Tom, If you use smaller wire you can get a little more inductance and other
than a remote possibility of a resonance in one of the bands, there
shouldn't be any problem.!! I did that on an SB200 to reduce the fil v a bit
and had no trouble at all. I rewound the choke using 18 ga. wire rather than
14. But of course what you use will depend on the current capacity needed.
carl / kz5ca
----- Original Message -----
From: "Thomas R. Williams" <n2cu@magtrol.com>
To: <amps@contesting.com>
Sent: Tuesday, June 15, 2004 1:00 PM
Subject: [Amps] Filament Choke mod
The filament voltage on my Drake L7 is 5.25 V, which conventional wisdom
says is too high by about 0.3 V. I'd like to avoid placing a series resistor
in the primary of the filament transformer since the antenna relay gets
powered by another secondary on the same transformer and I'm building in a
relay speed-up circuit - I need the extra voltage for that.
The filament choke appears to be wound with 11 AWG formvar wire. I
calculated the additional resistance needed to drop the voltage and found
that rewinding the choke with 14 AWG wire would do the trick, as far as
resistance goes. If I use the same number of turns, should I be concerned
about the inductance being a different value due to the wire size? Any other
things to consider looking at?
73,
Tom N2CU <><
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|