Mel,
The nature of your questions suggests you should probably did into the
literature (e.g., the ARRL Handbook) a bit before moving forward too far
with construction. To start, you should probably check out how to compute
plate load impedance for class B linear service, and also the circuit
parameters that affect the loaded Q of a tank circuit. Without an
understanding of these things, you run the risk of having an amplifier that
won't deliver the kind of service you're hoping for.
73,
Jim W8ZR
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Mel
> Sent: Tuesday, May 28, 2013 8:56 AM
> To: amps@contesting.com
> Subject: [Amps] Tuned Output Network for gs35-b
>
> Greeing to all,
>
> I have an interest in building an amplifier around a GS35-b Triode tube, I
am going to make
> this a multi-band amplifier. I have the complete Tank circuit from a Drake
L4-b and, I am
> trying to use this as my output network.
>
> As with any project, there are some issues, the band switch has been
repaired because the
> contacts that are in use for the 10 meter band have been fried. I
serviced the switch and,
> indexed the useless contacts out of the line of fire; this left me with
the ability to only
> support 4 bands. 80 meters thru 15 was a complete no-go.
>
> I dumped the vertical 80 meter coil and re-worked the rest of the tank
coil and switch; I
> added a tap for fewer turnes at 10 meters, used the old 10 meter tap at
the 15 meter switch
> etc. Coming to the end of the coil, where the 40 meter tap was, that tap
is now connected
> to the load gang. In position "10 m" all the taps are shorted out except
2 turns; in the "40 m"
> position, none of the taps are shorted by the switch and the whole coil is
active in the
> network.
>
> I am working with a MFJ-259 Analyzer (the first model) and, with a Plate
load of about
> 2500 ohms, (planning on running about 4000 volts at 500 mills) all ham
bands fall into
> tuning range.
>
> Now that you have the setup, here's the question: "For a given frequency,
if your circuit
> tunes with more capacitance (Tune) in one position but also tunes in
another position with
> more turns on the tank coil but less Cap on the Tune side, what could be
said about the coil,
> the, Q and which position for that "Given Frequency" would be best to tune
at"?
>
> Mel
>
> koØm
> .
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