[CQ-Contest] SO2R Coax Stub location; outside?

[Jukka Klemola]

Exactly!

One detail sharpened:
double stub separation is optimal at 1/4 wave separation on the harmonic
frequency.
Please note 1/4 waves is typically 1/8 waves on the fundamental frequency.
The 40 pass 15 reject dual stub separation, that is 15 meter's 1/4 equals
1/12 waves on 40.


Exact placement of stub is less critical than (not)having the stub in the
station construction.
Flipping the thought: it is better to have a stub than try and operate
2radios without stubs.


73,
Jukka OH6LI


ma 24. helmik. 2020 klo 14.29 Jim Brown (k9yc at audiosystemsgroup.com)
kirjoitti:

> On 2/23/2020 11:49 AM, wc1m73 at gmail.com wrote:
> > Can anyone confirm that stubs work best 1/4-wave from the transmitter?
>
> That's a serious oversimplification. Here's the detailed answer. It ran
> in NCJ a few years ago.
>
> http://k9yc.com/LocatingStubs.pdf
>
> And here are slides for a "big picture" overview talk I gave at Visalia
> last spring.
>
> http://k9yc.com/Multi-Station.pdf
>
> The executive summary: spacing between stub and output stage always
> matters, and what's best depends on the output network. Spacing between
> stub and antenna matters IF the antenna is NOT resonant on the harmonic,
> but does NOT matter if the antenna IS resonant on the harmonic. And two
> stubs, 1/4 wave apart at the harmonic frequency is much better than a
> single stub.
>
> 73, Jim K9YC
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