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Smartnet & cqpsk vs fsk4 #200
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The proper voice channel setup for Smartnet can be found in
smartnet_example.json.
Specifically the following parameters:
demod_type="fsk4"
filter_type="widepulse"
If that's not getting you good digital audio, try changing
filter_type="rc" and see if that helps.
I'm actually a little surprised that demod_type="cqpsk" works at all for
digital audio since it is supposed to follow the P25 Phase 1 specs which
mandate C4FM/FSK4 encoding. The problem is, I've never seen an actual
Motorola spec, just TIA-102 standards docs.
Let me know whether changing widepulse makes any difference.
Graham
…On 1/19/24 17:12, Richard Fuchs wrote:
Hi,
Is there a reason why the smartnet NB FM demodulator is only enabled
for fsk4 channels but not for cqpsk channels? See
https://github.com/boatbod/op25/blob/master/op25/gr-op25_repeater/apps/p25_demodulator_dev.py#L531
I'm listening to https://www.radioreference.com/db/sid/861 and with
fsk4 I get distorted digital audio but good FM, and with cqpsk I get
good digital audio but no FM. Patching up that line to also allow
cqpsk makes things work.
Is this an oversight or have I configured something wrong?
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Yeah I tried with the default settings (fsk4/widepulse) first and that gave me very choppy audio. For some reason changing to cqpsk made it work. BUT fsk4/rc also seems to work perfectly. Solved, thanks! |
Do you know if your Smartnet system is simulcast? Widepulse (for simulcast) increases the filter bandwidth vs the rc filter used by standard P25. GrahamOn Jan 21, 2024 1:13 PM, Richard Fuchs ***@***.***> wrote:
Yeah I tried with the default settings (fsk4/widepulse) first and that gave me very choppy audio. For some reason changing to cqpsk made it work. BUT fsk4/rc also seems to work perfectly. Solved, thanks!
—Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>
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No idea. Is there a way I can tell? Otherwise I only know what's listed on RR. |
Hi,
Is there a reason why the smartnet NB FM demodulator is only enabled for fsk4 channels but not for cqpsk channels? See https://github.com/boatbod/op25/blob/master/op25/gr-op25_repeater/apps/p25_demodulator_dev.py#L531
I'm listening to https://www.radioreference.com/db/sid/861 and with fsk4 I get distorted digital audio but good FM, and with cqpsk I get good digital audio but no FM. Patching up that line to also allow cqpsk makes things work.
Is this an oversight or have I configured something wrong?
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