Data transmissions?

[Blaise]

Hi all,

So I've been poking and prodding at GMRS to get up to speed.  I've made connections simplex with folks on the "travel channel", had a conversation over a repeater 40 miles away, learned to program my mobile and handheld units, and feel like I'm starting to get the hang of it (using a callsign is really alien and corny feeling if you've never done it before!).

So anyway, I set up one of my radios to scan continuously for a few days, and video'd the silly thing with my PC webcam so I could review later at high speed, all in an attempt to see what the local GMRS landscape looks and feels like.  But my scanning has revealed something unexpected.  Something/someone in my area is pumping a lot of what sounds like digital transmissions out on GMRS17/600, sometimes quick in bursts, sometimes for a couple of minutes at a time.

Now mind you, I'm no strict rule-follower, but I'm pretty sure the rules say you can't transmit data for more than a second at a time, so I feel like there's some sort of chicanery afoot.  If nothing else, I'm curious to see what they're up to!

Anyone have any thoughts about what's going on, or how to find out?

[tweiss3]

It's probably DMR. There are DMR pirates all over GMRS, and usually nothing you can do about it, as the FCC shrugs when you file a complaint. 

DMR has a beacon every 60 seconds, and the "minute" long version is a conversation. https://www.sigidwiki.com/wiki/Digital_Mobile_Radio_(DMR)

The only reason the one around here got taken down is someone knew where the tower was, and knew the tower owner. She did not like the idea of the liability and pulled the repeater instantly.

[Lscott]

On 12/22/2021 at 4:24 PM, tweiss3 said:

It's probably DMR. There are DMR pirates all over GMRS, and usually nothing you can do about it, as the FCC shrugs when you file a complaint. 

That’s a shame. CB radio turned in to the mess it is also due to FCC’s lack of interest in doing any meaningful enforcement actions. If we’re not careful GMRS could end in the same condition. 
 

The digital transmissions you heard may not be DMR. For example I have a number of commercial radios in my collection that can do DMR along with P25 phase 1 and NXDN all on UHF. Wait until a few people get together and use one of the other digital modes thinking they can have a “private” conversation because they have the radios to do it. And yes some of those radios have builtin encryption features too. If the FCC doesn’t step in there will be more of it.

Perhaps if there ends up being more and more pirate DMR operations maybe the FCC will given in and make it official. Either reserving some channels for digital voice or adding a few more to the pool specifically for digital. IMHO I don’t think it’s a bad thing to officially allow DMR on GMRS. I think it’s going to happens at some point. After dragging their feet for many years FM is now legal on CB along with the older AM and SSB modes. 

[wayoverthere]

54 minutes ago, Lscott said:

Perhaps if there ends up being more and more pirate DMR operations maybe the FCC will given in and make it official. Either reserving some channels for digital voice or adding a few more to the pool specifically for digital. IMHO I don’t think it’s a bad thing to officially allow DMR on GMRS. I think it’s going to happens at some point. After dragging their feet for many years FM is now legal on CB along with the older AM and SSB modes. 

a little pie in the sky, expecting logic from the gov, but IMO the best way to do it would be adding channels. if there's spectrum for it, how about 5 new digital channels, and 5 new repeater-designated channels, no sharing the outputs with simplex.  i suspect DMR would be the mode of choice; i don't see them leaving it open or tying to a proprietary standard. started having some success with DMR, but i'd have to say so far, P25 sounds better.

[gortex2]

To find out what it really is you can pick up a cheap SDR receiver and try to decode some of it. If its encrypted you wont be able to hear audio but the data should say if its DRM or what.

On the DMR topic the other issue is the CCR market. I had a guy hand me his radio when he couldn't talk to others on the jeep ride. It was a Baofeng DMR radio. After a few minutes realized he had all his channels set for digital. Many folks dont know how to program a radio so thats adding to the issue. I told him to throw out the radios and handed him a new set of motorola talkabouts. Worked great all weekend.

 

[DeoVindice]

There's an issue in this region with a commercial Capacity Plus DMR system splattering onto GMRS frequencies. The DMR system operator and FCC have been made aware of it but seem to have no interest in correcting the matter. You could be seeing something similar.

[Lscott]

7 hours ago, wayoverthere said:

a little pie in the sky, expecting logic from the gov, but IMO the best way to do it would be adding channels. if there's spectrum for it, how about 5 new digital channels, and 5 new repeater-designated channels, no sharing the outputs with simplex.  i suspect DMR would be the mode of choice; i don't see them leaving it open or tying to a proprietary standard. started having some success with DMR, but i'd have to say so far, P25 sounds better.

There is a slim chance of getting new channels. I think there is a better chance of one or two of the repeater channels being reserved for digital voice. It might be even better to reallocate the nearly useless low power narrow band channels 8 to 14  from 1/2 watt to 5 watts for digital voice use only.

While some might hate to hear this but the Chinese have jumped into the DMR market with affordable radios that with a firmware update could be made to adapt them to GMRS.

I haven’t seen any cheap affordable P25 radios from anybody yet, and likely won’t. The big boys supplying P25 radios charge top dollar because the target markets are public safety and other government agencies that have the big budgets. I don’t think they want their profitable P25 business ruined. They will petition the FCC to see that doesn’t happen.

[wayoverthere]

40 minutes ago, Lscott said:

There is a slim chance of getting new channels. I think there is a better chance of one or two of the repeater channels being reserved for digital voice. It might be even better to reallocate the nearly useless low power narrow band channels 8 to 14  from 1/2 watt to 5 watts for digital voice use only.

While some might hate to hear this but the Chinese have jumped into the DMR market with affordable radios that with a firmware update could be made to adapt them to GMRS.

