Look carefully at the design of ANY stacking switch. Many use a
single fixed 2:3 turn radio autotransformer (2.25:1 impedance
ratio) as a compromise for both two antenna and three antenna
stacks. In a 50 Ohm system this results in "best case" SWR of
1.13:1 with two antennas and 1.33:1 with three antennas.
There are techniques that will allow proper matching (switchable
taps or multiple transformers) with either two or three antennas
however, they are more expensive than the compromise designs.
... Joe Subich, W4TV
> -----Original Message-----
> From: email@example.com
> [mailto:firstname.lastname@example.org] On Behalf Of Terry Gerdes
> Sent: Monday, July 31, 2006 10:05 AM
> To: email@example.com
> Cc: TOWERTALK@contesting.com
> Subject: Re: [TowerTalk] Stacking tribanders (SteppIRs)
> Hi Howard,
> Thanks for the replay. Does the Comtek switch work better than
> the Stackmatch? What I see here is the lower and mid antennas
> have flat SWR when running standalone but when I put them into a
> stack, the SWR jumps high enough to get close to dumping the Alpha
> amp off-line. Does the Comtek switch provide a better match?
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