Its more about saving TX power than anything else. If anything opens the squelch on an FM transponder, it is FULL TX power from the satellite even if almost nothing is there.
On a linear bird, the oTX power is proportional to the input. so the spacecraft power is not wasted on wek signals.
Bob WB4APR
On Sat, Feb 3, 2018 at 10:45 AM, Philip Jenkins n4hf.philip@gmail.com wrote:
I understand why FM satellites need an PL tone on uplink (to keep out land-mobile services, like taxi-cabs, etc), but why is a PL not required for the linear sats utilizing the same frequencies? A linear transponder is certainly capable of receiving/transmitting an FM signal (albeit not successfully demodulating that signal).
This question came up at a satellite presentation I did, and I had never thought about it. ( Moreover, will radios even transmit a PL on SSB/CW transmissions?)
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