OpenGD77

Thanks. I've been waiting for in-call GPS for a long time. Is there a possibility to leave TA/APRS settings in Options menu (or elsewhere) as a default setting when per-channel TA/APRS is not defined? I.e. I'd like to explicitly disable TA for one channel/timeslot and enable by default for other cha...

1. Adding a GPS receiver to a DM1801 won't work, because the OpenGD77 on the GD77/DM1801/RD5R does not have support for GPS, there is vitually no free space in ROM to add this. It's not a problem anymore, now I have RT-3s ;) 3. Its not practical to support modified hardware. 4. No CPU does not supp...

We have no control of how long it takes for the GPS to get a fix. I posted to a separate topic about how very slow the GPS is in these radios are I am working on DMR Tx of position in the TA data, as there seems to be a standard for this, and the firmware already decodes the location in the TA data...

ATGM-336H is GPS/BDS-capable, so parsing these messages should be enough. Also $xxGSA and $xxVTG messages may be of some interest. If somebody decides to replace the module with a different one of the same form-factor - then it may not display SVs correctly. However, xxRMC will be more or less the s...

Probably GNSS module firmware is different. I even have an older module based on the same AT6558 chip which does not support BDS at all. AFAIR there was an update to NMEA protocol. Now it sends $GNGGA, $GNRMC etc. for multi-GNSS modules. The SVs are the same, as per GNSS: $GPGSV, $GLGSV, $GAGSV and ...

VK3KYY wrote: ↑

Wed Nov 02, 2022 11:09 pm

BTW.

u-centre does not seem to support decoding of Chinese satellite data.

Tools -> Preferences -> Generic -> NMEA Custom BDS Talker ID
Set it to BD
(IIRC it's empty by default).

Some GNSS modules, including u-blox, report BeiDou as i.e. $GBGSV. Some others - as $BDGSV, which is the case.

How about not to disable NMEA output on UART RX completely - but to suppress it for a few seconds? It should be sufficient for CPS to establish a communication. Also, does CPS use some kind of handshake now? I.e. the radio waits not just any UART output from PC - but a predefined byte sequence. And ...

Thanks. Just received RT-3s today to play with - and here we have another alpha ;) However, there are two things I'd like to mention: 1. It looks like in NMEA mode radio sends only <LF> at the end of each line, not <CR><LF> as per NMEA-0183 standard. 2. I have no issues reading NMEA messages in putt...

Tested DMR reception at 439MHz a couple years ago. Baofeng RD-5r: signal loss at about -124dBm. Unfortunately I had no DM-1801 or GD-77 then. TYT MD-UV390: signal loss at -122dBm - and the radio is very picky about 4FSK levels, at least with it's stock firmware. I.e., when due to hardware bug MMDVM_...

VK3KYY wrote: ↑

Sun Sep 25, 2022 9:21 pm

Unless someone cracks the firmware encryption, it would never be possible to put any firmware on this radio.

Don't know if it's the thing - but please check https://github.com/OK2MOP/MD1702-tools
Looks like it can read/write firmware - or at least that's what author said in the description.