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

Alan ve4yz at mts.net
Fri Dec 26 09:44:54 PST 2008


Hi Guy and the group... 

Here is Pete's current dual band yagi which I believe you are referring to

http://www.gulfalphaantennas.com/Product%20Page%202M%2070CM%20sat%20yagi.htm
l

As Joe mentioned, the craftsmanship and material quality is first class.  I
am also the owner of the older versions shown in the first couple of
pictures here:

http://picasaweb.google.com/ve4yz.alan/VE4YZ#

where I ran a pair of them with M2 matching tees and no mast mount preamps (
but with the internal preamps in the FT847 ) but with AZ and EL control.

This was satisfactory for me for a while and worked well especially on the
SSB sats, FO-29, VO-52, AO-7.  On FM AO-52 and SO-50 there were fads due to
lack of polarity control.  GO-32 and ISS TX are so strong that polarity
control was not an issue.

However, I eventually moved to abbreviated KLM's ( due to tower limitations
and roof clearance ) with polarization control and Landwehr preamps shown in
the later photos.  The improvement was huge!  I have the KLM's and HyGain's
full length at 2 other locations and the performance is a little better but
not a huge an improvement as going for no polarity control to the switchable
polarization.

Here... http://www.mts.net/~ve4wsc/photogallery/tour3.htm  M2/KLM
And here... http://picasaweb.google.com/WinCube.Winnipeg/GroundStation#
HyGain

The GulfAlphas are in storage in the garage rafts and are ready for use at
Field Day and other events.

At my QTH I think I am an example of what is often heard in ham circles -
invest as much as you can on the antenna, on feedline and preamps.  At home
I went from a rotator mounted Arrow to the GulfAlphas to the KLMs over the
course of about 4 years.  They all worked.   But they all worked differently
:-)   Unfortuantely this is a case of $$$ being a big part of the solution.


... Alan


> -----Original Message-----
> From: amsat-bb-bounces at amsat.org 
> [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Gary "Joe" Mayfield
> Sent: December 26, 2008 7:28 AM
> To: 'Guy Brauning'; amsat-bb at amsat.org
> Subject: [amsat-bb] Re: Gulf Alpha Antenna Model No.2M 70CM 
> Sat. (DualBandAntenna)
> 
> Guy,
> 
>      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!
> 
> 73,
> 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
> BandAntenna)
> 
> 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!
> 
>  
> 
> Guy 
> 
>  N3SCR
> 



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