doplar shift on uplink - Satellites Forum at eHam.net

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eHam.net Forum : Satellites : doplar shift on uplink

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doplar shift on uplink	Reply
by KC9ERZ on August 30, 2009	Mail this to a friend!
I am fairly new to working the FM LEO Sats. I have no problem getting into AO51 with a fixed uplink freq of 145.920. But on AO27 and SO50 I have a hard time. Do I need to compensate for doplar shift on the uplink to AO27 and SO50? Also I know that SO50 requires a PL tone of 67. What kind of tone is this? Thanks, Greg KC9ERZ

RE: doplar shift on uplink	Reply
by KO4MA on August 31, 2009	Mail this to a friend!
There isn't any need to tune for doppler on the 2m uplink on any of the FM satellites. The PL tone on SO-50 is the same type of tone as used for regular terrestrial repeaters, also called CTCSS. On SO-50 it's used to key the transmitter on and off. Also, remember AO-27 is only on for part of the afternoon passes. Just wanted to be sure you knew that ;-) If you are using a handheld antenna like an Arrow, try twisting it to change the polarity while uplinking. This can make a big difference depending on the satellite orientation since the receive antenna on the satellite is a linearly polarized whip. 73, Drew KO4MA

RE: doppler shift on uplink	Reply
by KC9ERZ on August 31, 2009	Mail this to a friend!
Thanks for the info on the uplink....and sorry for the typo (should have typed doppler, not doplar)! Greg

RE: doppler shift on uplink	Reply
by KB9CRY on September 1, 2009	Mail this to a friend!
Normally you leave transmit frequency alone and vary your receive frequency for doppler.

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