I would bet if you were to do some careful calculations, there would be a
resonate circuit on or about 10 meters. The circuit would be formed by the
connecting wire and cap leads, and the capacitance of the caps.
Interesting to say the least!
Just when someone thinks they have ALL the answers......
73 and keep us informed on the progress!
Jim W7RY
-----Original Message-----
From: Bill Vogler <vogler@innercite.com>
To: amps <amps@contesting.com>
Cc: philk5pc@tyler.net <philk5pc@tyler.net>; w8ji@contesting.com
<w8ji@contesting.com>; Peter_Chadwick@mitel.com <Peter_Chadwick@mitel.com>;
i4jmy@iol.it <i4jmy@iol.it>
To: <amps@contesting.com>
Date: Wednesday, August 04, 1999 5:22 AM
Subject: Re: [AMPS] Explain This one
>
>> You'd have to see some LK-500 wiring and parts values to believe it
>> Peter. Nothing would suprize me.
>>
>> Without seeing the wiring and the bandswitch, anything could be
>> going on.
>>
>>
>> 73, Tom W8JI
>
>Ok Folks -
>
>I think I have the answer on this problem. To quickly recap I'm burning a
>160 meter padding capacitor on the LOAD (antenna) side in the tank circuit
>on my LK-500ZA when transmitting on 10 meters. The consensus was that there
>was two possibilities:
>
>I) Bad wafer on the bandswitch and the 160 meter padding capacitor was
>actually being connected to the circuit.
>
>II) Inductive coupling ( I think this what Phil, k5pc was referring to as
>"Autotransformer"). The heavy gauge leads of the of padders were parallel
>and in close proximity to the turns of the 40-160 meter tank coil.
>
>I decided to try an experiment. I went into the amplifier and disconnected
>the padders from the wafer on the bandswitch. I kept the leads in the same
>position, parallel to the coil and made sure that it was not making contact
>with anything, just hanging in the air.
>
>My assumption was that if the capacitor didn't burn, that it was probably
>due to the bandswitch and if it did it was inductive coupling. I tuned the
>amplifier on 10 meters into a dummy load and the capacitor started to fry
>like an egg.
>
>I'm assuming that it is inductive coupling. I am going to rebuild the
>padder portion of the tank circuit. I am going to relocate the capacitors
>such that the leads due not lend themselves to couple energy from the tank
>coil (i.e., I am going to keep the wiring away from the coil).
>
>Thanks for all your help and I'll let the group know how it turns out.
>
>
>73s
>
>Bill, w6qd
>
>--
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>
>
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