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Re: First S band copy



I would like to pick up on Cliff's observation about squint.
An activity that I have been involved with in recent weeks has 
been to plot the pattern of the helical beam on the S2 
downlink, relative to squint angle. 
In summary the results indicate that the best results are 
obtained when the squint angle is less than 30 degrees.
Magnificent signals are received when the squint angle is < 10
degrees. 
Therefore I would strongly suggest that you PLAN your activities
based on SQUINT angle at your respective QTH,s
The attitude determined on Orbit 243 was Alon 10.2, Alat 1.5
The reason I say PLAN is that for my QTH in VK5 for the 
following week or so we see a cyclic 3 day pattern (approximation). 
One of those days is excellent the other two would be classified as
are poor. The good day has squint angles down to 7 degrees,
whereas the other two are for the majority of the pass much
greater than 30 degrees. In some cases greater than 90 degrees.
What is the bottom line.
Use your tracking program to ascertain when the squint at your 
QTH is less than 30 degrees. 
Optimise your uplink activities for those periods.
Spend a little time monitoring the received beacon strengths for
various squint angles to get a feel for the downlink performance.
A small modicom of planning up front may well help to negate 
frustrations building up when the signals today were not as good 
as yesterday. Saves ripping the system down looking for a 
non-existent fault. 
Finally a personal request from an avid telemetry recorder and
on behalf of other telemetry enthusiasts obtaining data for the
AO40 archive. Please remain clear of the respective beacons.
Every time someone swishes a carrier across the beacon is a 
potential failed CRC's telemetry block. Every telemetry block
IS IMPORTANT for the future life and well being of AO-40.

de Colin VK5HI 
   
----- Original Message ----- 
From: "Clifford Buttschardt" <cbuttsch@slonet.org>
To: <wb4mle@mindspring.com>
Cc: <amsat-bb@AMSAT.Org>
Sent: Saturday, May 12, 2001 1:22 AM
Subject: Re: [amsat-bb] First S band copy


> It certainly looks like most of us have not found peace with the notion
> that "squint" needs to be paid attention to!     Cliff K7RR


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