MMDVM hotspot ,TX problem

General support for the Pi-Star System
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Posts: 2
Joined: Mon Apr 18, 2022 7:36 pm

MMDVM hotspot ,TX problem

Post by ap2mhc »

i have an mmdvm hotspot that is connected to tg 91, I can receive it on my ailunce HD1 but i cant transmit on it, if immediately press ptt after receiving any call , then i am able to transmit to hotspot and it shows in the dashboard,other wise if the talkgroup is silent i can't transmit on it,

i am unable to address the issue.

Help needed
Posts: 731
Joined: Fri Jul 20, 2018 1:15 am

Re: MMDVM hotspot ,TX problem

Post by AF6VN »

Are you sure the radio is configured on a channel for talk-group 91? Depending upon configuration your "working" replies might be going as private replies to whatever DMR ID came in to it.

Second, what setting(s) does the channel have for color-code? It may be that you have some setting that only allows transmitting when the color-code is an exact match (though I've not seen this condition with my TYT units... "Admit Criteria: Color Code", "In-call Criteria: Always"). I've never really found clear documentation on what those options really control (Admit has always/channel free/color code). My Anytone D878xxxx has "TX Permit" with always/channel free/Different Color Code/Same Color Code -- I have it set for "different". According to the hint text in the editor:
  • Always -- radio will transmit at any time
  • Channel Free -- radio will transmit only if there is no other traffic on the channel
  • Different CC -- radio will transmit on a busy channel IFF the color code is a mismatch
  • Same CC -- radio will transmit only if a received signal on the channel matches the configured color code
There is no explanation as to what happens if one has one of the CC options selected, and there is no recently received traffic (I'm presuming "no recent CC" qualifies as "different", but a strict interpretation of "same" could mean the radio can only reply during the interval when the received contact is still active on screen).

A third factor -- may not apply (I run D-STAR and DMR on the same unit) It sometimes takes me two or three PTT cycles (of a few seconds each) when the Hotspot is in "Listening" (vs "Listening DMR") for the decode to figure out what mode the inbound RF is using.

Dennis L Bieber
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