[CQ-Contest] Plesant change / multiple antennas

Tom W8JI w8ji at w8ji.com
Sat Oct 22 14:33:08 PDT 2011


> have problems with this.  The thing is I have two different beams  (A4S 
> and TH 5 ) on seperate towers.
> Up to this point I can feed  the TH5   at  75 feet  alone  or  the th5 
> and A4S  (at 35 ft ) together.
> Not the A4S alone yet.   With both beams  swr goes up  a bit but rigs 
> antenna tuner takes care
> of it.  I am thinking I can live with this ?

Bob,

It's better to either match things closely and tune a marginal amp properly, 
or seriously over-couple the amp to reduce efficiency and use a much larger 
amp than required (then you have one power knob to adjust).  Otherwise you 
would be adjusting the radio or amp all of the time, or splattering 
needlessly.

To maintain impedance when paralleling systems, it would be better to use a 
good stacking box to run multiple antennas. Remember, legal output power is 
actually forward power MINUS reflected power. It is never forward power 
alone unless reflected is zero.

Doing something marginal, that makes others suffer or is rough on our gear, 
is always easy and cheap.
:-) Using your tuner is fine though, if you really want to retune every time 
you flip the dual antenna or single antenna switch.

73 Tom 



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