[amsat-bb] Re: Antenna question

[James Duffey]

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On Sep 21, 2008, at 5:22 AM, Michael Heim wrote:

> My question is, to simplify mounting  to a small diameter insulated  
> boom, could such an element be placed "laying down", so the element  
> could be better supported by drilling 2 holes in the boom?

Michael - W7ZOI built one of the WA5VJB Yagi antennas for 2M using a  
driven element oriented just as you describe. He said it worked just  
fine.

I think you want the long part of the driven element to be in the same  
position in both antennas, but you may want to model it to verify  
this. The position is not too critical for 2M.

In Kent's antennas, the position of the driver from the reflector  
largely determines the impedance of the antenna, and the position of  
the first director from the driven element largely drives the SWR  
bandwidth. The gain sort of comes along from these positions for the  
three element beam and when there are more than one directors, these  
pretty much determine the gain.

They are nice antennas aren't they. I have built and used a half dozen  
for various bands and they all work great as built. I use them at the  
home station for terrestrial and satellite use, and in the rover. Now  
if Kent would only make some longer boom designs available. - Duffey
--
KK6MC
James Duffey
Cedar Crest NM