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Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 2:22 pm
by EA7KLK
Hello,
I have been testing using a Retevis RT84 as the Radio for a Pi-Star Hotspot for some days now. Fact is, both on TGs and when testing with PC to 9990 (Parrot) my voice quality is very bad. BER in the RF dashboard is 0, max 2-5% when I go out of the house. Ferrite on both ends (Raspberry Pi and radio) of the USB cable.
My (external) antenna (homebrew GP) is well tuned and resonant, SWR 1:1,15 at the operating frequency of the hotspot.
Any idea what else I could check?
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 2:25 pm
by F1RMB
Double check that TXOffset and RXOffset are set to 0 in you MMDVMHost ini file (/etc/mmdvhost on your pistar, or using the expert editor in the web interface).
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 2:56 pm
by EA7KLK
F1RMB wrote: ↑Sun Jan 21, 2024 2:25 pm
Double check that TXOffset and RXOffset are set to 0 in you MMDVMHost ini file (/etc/mmdvhost on your pistar, or using the expert editor in the web interface).
Yep, Offset is 0. That's not it, it seems. Frequencies on the hotspot walkie and on the one I use to talk are also OK. It's also not the talkie, works fine with the other low-powered hotspot I have. Both, the one connected to Pi-Star as well, tried and tested.
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 3:28 pm
by EA7KLK
By the way, it sounds crap with the original antenna as well. I'm gonna reset the radio to default, maybe I have fat-fingered something...
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 3:40 pm
by EA7KLK
Reporting back: Radio reset was unsuccessful in terms of audio quality. Could it be that WSPD Pi-Star fork is causing trouble? Has anyone experienced this?
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 3:49 pm
by F1RMB
How's your power setting set on your two transceivers ?
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 6:01 pm
by EA7KLK
F1RMB wrote: ↑Sun Jan 21, 2024 3:49 pm
How's your power setting set on your two transceivers ?
1W. Next try, swap out the radios. I'll report what happens.
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 6:41 pm
by EA7KLK
OK, I tried again in DMR Direct mode from one radio to another. The RT84 is clearly putting out RF but no audio when using the built-in microphone.
Strange enough, when I connect an external headset to it, it transmits fine and with appropriate quality
I reflashed OpenGD77 (hoping that this might fix it, but no luck)
Any ideas - I'm not scared of opening devices for fun and profit, have magnifying glasses and have known for a long time which end to hold a soldering iron.
Else, as I am really fond of the hotspot functionality with an external radio - I dare not connecting a MMDVM radio board too a proper antenna, lest I pollute the entire RF-spectrum in my area.
Any suggestions to replace the RT84? Cheapest-ass OpenGD77 compatible radio that's not unobtainium.
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 7:28 pm
by VK3KYY
EA7KLK wrote: ↑Sun Jan 21, 2024 6:41 pm
OK, I tried again in DMR Direct mode from one radio to another. The RT84 is clearly putting out RF but no audio when using the built-in microphone.
Strange enough, when I connect an external headset to it, it transmits fine and with appropriate quality
I reflashed OpenGD77 (hoping that this might fix it, but no luck)
Any ideas - I'm not scared of opening devices for fun and profit, have magnifying glasses and have known for a long time which end to hold a soldering iron.
Else, as I am really fond of the hotspot functionality with an external radio - I dare not connecting a MMDVM radio board too a proper antenna, lest I pollute the entire RF-spectrum in my area.
Any suggestions to replace the RT84? Cheapest-ass OpenGD77 compatible radio that's not unobtainium.
RT-84 is a rebranded Baofeng DM-1701
Re: Some hotspot woes... Bad intelligibility
Posted: Sun Jan 21, 2024 8:32 pm
by EA7KLK
Could there be an issue in MMDVM or Pi-Star? Any news from other users of this mode? I mean, all was fine until Wednesday or so. JSWT updated often, but I also tried a Pistar image with identical results.
Well, there is a small change... Pistar gives me a BER of between 8-12%. I guess this is quite high. On my dual hotspot I don't remember ever seeing more than 2-3%. Loss is 0%, however.
I have DMR CRC on on both radios. Could that be a reason?
This is driving me a tad nuts.