[AMRadio] 1930's Old Buzzard Open Rack Transmitter


Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Tue Feb 21 22:44:15 EST 2006


The T55 has 55 watts of plate dis, and gives 170 watts out?
The 812A has 65 watts of plate dis and gives 130 to 150 watts out?

I get about 275 watts out at 1500 volts, no color on the plates, 
maybe I should try the T55's, they will give me 340 watts out?

I never even plugged the T55's in or tested them.
Filaments are no problem, I have a panel mount variac 
to adjust the voltage between 0 and 12 volts.

I did try a set of 572b tubes, but they seem to work hard and not
give a lot more power output.

Brett
N2DTS 

> -----Original Message-----
> From: amradio-bounces at mailman.qth.net 
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of crawfish
> Sent: Tuesday, February 21, 2006 10:07 PM
> To: Discussion of AM Radio
> Subject: Re: [AMRadio] 1930's Old Buzzard Open Rack 
> Transmitter FinallySeestheAirwaves! (Long)
> 
> My 1937 Jone Radio handbook says that a T-55 has 55 watt 
> plate dissipation,
> typical 1500 vdc plate voltage with -180 vdc grid bias, max. 
> Ip is 150 mA,
> max. Ig is 30 mA.10 watts RF  in, 170 watts RF out for 225 
> in.7.5 VAC @3.25
> on filament. The 811A is 65 watts plate dissipation, the 
> difference in the
> 811A and the 812 is that the 811A is zero bias and the 812A 
> needs -110 vdc
> bias. Power out of the 811/812 is 130 to 150 watts.
> 811A/812A info from 1970 ARRL Handbook.
>                                  Joe W4AAB
> ----- Original Message -----
> From: "John E. Coleman (ARS WA5BXO)" <wa5bxo2005 at pctechref.com>
> To: "'Discussion of AM Radio'" <amradio at mailman.qth.net>
> Sent: Tuesday, February 21, 2006 8:33 PM
> Subject: RE: [AMRadio] 1930's Old Buzzard Open Rack 
> Transmitter Finally
> SeestheAirwaves! (Long)
> 
> 
> CONGRADULATIONS A JOB WELL DONE!
> I really like the choice of tubes.  I don't know what a T55 is but
> probably one of the special Taylor triodes with 55 watts 
> plate dissipation.
> Probably not a lot different than the 812s but I know that 
> the 812s are very
> good tubes to use in a class C plate modulated rig especially 
> if used with
> 100% grid leak bias or the configuration that Don, K4KYV, 
> uses where there
> is a safety bias supplied thru a diode and the diode becomes 
> reversed biased
> when RF drive causes grid leak bias.  The 100% Grid leak bias 
> DOES make a
> difference in the modulation characteristics of the rig.
> John, WA5BXO
> 
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of ne1s
> Sent: Tuesday, February 21, 2006 2:27 PM
> To: AM Radio Reflector; glowbugs at piobaire.mines.uidaho.edu;
> antiquewirelessassociation at yahoogroups.com
> Subject: [AMRadio] 1930's Old Buzzard Open Rack Transmitter 
> Finally Sees
> theAirwaves! (Long)
> 
> 
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