Thanks Markus for the detailed info about your observations.
Giving that both ZDF and 3sat are available here only via a satellite
link, I think that
the GPS 1pps way is still the better to follow. I just wanted to avoid
to install a fixed
GPS antenna on my roof, but it looks like I will have to.
73 Alberto I2PHD
[email protected] wrote:
Hi Alberto and LF group,
the Astra downlink I observed was analog FM (10964MHz horizontal). The
satellite signal was an exact, but delayed replica, with apparently no
buffering. The only problem is that the path delay has some daily
Doppler variation due to the small excentricity and inclination of the
not-quite geostationary orbit. During my comparisons in November 2001,
this shift amounted up to about 50µs peak-peak over 24h. Furthermore,
the time-shift is not easily predictable, as tidal effects and
occasional correction maneuvers cause a day-to-day variation in the
orbital parameters. - If you can receive terrestrial ZDF, one very
crude but enlightening experiment is to simply combine the two video
sources via different resistors and watch the weaker signal's sync-bar
wander across the screen in the course of a day.
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