Marcel, here are my thoughts:
First, the gain of the antenna and its beam width need to be considered so
that you don't install an antenna with too narrow a beam thereby causing you
to rotate your antenna too frequently. For example, if you want to run
Europeans, you'd like to aim your 20m beam in one location and cover most of
western Europe, rather than have to rotate it to get the north then the
south, right?
So, look at the map projections that give you a good idea of the 3dB
beamwidths at the locations to which you wish to communicate.
Now, if you are not a contester, or desire to search and pounce and have the
loudest signal at the bean heading, choose the highest gain/narrowest
beamwidth antenna. Remember also, that the narrow beam antennas will also
be the most narrow bandwidth beams as well. That's another tradeoff. There
are more.
What about the stacking distances? What about the separation distances
between the 20 and 15 on that tower? Both of these questions can be handled
by modelling the whole tower/antenna configuration with EZNEC of other
modeling programs.
Lots to think about, yes?
73 es GL!
Bill, N3RR
.At 07:27 AM 7/20/96 -0400, you wrote:
>I will be installing stacked Mono Band beams for 20 and 15 mtrs ontop of a
>110 foot H.D. commercial tower for contesting. What kind of beam would
>you recommend and pls give me the pros and cons. Size is no object.
>Would like as much gain as possible. I am now using a Mosley CL36 at 60
>feet which I will use on a 70 foot tower as a general short skip antenna.
>Thanks for your help
>Marcel Gervais VA3MG
>
>
>--
>Marcel Gervais FreeNet be130
>Amateur Radio Call VA3MG
>Home tel 613-830-5287 Home fax 613-830-1579
>
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