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Re: Source for 1.2g antenna



>Does anyone have a source for a good 1.2g (L Band) antenna that would work 
>well with AO-40?
>
>W4SCO

Referring to my favorite book "P3G to P3D": 10w into an 8-turn helix or 5w
into a 60cm dish-->23 dB SNR.

More recently the Sep/Oct Amsat Journal had two articles on the subject.
Opinions seem to vary on how much EIRP will be needed {23 dBWic-to-33
dBWi}. *Note: dBWic means dB above one watt into an istropic circular
polarized antenna.

I plan to use a 45 element horz. polarized loop yagi that I purchase from
Downeast Microwave, and have 10w at the antenna.  From the mfr spec. ant
gain is 20 dBi, so that would give me 30 dBwi.  BTW the Tx upconvertor will
be a 20w 144/1269 unit from Downeast {est. cost $440} and I expect to lose
3 dB of power in the 100 foot 1/2 heliax coax run.

Of course I could mount the Tx conv. at the antenna, but I plan to use a
60-120w K9EK 2C39 water-cooled amp with this antenna for terrestrial 1296
work.  This arrangement keeps it simpler.  Also, the LO will not be subject
to outdoor temp extremes this way {also, I have conspired to receive one of
the early production units from DEM; it will not be built with an outdoor
case}.

Old antenna Labs and Directive Systems both manufacture helical antennas
for 1.2G.  Downeast has dishes for sale.  If you check Http://www.ntms.org
or Http://www.wa1mba.org
They have microwave links from their web page to suppliers of equip and
antennas.  Don't forget M2 makes 1.2G & 2.4G yagis.

For 2.4G & 10G I am using an 18 inch DSS dish obtained from
Http://www.mcmelectronics.com
with a homemade dual-band feed.

Long answer to a short question ;-)
Ed
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