I'd expect most ham stuff will produce lots of IPM when worked hard. The IPM might be your limit on the IC7200 Has anyone measured the IPM ?
oh that's INCIDENTAL PHASE MODULATION. there is usually an (unwanted) relationship with amplifiers between amplitude and phase. IE crosstalk from AM >> PM. glen . On 26/07/2015 7:49 AM, David Rowe wrote: > Hi Michael, > > FB on getting your SM1000 up on the air - lets have a QSO some time! > > Adjusting so your ALC just moves, and 20-25 watts average power for a > 100W PEP rig is a useful rule of thumb for FreeDV 1600. The classic > "rookie mistake" is overdriving the SSB tx, which causes clipping and a > poor bit error rate at the receiver. Make sure any speech compression > is off too. > > The best way to adjust your tx drive is monitor the SNR of the signal > using a 2nd rx and the FreeDV GUI program. For example when I tx with > my IC7200, I have a FT817 nearby with no antenna and the RF gain wound > down. I feed the rx audio into my laptop and monitor the scatter > diagram and SNR. Incidentally, with my IC7200 I can't seem to get > better than 20dB, perhaps due to it's sharp tx filtering. > > I have a video that demonstrates this (and explains scatter plots): > > http://www.rowetel.com/blog/?p=3109 > ------------------------------------------------------------------------------ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
