[amsat-bb] Re: Gulf Alpha Antenna Model No.2M 70CM Sat. (Dual BandAntenna)

Gary "Joe" Mayfield gary_mayfield at hotmail.com
Fri Dec 26 05:28:21 PST 2008


     I have the previous version of the Gulf Alpha dual band.  We use it at
field day every year and it performs well.  Your idea to add the pre-amp is
wise as it is a little short for some of the UHF downlink signals.  

     You may also want to plan for some classic mode J de-sense issues which
aren't really a factor of the antenna as much as a reality of listening on
the third harmonic of your transmit signal.

     On the whole it has been a great antenna, and that sucker is built like
a battleship.  I wish he had a larger line of antennas as he builds a VERY
solid product.  I believe Gulf Alpha is a one man shop so there may be some
lead time as well, but definitely worth the wait!

Joe kk0sd

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Guy Brauning
Sent: Thursday, December 25, 2008 7:44 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Gulf Alpha Antenna Model No.2M 70CM Sat. (Dual

Hello and thanks for reading this.  I am looking for some "Owner Experience"
before making a decision about buying one of the Gulf Alpha dual band
satellite antennas.  I know the antenna is a compromise compared to a pair
of circular polarized yagis; however, I am looking for a less expensive
alternative for a basic 2M/70CM base set-up. My only experience with the
satellites has been with handheld/portable radios (FT-60R and FT-817ND) and
the Arrow and ELK handheld antennas.  My guess is that the Gulf Alpha dual
band satellite antenna (installed above obstructions and with an AZ rotator
/ low loss feed lines / and a 70CM mast mounted pre-amp) would be comparable
if not considerably better than the handheld Arrow/ELK for FM work on AO-51
and SO-51 (for passes at or below 40 degrees max elevation) but I would also
like to work some of the linear sats on SSB/CW and I don't know if the
antenna would meet that need. (I already have a 2Meter all mode in addition
to the FT-817 as well as a refurbished CD-44 rotor.)  If this antenna would
support reliable CW/SSB contacts on the linear satellites, it would be a
good fit.  I would install the antenna at approximately 25 feet in height,
leave it fixed at 15 degs elevation using the supplied mast mount, and
rotate it with a CD-44 rotator.  I plan on using LMR-600 coax for the 432
run and LMR-400U for the 2 meter run (Total length for each run about 30 -
40 feet).  I would also use an AR2 mast mounted 432 preamp and Polyphasers
at the shack entry with appropriate jumpers (best loss specs vs. needed
flexibility) from the Polyphasers to the radios.  Radios would be a Yaesu
FT-290R MKII (2 MTR All-Mode) and a Yaesu FT-817ND for 432.  I'm looking for
someone with experience using the Gulf Alpha to let me know their opinion of
how well the antenna might play given my anticipated installation specifics.


Thanks for your help!





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