[TowerTalk] connecting more than one stubs

[David Robbins]

to do more bands like that you won't be able to just short and unshort the ends, you will have to actively switch the stubs for each band in and out of the circuit.  you could do this with a remote antenna switch, but you have to keep the connections short and may have to shorten the stubs a bit so the impedance at the connection point to the coax is proper.

Nov 20, 2012 11:58:24 PM, sv1dpi at otenet.gr wrote:



Hello to all
I am trying to make stubs for my club and i need your help.
We have 2 ant: one is x7 (10, 15, 20) and the other one a exp14 with 40m
kit (10, 15, 20, 40).
What i have done until now is to follow the most of k2tr and k1ttt
advices and make 2 stubs, 23 feet each. So we can change between bands
just sort or unsort the end of the stub in every antenna. Te bad thing
is we have not additional isolation form stubs on 10 (11'6" missing) and
on 40m (15'3" and 7'8" are missing also).
My questions now...
1)Do i need to have a minimum distance on 10m between 11'6" and 23' stubs?
2)It is not so clear to me how i should connect the additional 40m
stubs. Minimum distances agn?
3)Trying to keep things simple as the change from band to band is manual
right now, my thought is in x7 (10, 15,20) to have 2 T-connectors. So on
10m we connect 23'open and 11'6"open. On 15m we short the 23' and change
the 11'6" with another shorted 23' for additional attenuation. And on
20m we have the 23' open and 11'6" shorted. Is my thought ok? Do i need
to avoid anything?
4) Probably for the exp14 (10,15,20,40) i need to put 3 T-connectors (to
cover 40m), so things are not so simple (!) or i am missing something?

73 Kostas SV1DPI





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