Hi Nigel, G8IFF/W8IFF
You are right
Aiming the antenna for maximum receiver Sun noise is the best method because the antenna pattern can be affected by some squint angle and not be perfectly aligned with the boom but receiving Noise from the Sun in 2 meters and 70 cm implies a very high antenna gain and a very low overall receiving Noise Figure with a very low Antenna temperature.
By the way at microwave such as 2400 MHz it is possible to receive the Sun Noise using a modest dish diameter even when the Sun activity is low as actually with around 67 sfu at 2800 MHz (10.7 cm)
See here:
http://www.swpc.noaa.gov/ftpdir/indices/DSD.txt
I use this method with my 1.2 meter dish 27 dBi at 2400 MHz and an overall receiving Noise Figure of 1 dB equivalent to a Noise Temperature of 75 kelvin
With the above dish and receiver I actually get a Sun Noise of about 3.5 dB of (S+N)/N wich is easily readible on the S meter or better using an AC Voltmeter connected to the audio output of receiver.
Using a tracking program and aiming the dish for maximum Sun Noise it is possible to calibrate the AZ and EL angle of the control box for the through reference Sun position in the sky.
In addition repeating time to time the above procedure and knowing the actual Sun's sfu it is possible to monitor the state of healt of our receiving system.
By the way without an HEO satellite using 2400 MHz the above procedure is as well a little and interesting Radioastronomy exercise.
Best 73" de
i8CVS Domenico
----- Original Message ----- From: "Nigel Gunn G8IFF/W8IFF" nigel@ngunn.net To: "Greg D." ko6th_greg@hotmail.com Cc: amsat-bb@amsat.org; n0jy@lavabit.com Sent: Thursday, August 13, 2009 2:17 PM Subject: [amsat-bb] Re: rotator questions
How about aiming for maximum receiver noise? That should be even more
accurate.
Greg Wrote: and then adjust the antenna so the shadow falls directly
down the antenna boom.
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