GD-77 promiscuous again?

New users must post here first and let us know a little bit about yourself.
Post Reply
K5GT
Posts: 4
Joined: Sat Dec 25, 2021 4:38 am

GD-77 promiscuous again?

Post by K5GT » Mon Dec 27, 2021 1:22 am

Sorry if it has been asked before.. but guess that's why I ask it in this group.
I have a 'local' repeater programmed with some Talk Groups that I found on the Brandmeister website. For the South Texas TG I know I am able to hit the repeater as I can also see my self in the Last Heard list of the repeater.
Now that I have the radio up and running I see activity on the radio (Green LED and a 50% signal), But I don't hear a thing. The repeater is using CC 2 so no need to filter that out.
But how can I find out what the activity is on the repeater. I did turn the filter on on the TS (inversed display) and DMR filter to none.
Is there somewhere a good description to just be able to listen to anything or do I have another problem?

Thanks,

John

ok1pt
Posts: 167
Joined: Mon Jul 20, 2020 3:38 am

Re: GD-77 promiscuous again?

Post by ok1pt » Mon Dec 27, 2021 5:20 am

K5GT wrote:
Mon Dec 27, 2021 1:22 am
Sorry if it has been asked before.. but guess that's why I ask it in this group.
I have a 'local' repeater programmed with some Talk Groups that I found on the Brandmeister website. For the South Texas TG I know I am able to hit the repeater as I can also see my self in the Last Heard list of the repeater.
Now that I have the radio up and running I see activity on the radio (Green LED and a 50% signal), But I don't hear a thing. The repeater is using CC 2 so no need to filter that out.
But how can I find out what the activity is on the repeater. I did turn the filter on on the TS (inversed display) and DMR filter to none.
Is there somewhere a good description to just be able to listen to anything or do I have another problem?

Thanks,

John
Hi John!
Are you sure, that the repeater is a single-mode DMR only ?
It may be either a mixed FM/Digital repeater or possibly multi-mode digital repeater for example for D-star, DMR, C4FM, P25 etc. And your radio will play just the FM or DMR signal (according to its setting) and nothing more.
If you see your radio with green LED on but not playing, try to monitor the channel in analog. Either you'll hear somebody speaking, or you will hear a digital noise. It's relatively easy to distinguish DMR from other digital modes, because DMR only has a framed data structure, so you can hear a "rhytm" in the signal, while the others are just sending plain noise without any significant pattern (I never listened to P25 so I don't know how does it sound, but neither D-star nor C4FM have any recognizable pattern).
Or just inform yourself from some of your neighbor hams having more experiences with the repeater...
With regards / 73,
Pavel

VK3KYY
Posts: 7473
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: GD-77 promiscuous again?

Post by VK3KYY » Mon Dec 27, 2021 8:26 pm

I agree with Pavel. Try listening on analogous. Hold button SK2 in, and the radio will go into monitor mode and switch to FM and open the squelch

DMR does sound different from the other modes because of the 30ms Timeslots, but unless you can compare the sound with another DMR repeater it may be difficult to tell if it is DMR.

Also the published CC may be wrong, so you could try temporarily disable the CC filter and force the radio to scan for the correct CC when it receives a signal, but you should not leave CC filter permanently disabled because the scan / lock time for the hardware to ring the CC is several seconds at the start of each received over.

User avatar
F1RMB
Posts: 2517
Joined: Sat Nov 16, 2019 5:42 am
Location: Grenoble, France

Re: GD-77 promiscuous again?

Post by F1RMB » Mon Dec 27, 2021 8:38 pm

Hi,

Some audio samples:
https://www.sigidwiki.com/wiki/Digital_ ... adio_(DMR)


Cheers.
---
Daniel

Post Reply