[VHFcontesting] microwave loop boom

Zack Widup w9sz at prairienet.org
Mon Oct 7 23:57:27 EDT 2002

I don't know of any reason why you can't use a square boom.  The only
thing is that the lengths of the elements may need to be adjusted
somewhat, as more boom metal is closer to the element where it attaches to
the boom.  Most people like to stick with the design they know works,
instead of trying to redesign it because of boom detuning effects.  I
don't know how drastic those may be in this case; it may be insignificant.

I find loop yagis to be tremendously tolerant of bent elements. When I
take mine on a portable operation, I always manage to get some elements
bent up in the car and then just rebend them when I have the antenna on a
mast. I haven't noticed any degradation in performance.

73, Zack W9SZ

On Mon, 7 Oct 2002, Rick R wrote:

> Can someone help me understand why microwave loop antennas are made on a 
> tubular boom rather than a square-tube boom? I am in the process of 
> improving some of my rover microwave antennas, and will be restoring the 
> length of the 903, 1296 and 2304 loopers back to their full sizes (I have 
> been using half of them for several years, figured this is the easiest and 
> cheapest way to add db for both xmt and rcv). When I bought these loopers, 
> they came with a small piece of square tubing mount and aluminum plate. I am 
> also going to remount the antennas to the main mast using a piece or 2 of 
> rectangular cross-boom to support all the loops, as it makes the alignment, 
> drilling, and parallel mounting of all the loopers easier. I was just 
> curious as to why the ease of using a rectangular boom for these loopers is 
> not the standard? Would it severely degrade or affect the antenna/gain 
> pattern?
> Thanks...rr.. K1DS

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