[amsat-bb] Re: Listening on USB when operating CW
Peter.Ng at bccdc.ca
Fri Feb 7 13:09:05 PST 2014
Thanks Clayton, that's good to know....
73 Peter ve7ngp
That is correct and what I have attempted to describe. A station not adjusting properly for Doppler shift will appear to "move" across the passband into stations who are making corrections. (voice or CW)
There are several categories for correction, as I see it by order of occurrence...(and there may be more)
1 - People who use "full" Doppler correction via software, adjusting both TX and RX to stay on the satellite's frequency.
2 - People who use "half" Doppler correction by tuning the higher of two frequencies. This is common for people who are portable or want the simplest method of staying on another station. In the mode, you will move slightly. I do this often in the field. It's not perfect.
3 - People who use "TX only" correction. I see this often and I believe it's an incorrect practice to always tune TX because sometimes that means on mode J you'll likely move across QSO's in progress.
4 - Probably the least common I observe, people who use "full" Doppler correction manually. I believe it is a little more difficult to do this on fast moving LEO's, especially on CW.
My original email was trying to discover whether or not listening on USB while transmitting on CW might make it easier for "CW drifters" to know they are part of a problem. Occasionally when this problem occurs with USB voice, the perpetrating stations are not able to hear well enough to know they are causing a problem.
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