Jeff Liebermann wrote:

...
I also noticed that he cut his elements to a precision of 0.1mm. That
would be correct if the boom were an insulator or the elements were
inserted in insulating sleeves. However, since the 10mm square boom
is metal and effectively "shorts" part of each element, the actual
element length includes part of the diameter of the boom, thus adding
approximately 5mm to each element length (not including the reflector
and driven element). A VSWR sweep test would have shown the problem.


I have always used #8 wire as a boom on ghz yagis' (constructed a 7
element once.) Since the boom is at a current antinode (voltage node),
I ignored the boom.

The boom you mention is rather LARGE, give the freqs in question.

One of my next projects is a GOOD VSWR meter for ghz ... unfortuantly,
on the list of priorities here, it is low on the list ... :-(

I have just tended to take the % signal readings on the chans as good
enough, and trimmed my antennas accordingly. I know, this does NOT take
into account the functioning/power-fluctuations/antenna(s)/etc. of the
AP over these ranges ...

But, excellent point, glad you mentioned it ... but you are right, my
elements end up being filed down a bit from the figures the calculator
spits out ...

Warm regards,
JS