Mike,
Sorry .. too little data.
I ran into same situation.
My solution is now to remove all diodes and transistors from the system.
Those I cannot remove, I RF filter with capacitors and ferrites. Both ..
capacitors and shaped iron powder products .. also some inductors.
LEDs are diodes.
Do you have anything else like an automatic band pass filter in the system
in addition to the stubs?
Do you use an external power meter?
Do you have an amplifier in the system?
Is the stub between the radio and amplifier or between amplifier and
antenna?
Do you use an antenna switch that incorporates relays?
One other book you should glimpse is Dave K1TTT's Building a Superstation.
73,
Jukka OH6LI
2015-09-08 4:07 GMT+03:00 Mike Smith VE9AA <ve9aa@nbnet.nb.ca>:
> This is about coax stubs.
>
>
>
> Sent this earlier to "Towertalk" then I thought perhaps it was better
> suited
> to contesting.
>
>
>
> Reposting, with some edits:
>
>
>
> I've seen the K2TR stubs, K1TTT page and have recently bought the FB book
> by
> W2VJN
>
> Today, for a change, I had a little spare time so built 2 stubs, but lets
> just concentrate on one.
>
> It was supposed to be for the 40m transmitter (Radio A).
>
> I will add Radio A (transmitter) is using a multiband vertical.
>
> Radio B (receiver) is attached to a multiband horizontal dipole (ZS6BKW) in
> case it makes any difference in my question.
>
> I see a signal of roughly S9 or S9+ 20/40 on the receiver (varies per band
> &
> harmonic)
>
>
>
> I roughed out the length, attached a T and a 2nd antenna switch (a la VA2UP
> method) (which I'll only use for stubs), trimmed it with my AA-230pro
>
> and when it's inline (parallel to my primary antenna switch) I see no
> difference at all on 20m or 15m on my 2nd receiver when the stub is in or
> out of line
>
> NONE. Like, not even a titch ESP hopeful. (hi)
>
>
>
> I presume this is a type 1 stub (shorted 1/4WL type, x velocity factor)
>
>
>
> Thinking I had done something wonky, I made another stub from different
> coax..same result.
>
> Later I made one up for 20m - same result. No change whatsoever in the
> received signal harmonic(s) on the receiver.
>
>
>
> Anyone been down this road?
>
>
>
> Too close to rig?
>
>
>
> Interaction from my T and 2nd antenna switch? Gremlins? Wrong method using
> the AA-230 pro maybe? I am close to that 23' mark on the 40m one.
>
>
>
> de Mike (SO2R hopeful) VE9AA
>
>
>
>
>
> Mike, Coreen & Corey
>
> Keswick Ridge, NB
>
>
>
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>
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