OpenGD77

Hi,

For a couple of days the hotspot was working great with my radio. One day all of a sudden it would not listen to my hotspot. Folks can hear me when I press the PTT on BM network, I can see the hotspot working as it should on the dashboard, frequencies are matching Rx and Tx, color code, Timeslot.

For a minute I thought that the mmdvm hat was not transmitting to my HT so I bought a second one, just to find out that it didn't work either so I am convinced it is my radio. No issues on analogue simplex or local repeaters.

It works just fine when using a local DMR repeater (NCPRN).

Any hints or clues to fix it would be much appreciated.

Someone else recently had a similar problem. That turned out to be that the tx level setting on the hotspot was too low. That effectively sets the deviation of the hotspot modulation, which is quite critical for DMR.

G4EML wrote: ↑

Sun Apr 09, 2023 11:51 pm

Someone else recently had a similar problem. That turned out to be that the tx level setting on the hotspot was too low. That effectively sets the deviation of the hotspot modulation, which is quite critical for DMR.

The default on this hotspot is 50 so I guess that is 50%. I will up this number and see if anything changes.

Thank you

I changed the TX level to 100 on the overall setting as well as the DMRtx and I can see the signal bar on my HT all the way up so the signa is there but I don't hear a thing.

I know this will sound nutty, but I ran into this problem with 5 different NanoPi hot spots.

I found that hinged antennas can be a problem. Try removing it and see if you hear audio. If you do, replace the antenna with a shorty antenna sans hinge.

My guess is that these antennas are 2.4GHz being sold as 433 MHz antennas and the SWR is too high and RF is getting back into the hat.

I discovered this solution by accident. If you don't have a hinged antenna, you can still try the same procedure. Good luck

73, Dick,WN3R

I had this issue recently, with both my MD-UV380 and DM-9HX... My Anytone D878UV was fine however.

Setting "DMRTXLevel" to 60-65, seems to have solved the issue (latest version of Pi-Star on an RPi3 with MMDVM_HS_Dual_Hat).

Having said that, I've installed W0CHP-PiStar-Dash (a more up to date fork of Pi-Star) last week, without the need of changing DMRTXLevel, it worked straight out of the box. On the same Hotspot hardware as previously.

wn3r wrote: ↑

Thu Apr 13, 2023 12:55 pm

I know this will sound nutty, but I ran into this problem with 5 different NanoPi hot spots.

I found that hinged antennas can be a problem. Try removing it and see if you hear audio. If you do, replace the antenna with a shorty antenna sans hinge.

My guess is that these antennas are 2.4GHz being sold as 433 MHz antennas and the SWR is too high and RF is getting back into the hat.

I discovered this solution by accident. If you don't have a hinged antenna, you can still try the same procedure. Good luck

73, Dick,WN3R

Bingo!!!!

I took of the antenna, took the HT placed it against the antenna port and I heard the DMR signal

This was puzzling me for the longest time and now I know what is wrong. I will buy some 440 antennas that will fit the hotspots and try it again.

Thank you for the pointer!

Instead of that bad hinged/folded antenna you could use a real 70cm antenna with a 90 degree SMA-SMA adapter.