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:
Gain per unit length of boom
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October 19th 04, 08:37 AM
Ian White, G3SEK
Posts: n/a
wrote:
I did not want to choose a curve that matches my modelling which you
can
when presented with three different curves all of which are formulated
at different
times by different people. I would have thought that the advent of NEC
would
render these curves redundant !
The plot of many individual yagis does confirm the general idea of gain
being roughly proportional to boom length, and that is a very important
thing to understand.
Note that this is only for long-ish yagis with many elements. For yagis
of 2-3-4 elements on a short boom, the first few dB of gain come very
easily. Beyond that, the data points settle back towards the long-yagi
trend line.
To increase the gain by 3dB, you need to either double the boom length
(and redesign the yagi, obviously) or else stack two of the same
yagis... and either way, in practice you'll achieve slightly less than
3dB.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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