[TowerTalk] stacking different antennas

KC4HW jimjohnson at alaweb.com
Wed Mar 21 22:16:58 EST 2007


When you are talking about different antennas, exactly what could that mean....

5el/20M and a 4el/20M or 

different multi-band antennas

or what??


On 10 Mar 2007 at 9:48, Michael Keane K1MK wrote:

> At 09:20 PM 3/9/07, Cqtestk4xs at aol.com wrote:
> >I know there may be a phasing difference, but I will be running
> >identical  lengths of coax to them, so I'm not sure where the phasing
> >difference that guys  mention in this stacking comes from.
> 
> No, that's not it. The phasing concern with stacking dissimilar 
> antennas is that the "zero phase" point the antennas will be in 
> different positions horizontally. That requires an additional section
> of "delay line" be inserted into the feed path to one or the other
> antenna to bring them into phase.
> 
> The phase difference can be modeled or it can empirically determined
> (see:  <http://www.arraysolutions.com/Products/dissimilarants.htm>).
> 
> 73,
> Mike K1MK
> 
> Michael Keane K1MK
> k1mk at alum.mit.edu
> 
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Jim/KC4HW
http://www.AlabamaContestGroup.org
http://www.AlabamaQSOParty.org (June 2nd and 3rd, 2007)




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