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QRM 2m, question for sat builders



Seems to me the QRM issue should be taken to heart by all those planning or building LEOs for 2m and 70cm. At risk of beating a deceased equine, Mode J is a pain compared to Mode B. Downlinks are hard to hear on Mode J compared to Mode B. The biggest new user problem I hear about is not hearing the satellite. This has never really been an issue with 2m downlinks. DO-17, SO-35, RS-12/13, AO-7 and I'm sure others were easy to copy on simple omni antennas. The 435 downlinks for the most part are not so easy. QRM is very much less prevalent on 435, and if it is there it quickly is dopplered away from a single uplink frequency.

I have a question for those "in the know" (this means I'm not interested in speculation). Why are so many of the newer LEOs designed as Mode J? Is it due to the commercialization of the Microsat design? More commercial downlinks available in the UHF range? Harmonic suppression at the satellite end? I truly wonder what the impetus towards J is....

Don't get me wrong...I love all the ham satellites. I just would love to see more easy to hear downlinks, and less newbie heads beating against the wall trying to hear a satellite downlink.

73, Drew KO4MA
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