With the Motorola Oncore software I am using, I have found the reported time to exactly match WWV. I assume that the software takes leap seconds into account, though I have not checked the documentation. A friend who works at Motorola did the initial set-up
-----Original Message-----
From: Ray McKnight [email protected] Sent: Aug 25, 2006 1:16 AM To: George Henry [email protected] Subject: Re: [amsat-bb] Re: Accuracy?
You are aware that GPS time and "earth" time are two different critters? The GPS constellation is not adjusted for leap seconds, so the time your GPS receiver displays is something like 13-14 seconds off actual earth time.
Could make for some big problems trying to track a highly eliptical orbit or even LEO with that much error.
----- Original Message ----- From: "George Henry" [email protected] To: "amsat bb" [email protected] Sent: Thursday, August 24, 2006 21:27 Subject: [amsat-bb] Re: Accuracy?
It depends on the level of automation of your station... if you are using fixed antennas, you only need enough accuracy to know when the satellite
is
in view. If you are using rotor control, it depends on the beamwidth of your antennas ( the narrower the beamwidth, the more critical the aiming becomes). If you are using doppler control, then very high accuracy is needed: a few seconds of error can translate to several hundred hertz of doppler shift on a high pass.
I have my XP machines set to check an internet NTP server every 4 hours. For Field Day, I use a GPS receiver to keep the PC clock dead on, and
always
use GPS to set my station coordinates accurately when portable. And when
in
doubt, I update my keps right before operating, and at least once a week otherwise.
George, KA3HSW