I haven’t seen any cheap affordable P25 radios from anybody yet, and likely won’t. The big boys supplying P25 radios charge top dollar because the target markets are public safety and other government agencies that have the big budgets. I don’t think they want their profitable P25 business ruined. They will petition the FCC to see that doesn’t happen.

Yeah, I know the odds are slim. The overlap between current radios in the wild and the new if they reallocated the existing channels though...would make some sense with the narrow bandwidth dmr uses though.

Yeah, I've always wondered why p25 is generally so expensive. I was floored when I found a "p25 capable" icom for a pretty reasonable price, but to buy the p25 upgrade was over $300 (for basically just a license).

[Lscott]

13 hours ago, wayoverthere said:

Yeah, I know the odds are slim. The overlap between current radios in the wild and the new if they reallocated the existing channels though...would make some sense with the narrow bandwidth dmr uses though.

Yeah, I've always wondered why p25 is generally so expensive. I was floored when I found a "p25 capable" icom for a pretty reasonable price, but to buy the p25 upgrade was over $300 (for basically just a license).

P25 was marketed to public safety and government agencies to facilitate interoperability. Because of the target market there is little incentive for manufacturers to offer cheaper radios. At least until the Chinese decide to jump in. At that point don’t be surprised that companies like Motorola will do everything they can to lock them out, including putting special “tweaks”, additions to the standard protocol, to only work with their equipment to use the new unique features.

I did manage to get a good deal on a very clean, like new condition, Kenwood TK-5320 radio a while back for $110 more or less. Haven’t seen a deal that good before or since. The one I got was the Type-2 Phase-1, perfect for Ham use. I would like to find a similar deal on a TK-5220. That’s likely to take a long time checking the auction site to jump on it when I spot one.

https://pdfs.kenwoodproducts.com/18/TK-5220&5320Brochure.pdf

[wayoverthere]

58 minutes ago, Lscott said:

P25 was marketed to public safety and government agencies to facilitate interoperability. Because of the target market there is little incentive for manufacturers to offer cheaper radios. At least until the Chinese decide to jump in. At that point don’t be surprised that companies like Motorola will do everything they can to lock them out, including putting special “tweaks”, additions to the standard protocol, to only work with their equipment to use the new unique features.

I did manage to get a good deal on a very clean, like new condition, Kenwood TK-5320 radio a while back for $110 more or less. Haven’t seen a deal that good before or since. The one I got was the Type-2 Phase-1, perfect for Ham use. I would like to find a similar deal on a TK-5220. That’s likely to take a long time checking the auction site to jump on it when I spot one.

https://pdfs.kenwoodproducts.com/18/TK-5220&5320Brochure.pdf

yeah, i can't say i got as good a deal on either of my P25 handhelds (vhf vx-p829, and uhf vx-p824), but they're in good shape. 

grabbing a mobile seriously tempts me, but if i'm realistic, there isn't THAT much around either....DMR has more repeaters than P25, C4FM/Fusion, and D-Star combined.  maybe it's just my searches, but it seems like UHF outweighs VHF a bit in P25, probably 60/40, with both giving way to 700/800.

[Lscott]

1 hour ago, wayoverthere said:

yeah, i can't say i got as good a deal on either of my P25 handhelds (vhf vx-p829, and uhf vx-p824), but they're in good shape. 

grabbing a mobile seriously tempts me, but if i'm realistic, there isn't THAT much around either....DMR has more repeaters than P25, C4FM/Fusion, and D-Star combined.  maybe it's just my searches, but it seems like UHF outweighs VHF a bit in P25, probably 60/40, with both giving way to 700/800.

Same by me. Very little P25 traffic. Same for NXDN too. I wanted the VHF version for my radio collection. There appears to be a VHF repeater in the area.

Yeah, most of the digital voice modes seems to be on UHF most likely because there is a lot more spectrum available. With 30MHz on the 70cm band to play with it isn’t too hard to find a spot to operate without annoying other operators.

If I had to pick one mode it would be DMR over the others. There are some technical reasons I would prefer it. One can operate a SFR, single frequency repeater, so no expensive cavity filters required. The other is due to the TDMA, time division multiple access. You can run full power on TX but the average power is about half what you need for typical FM signals so battery life is much longer on portable radios.

[n4gix]

The doubling of voice communications on a single frequency is also a major plus!

[tcp2525]

Let's keep digital out of GMRS!! There's no need to make things more complicated so that people can ask for radio checks or kerchunk all day. Just look at the sh!t show we have on the amateur bands with DMR. I'm sticking to analog.

[wayoverthere]

definitely more efficient use of the spectrum. maybe it's just my setup, or setups on the other end, but everything i've heard so far on DMR, people sound very...robotic, while p25 has sounded about as natural as analog.

40 minutes ago, tcp2525 said:

Let's keep digital out of GMRS!! There's no need to make things more complicated so that people can ask for radio checks or kerchunk all day. Just look at the sh!t show we have on the amateur bands with DMR. I'm sticking to analog.

if they set a couple of digital only channels, and the manufacturers were able to boil it down to the same level of menu as some of the current bubble packs, i can't see why it would be any worse than it is now....instead of ctcss or dcs, match channel and color code, and go.  they already have the programming able to handle the switch between wideband on some channels and narrow on others, out of the box.  perhaps i haven't played with DMR enough (especially simplex) to really see the potential issues, though.

[Lscott]

It’s not really that hard. All you need to pick is Slot 1 or Slot 2, Color Code and talkgroup.

https://www.raqi.ca/~ve2rae/dmr/Amateur_Radio_Guide_to_DMR.pdf