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Lime SDR Mini carrier in RX mode?

Posted: Tue Jan 29, 2019 4:31 pm
by g8vpg
I have been playing with my Lime SDR Mini this afternoon using the latest DATV Express software. I've noticed that with TX turned off, it outputs an unmodulated carrier about 20dB down on the ATV signal. Has anyone else noticed this?
It is giving superb pictures at 100ks/s, DVB-S2, 8psk, H265, a bit laggy but incredible video quality for 120KHz bandwidth. I can't get Minitioune to lock below 100ks/s, it tries but doesn't quite get there. This should be good for minimising the satellite uplink power requirement.

Re: Lime SDR Mini carrier in RX mode?

Posted: Wed Jan 30, 2019 9:04 am
by g0mjw
It does that. It also does undesirable things when it calibrates. You need to gate the output via some sort of PTT, e.g. a relay to avoid radiating/interfering and ideally shut down any amplifiers following the Lime. I think the Pluto does it too.