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No RX/TX

Posted: Sun Feb 18, 2024 3:44 pm
by k9amt
Moved a Dual hat MMDVM to a pi3b. Flashed Pistar 4.20.1 Flashed modem to 1.6

Using for P25. Pistar shows green and the dashboard displays gateway activity from connected host.

Detected modem is:

Detected MMDVM_HS Port: /dev/ttyAMA0 (GPIO) Baud: 115200 Protocol: V1
Modem Data: MMDVM_HS_Dual_Hat-v1.6.1 20230526 14.7456MHz dual ADF7021 FW by
CA6JAU GitID #7ff74edFF36066E3937554157013460

MMDVM does give a good BER% with a +800 offset

475 offset is stated on the label.

Modem does TX CW ID and on frequency as verified by my service monitor.

Modem does not RX in normal operation other than every 10 minute CW ID otherwise NO LOCAL TX OR RX of any kind. Network traffic does get transmitted.

What am I doing wrong?

Re: No RX/TX

Posted: Sun Feb 18, 2024 4:43 pm
by MW0MWZ
Ignore what the label says, I've found on my own boards that the required TX/RX offset can change with the newer 1.6.1 firmware.
You will certainly need to tune it.

Re: No RX/TX

Posted: Sun Feb 18, 2024 5:36 pm
by k9amt
I'll try another tuning cycle. Modem responds in mmdvcal but not in normal operation.

Re: No RX/TX

Posted: Sun Feb 18, 2024 5:55 pm
by k9amt
Recalculate +800 offset. Still no local RF activity response from the modem. :|

Re: No RX/TX

Posted: Mon Feb 19, 2024 12:21 am
by k9amt
Operational BER is horrible 5 to 8% on local RF and doesn't match what is achieved in MMDVMcal which is under 1%. Local activity TX also locks up and requires a hard reboot of the system.

Re: No RX/TX

Posted: Mon Feb 19, 2024 1:19 am
by MW0MWZ
how large is the frequency split ? on duplex boards I'd suggest 9+ MHz split