2.4GHz dipole antenna improvement
 

Hi, following on from the disastrous experience of using 2.4GHz for
local purposes, where the signal was crap and the microwave knocked out
the system, I finally found the time to improve the system. What I did
was to take the design for a Quad antenna from

http://www.qsl.net/oe3mzc/antenna.htm

and guessing that the existing "Rubber Duck" antenna was a centre fed
1/2 wave dipole, to construct two 1/4wave long cylinders (from brass
shim) which were adjusted to be a good fit over the existing receiver
dipole ( one 8.5mm id the other 9.5mm id) and to solder each centre
point of the quad, which in the original are connected to an N type RF
connector, to one end of each 1/4 wave tube. The assembly is planar, not
orthogonal. The gap between the two tubes is about 2.5mm. The resulting
assembly slips over the existing receiving aerial with an easy fit. The
results were surprising. I guess the received signal is improved by up
to 10db!! and is of course directional. The microwave no longer knocks
out the signal. I built a few of these assemblies using 2.5mm solid wire
and 1.5mm solid wire(2.5mm t & E!) and could not tell the difference. I
also found that adding one of these assemblies to a window in the
transmission path also improved the received signal level. I'd be
interested to hear if anyone else has tried this approach.

Regards
Capitol