the cavity tunes 432 and you get the supplies 
together you're in business. Let me know if you need more info, I could scan 
in the data sheets if you cant find it on the web.
 73 and HNY Peter G3LTF
----- Original Message ----- 
From: "Doug Millar" <dougnhelen at moonlink.net>
To: <moon-net at list-serv.davidv.net>; <microwave at wa1mba.org>; 
<sbms at ham-radio.com>; <microwave at qth.net>; <microwave at lists.valinet.com>; 
<mailto:>
Sent: Sunday, December 31, 2006 1:04 AM
Subject: [Moon-net] Info Needed on Tubes


>
> Does anyone have info on the following tubes?
> Y 867
> 7169
> GE 6942
>
> The 6942 is in a huge 432 cavity and the tube has horizontal fins.
> The 7169 is new in the bag about 1962 vintage.
> Doug K6JEY
>
>
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