[AMRadio] 1930's Old Buzzard Open Rack Transmitter Finally

crawfish crawfish at surfmore.net
Tue Feb 21 22:07:21 EST 2006

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)

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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