Unusual P25 Behiviors

Help with P25 issues
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ke8owx
Posts: 7
Joined: Fri Jan 01, 2021 7:02 pm

Unusual P25 Behiviors

Post by ke8owx »

I'm new to P25, but this doesn't seem normal compared to other supported digital modes.

I have a P25 HT, and it is programmed appropriately with the repeater/hotspot and the correct C4FM Astro personality.

I have a hotspot, and access to a multi-mode repeater based on the STM32 hardware and pistar software. On both, I have experienced similar conditions and problems over the past week:
1) Even when not in use, the first call takes multiple tries to get in.
2) BER is all over the place, from perfect to not great, even with a strong signal (-43dbm)
3) There is often ridiculous packet loss coming back into pistar (80%+), even with excellent internet connections (hardwired 400Mbps)
4) Often I notice it can take up to 3 seconds for pistar to accept the call
5) none of these happen with DMR, D-Star or YSF on the same hardware

I have attached dashboard screenshots from both the repeater and my hotspot. Am I missing a setting, or is this normal P25?

EDIT: uploads won't work, so the screenshots are at the attached link: https://1drv.ms/u/s!AmNCKj05x9hYgtgcXtR ... g?e=mxgdF5
ke8owx
Posts: 7
Joined: Fri Jan 01, 2021 7:02 pm

Re: Unusual P25 Behiviors

Post by ke8owx »

Frequency & stability are something I need to look into. I know I don't have the equipment necessary to check that, but I'll reach out to some friends that might.

I can understand the scanning of modes, but the massive delay doesn't happen with other modes, and the repeater has every mode enabled.
ke8owx
Posts: 7
Joined: Fri Jan 01, 2021 7:02 pm

Re: Unusual P25 Behiviors

Post by ke8owx »

I've exhausted the tools I have available. Utilizing a dummy load and a power meter/frequency counter (uncalibrated) I determined output power is expected on both high and low, and frequency is stable to 1kHz (the accuracy of my equipment). I can't tell if it's exactly on frequency, because its not calibrated. I also used the dummy load and my TinySA, and the P25 matches the wave form from everything I see about calibrating P25 equipment. Obviously its not a true alignment or measurement, but it does show that I either need to find someone to stick it on good equipment for an alignment or deal with it.
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