[TowerTalk] stubs for the SO2R setup

[Tom Osborne]

Hi Felipe

I have some stubs here and they don't seem to be affected so much by where I 
put them.  I put mine right on the antenna switch so that they can be used 
by either radio when running SO2R.

I have a 2-way switch for every antenna that comes into the shack, and the 
output of each 2-way switch goes to 2 different antenna switches----1 for 
each radio.  I have my stubs connected right where each antenna goes to the 
2-way switch.  73
Tom W7WHY


> Hello,
>
> I am trying to make a set of stubs to be used on my SO2R station setup.
>
> Those stubs should be plugged to a six pak box.
>
> When I measure the 1/4 wave shorted 40m stub, plugged directly on the
> MFJ-259, with a dummy load paralelled by a tee connector, I can see the
> nulls on 14 and 28mhz.
>
> When I plug that stub and that very dummy load on the six pak 40m port,
> things change. Nulls go to 12.9mhz and 24.9mhz.
>
> The obvious explanation is that the length of cable between the amp
> output and the six pak input is being added to the stub, right?
>
> If so, also seem obvious that I should have the same length of cable
> between both of the amps and the six pak, right?
>
> If so, I should take this length into account, and things will change if
> I turn the amplifier online, offline, right?
>
> If so, how can I deal with it in situations where I have multiple stubs?
> For example: on 40m, I plan to have 2 1/4 wave shorted stubs nulling 14
> and 28mhz, and the 1/6 + 1/12 wave for nulling 21mhz
>
> If so, I have quite a terrible problem in hands.
>
> 73 and thanks in advance for your advice,
>
> Felipe - PY1NB
>
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