[TowerTalk] High enough for a small beam?

Derek Cohn/WB0TUA vibroplex at mindspring.com
Sat Nov 20 07:22:06 PST 2010


Hi Everyone,

I'm starting on my first tower project and looking at various options:

* U.S. Tower MA-40 in my back yard
* Glen Martin Rooftop tower

For a beam, my options are:

* Mosley TA-33 (not jr.) I already have
* Optibeam OBW10-5 10 Element wirebeam

The U.S. tower MA-40 is my first choice for tower but I live in an inner-ring suburb and am tangling with the city on the permit process (what a surprise).

My question is about the viability of using a rooftop tower.  The peak of my house is 24 feet plus change.  An 8' or 9' would put me right around 33' which I think is the magic number (1/4 wave) above ground on the lowest band these beams are designed for.  Is this "high enough" above ground so that the beam will be properly resonant and that it will be effective?  I know that on top of the MA-40 is a better choice but if the city fights back hard, is it worth putting up at 32' or 33'?  

One last question, if I get shot down with an 8' or 9' tower, I see that Glen Martin also has one that is 4 1/2 feet.  That would put me right at 29 feet above ground.  It would be significantly more low profile but does the 4' that I'm losing with option significantly degrade the performance?

Thanks for any help you guys can give me,

Derek Cohn
WB0TUA


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