[AMRadio] Filament Voltage

[Dan Hall]

Don, Steve and Bill:

Thanks for the help. It's actually kind of funny Don. The truth is that I am
an electrician. Thirty four years now......and I wired the house. Hi Hi Hi.
The line voltage only drops about 2 volts line to line when I go into
transmit. I put my fluke on the filament pins of the modulator tubes (full
bias) and it did drop the voltage way too much when I put it in transmit.

I think it is something I did wiring the transmitter not the house. Hi Hi.

I'll go over it again and think on it over night. That usually reveals
something I've overlooked

Thanks
Dan
KJ7FX
----- Original Message -----
From: "Donald Chester" <k4kyv at hotmail.com>
To: <amradio at mailman.qth.net>
Sent: Monday, March 25, 2002 3:45 AM
Subject: Re: [AMRadio] Filament Voltage


>
>
>
> >From: "Dan Hall" <kj7fx at tdn.com>
>
> >I have very poor filament voltage regulation on the Gates BC1-J.
>
> First, verify the filament voltage using an external meter.  RF may be
> affecting your reading.
>
> If the primary voltage is indeed varying that much, I suspect you have a
> problem with the electrical wiring in your house.  I assume you are
running
> it on 220 volts.  The kind of load you are talking about shouldn't affect
> voltage anywhere near that much.  Check your house wiring, or have an
> electician do it if you are not completely confident in your ability to do
> it yourself.  Left unattended, problems like that have been known to
result
> in house fires.  Do your room lights flicker when you transmit?
>
> If you are running it off 110 volts, poor line voltage regulation may be a
> problem.  My transmitter runs off 110, and I had the same problem
(although
> even on 110v my filament voltage didn't sag that much).  I rewired it so
> that the low power stuff including the filaments runs off one side of
> neutral, and the HV power supplies run off the opposite side.  Now, when I
> kick on the high voltage, the filament voltage kicks UP slightly.  With
this
> arrangement, with both circuits sharing the same neutral wire, the voltage
> drop from the HV primary current adds to the output voltage on the
opposite
> leg. The final tubes like that little boost in filament voltage and grid
> drive when they are called on to deliver power.
>
> Don K4KYV
>
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