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Old December 8th 08, 08:38 AM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew
Jeff Liebermann[_2_] Jeff Liebermann[_2_] is offline
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First recorded activity by RadioBanter: Jun 2007
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Default Antenna dimensions?

On Sun, 07 Dec 2008 21:40:38 -0800, John Smith
wrote:

A wavelength at 2.4Ghz will be approx. 12cm, half-wave ~6cm, 1/4 wave
~3cm. (with a very thin wire 1/2 wave monopole-omni-element I find
~12.25cm works for me, element dia. will affect this, as other factors ...)

Anyway, I looked though my old emails for something a friend sent me,
thought if you were interested in the 2.4g fsm, you might be interested
in this, if nothing else, just because the dude is so complete!:

http://www.users.bigpond.com/darren....enna_for_2.htm

You will notice, he uses a plate reflector ...

Regards,
JS


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.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558