>
> ...
>
>> -attenuation almost doubles in dB compared to one stub
>>
>
> Yes.
>
>
>> --> I have been building only double stubs nowadays.
>>
>
> Me too.
>
> Another point. When you have done this amount of suppression, you will
> likely begin to find other sources of 2nd harmonic, as W3LPL recently
> observed (perhaps on another reflector), AND you may also find leakage
> paths in your antenna switching system. I recently replaced a vintage Six
> Pack with a 6x2 sold by 4O3A. I measured crosstalk in the 4O3A unit before
> installing it and the Six Pack after removing it and found the 4O3A unit
> had more than 20dB better isolation on 20M.
>
Recipe for this:
http://www.yccc.org/Articles/K3NA_stubs.pdf
Eric has done a wonderful job describing the ultimate stub system.
But the stub construction method is critical to build; personally I liked
K2TR stubs better.
At OH0V, we have built the system according to Eric K3NA switching
principles and K2TR(K1TTT?) stub principles.
> In hopes of picking up another 6-10 dB of isolation, I am also planning to
> replace some of the random vintage patch cables in my station with newly
> made jumpers using high quality RG213 and Amphenol 83-1SP connectors.
>
>
Well .. some just simply go the extra mile !
> 73, Jim K9YC
>
73,
Jukka OH6LI
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
|