The clock is important to be as accurate as possible. Also make sure that you are using as accurate a latitude and longitude setting in Observer setup. Even just using two decimal places after the Lat/Lon value may not be adequate especially on high passes even if the clock is accurate. These two settings will make all the difference.

Tom Schuessler, N5HYP EM12ms

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Message: 10 Date: Fri, 24 Apr 2020 10:13:44 -0500 From: "Alan" wa4sca@gmail.com To: "AMSAT-BB" amsat-bb@amsat.org Subject: Re: [amsat-bb] Uplink Calibration in SatPC32 Message-ID: 000201d61a4a$f318f710$d94ae530$@gmail.com Content-Type: text/plain; charset="us-ascii"

Have you checked your system clock? Try https://time.is which is very accurate. Some computer clocks can drift badly, and this can cause the need for constant tweaking, even with very stable satellites.

73,

Alan WA4SCA