Re: [amsat-bb] AO-40 ordering antennas, downconverters

["kgshutt" <kgshutt@xxxxxxx>]

Hi Tony,

A few comments:

1.  Gain is not that important.  With the AIDC 3731 you will have excessive
gain and will need to use an attenuator to prevent overdriving your receiver
and reducing dynamic range.

2.  How are you going to illuminate the dish?  Helix feeds seem to be better
for an offset dish.  A patch feed is often better for non-offset dishes.
Bob's systems use either a dipole feed or "provide your own".  Either a
helix or patch is required to obtain circular polarization.  Another
critical decision!  I'm not sure what feed system is provided with the N3IYR
dish.  Just make sure the feed properly illuminates your dish.

3.  I have several TSI systems.  All perform very well.  Great performance /
price ratio.  The only problem I have experienced with the TSI systems is
temperature stability.  They drift a lot with ambient temperature.  Doppler
is also +/- 20 hrz so this may not be such a big problem.

4.  The pointing accuracy of the Yaesu G5400/5500 rotor system should be
adequate for a 3' dish.  My CD-45 azimuth rotor is marginal.

Good luck with your project.  Let me know what you decide to do.

73 de Ken - K5GUU

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