-----Messaggio originale-----
Da: Bill Vogler <vogler@innercite.com>
A: amps <amps@contesting.com>
Data: sabato 31 luglio 1999 1.07
Oggetto: [AMPS] explain this one
>
>I am at a loss for an explanation on this one. When switched to 10
>meters/AUX, the 160 meter capacitor in question is out of the circuit. I
>checked the bandswitch wafer(s) and there is not a short or problem,
>everything checked out like it should have (or at least I think).
What do You mean for "out of the circuit", is it only connected ta a
dead pin of the wafer switch, or some other component (of 160m) you
extimated out of the used (on 10) circuit anyway is connected to it ?
>The 160 capacitor is connected to a beefy wire that is connected between
>the wafer and a side wall. This lead is long and goes across the top of the
>variable Load capacitor in the PI/Tank circuit.
On load capacitor the impedance is low then voltages are low and capacitive
couplings are a minor problem.
>I might also mention that
>the tube is running much hotter at 10 than on the other bands, the outer
>case above the tube is uncomfortably hot.
Check output power and power consumption on different bands, You'll have a
much better idea of the efficiency than with thermal feelings.
>My only guess/explanation is that there some type of coupling going on and
>the only way this could happen is at a very high frequency.
I bet 99.9 % it wont be anything like that, anyway:
any self oscillation of the magnitude you report (to heat a good RF Hi
current cap it's not so easy) should noticeably influence PA idle current.
Check if PA idling is the same on all bands.
If I were you I'll check wiring and switches again, may be with a lens or an
Ohmmeter were possible. I'm sure the problem is much less complicated
than you think. Check that capacitor value and also Amp on 160m to verify
if it works correctly.
73,
Mauri I4JMY
> Did I inhale
>too much of the burning capacitor? I feel like changing my call to
>kr6ack!!!
>
>73s
>
>Bill, w6qd
>
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