[AMRadio] Filament Voltage

[Bill Smith]

Beware the filament meter.  Are you sure the voltage is going up, or is the
meter affected by RF?

----- Original Message -----
From: "Dan Hall" <kj7fx at tdn.com>
To: <amradio at mailman.qth.net>
Sent: Sunday, March 24, 2002 4:32 PM
Subject: [AMRadio] Filament Voltage


> Greetings:
>
> I have very poor filament voltage regulation on the Gates BC1-J. The
> transmitter is designed with a rheostat on the front panel to set the
> voltage to 10 volts. Of course it is designed to run around the clock. If
I
> set the voltage at standby to 10 (filaments glowing, all plate voltages
off)
> when I move to transmit the filament voltage drops to just over 9V. The
best
> efficiency is around 63% (2075 VDC, .380 A and 500 watts out). Leaving
> everything else alone I then crank the filament voltage up to 10 volts and
> get 73% (2050 VDC .400 A and 600 watts out).
>
> The problem is that when I key up, the filament voltage soars to about
10.75
> volts.
>
> Now, should I run the tubes at 9 volts in transmit and 10 at standby or 10
> volts in transmit and 10.75 at standby?
>
> Thanks
> Dan
> KJ7FX
>
>
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