DMR on FRS/GMRS (seemingly Voice Inversion, not DMR)

[LegitByDefault]

That's not a question.

 

People in my area are using DMR - out of CCRs no less - and their emissions are spattered all across the band... From channel 1 through to 22. This is a daily, continuous problem.

 

What say ye?

 

I don't use DMR so I'm not certain that's the case, or if it's some form of scrambler/encryption, but I'm unable to decrypt it, and there's no CTCSS/DCS tone which the Moni key would have bypassed. A friend said it might be DMR. By continuous, I don't mean unrelenting... The breaks between their transmissions are clear static and much louder than their transmissions because my volume is up. They're not on a timed schedule. The voices change tone - clearly different people communicating. This isn't environmental or other machine interference.

Edited January 16 by WSKK463
Additional information + title adjustment to reflect current perception

[nokones]

Maybe it is skip skipping off the ice from Canada or Russia or even Greenland.  Greenland has a lot to talk about these days and probably would like to keep their traffic from prying ears.

[LegitByDefault]

Lol @ Greenland

It sounds like I'm trying to tune a AM/FM radio by rotating the dial too fast. I noticed their signal is strongest on channel 3.

 

That is to say, if they're using DMR on a Baofeng, on FRS/GMRS, centered on channel 3, and I can hear them all the way up to 462.72500... their transmissions are being received well below the FRS/GMRS band, through business/commercial, and interfering with numerous bands, which I believe includes public safety, state maintenance, etc.

[WRZK526]

We have one at 462.537 which interferes with my reception of a repeater at 462.550. I am not sure of the source but we are trying to track it down. Sounds like a digital signal probably DMR. If we locate we will try confrontation and if that doesn't work try FCC which I understand is a long shot. I know someone with a lot more expertise than I  who is looking into this. 

[LegitByDefault]

Confrontation is unlikely to work in my opinion and may be hazardous, although that would be the preferable route in a perfect world.

 

Record audio/video showing the interference across channels.
- Note dates/times when it occurs
- If possible, note approximate signal strength or bearings
- Include receiver make/model and settings used

Inform the FCC that an unauthorized station appears to be transmitting on FRS/GMRS using a DMR radio.
- The exact channels and frequencies impacted
- The spurious emissions affecting other channels
- Your location and timeframe of the problem

Accurate and detailed reports are much more likely to be pursued. Reports lacking essential information is half the reason why most complaints go unresolved, the other half being limited enforcement agents, overwhelming quantity of violations nationwide, and time/priority.

 

Depending on your circumstances, there are a variety of methods of reporting that may apply. The best method is through filing a formal enforcement complaint through the FCC’s Enforcement Bureau’s Spectrum Enforcement Division (SED), rather than the consumer informal complaint method. If there's a public safety or business nearby, you can even inquire as to whether or not they have experienced interference and if so, offer to provide them with a copies of your documentation. You can also call the FCC Contact Center directly at 1-888-225-5322 to file a complaint if it's such as this.

 

Otherwise, document it as thoroughly as possible and submit an informal complaint.

[LegitByDefault]

In the off chance they happen to be a member here or they stumble across this thread through a search engine, they should know that their interference has been thoroughly documented over the past month and a formal complaint will be filed if their transmissions doesn't cease. 

[Northcutt114]

Out of curiosity, you say you are "hearing" this interference? If that is the case, it's not DMR. On an analog radio, if someone is transmitting DMR on the same frequency, your analog radio will show a carrier and it will "look" like it's receiving a signal, but you won't hear anything. Now if you try and key up on that same frequency while the DMR radio is also keyed up, you'll hear and experience a lot of interference, but you won't "hear" anything and you definitely won't be able to hear "different voices" if you are on an analog radio.

 

Ignore the above ^. It is incorrect. DMR can be heard on analog radios....but not on ones with a tone programmed on receive. Like mine. 

Also, when you say they are splashing "all over the band from channel 1 -22," do you mean that you are hearing the same disruption on all GMRS channels? or you are hearing different disruptions on different channels?

[OffRoaderX]

26 minutes ago, Northcutt114 said:

On an analog radio, if someone is transmitting DMR on the same frequency, your analog radio will show a carrier and it will "look" like it's receiving a signal, but you won't hear anything.

On (all) of my analog radios i hear DMR as a very loud and very annoying machine-gun-like digital noise.. very, VERY far from "wont hear anything"..

But yah, no voices.

[Northcutt114]

11 minutes ago, OffRoaderX said:

On (all) of my analog radios i hear DMR as a very loud and very annoying machine-gun-like digital noise.. very, VERY far from "wont hear anything"..

But yah, no voices.

Interesting. Hold on. Imma test something real quick.

[SteveShannon]

Here’s what I hear if someone transmits DMR on our 70 cm repeater:

 

 

[Northcutt114]

What if one were running encryption on the DMR channel, might that make a difference? 

 

[SteveShannon]

9 minutes ago, Northcutt114 said:

What if one were running encryption on the DMR channel, might that make a difference? 

 

No, but if you have tone squelch (TSQL) on receive turned on on the analog radio you might not hear the DMR. 

[Northcutt114]

Just now, SteveShannon said:

No, but if you have tone squelch (TSQL) on receive turned on on the analog radio you might not hear the DMR. 

Ah.....that's what it is. I stand corrected and will annotate the original post. I do indeed have a tone on. Just turned it off and yep, there it is. Machine gun static. Thanks for pointing that out @OffRoaderX

[WRUE951]

Yea, there are a few that use DMR on GMRS.. Every once -in-awhile I hear it here in my town but when I travel north I hear it on a regular basis near Fresno and Merced.  A lot of folks up there use it on GMRS repeaters.  Steve's sound bite is exactly what you hear..  

[LeoG]

I was right.

 

About thinking you had a tone going.

 

No proof.  You'll just have to trust me....  Deal with the same issue on many frequencies

 

[SteveShannon]

7 hours ago, WSKK463 said:

The voices change tone - clearly different people communicating

If you hear any kind of voice tones it’s not DMR.  Digital modes convert voices to binary data and send no tones that can be heard on an analog radio.  Make a recording and attach it to a post and we might be able to help you identify the modulation.

[LegitByDefault]

If my radio is sitting idle or scanning, it will open the Squelch but I hear nothing at all. When my Squelch is on (2) I don't hear them but the radio shows RX. The transmissions are barely audible solely via Moni, I can just barely make out something else among the noise - almost indiscernible from the white noise/floor. However, with the volume turned up and RX ENC enabled (Environmental Noise Cancelation) their transmissions are easily audible, but unintelligible.

When I key up I don't hear any interference on my transceiver - pure silence. But if another radio is listening to my transmission emanating from this area, that radio does hear interference... interference that isn't there when I'm outside this area. Same goes for me attempting to listen to other radios that are transmitting from this area. Our transmissions are broken up as if being stepped on I assume. The stations causing interference are quite literally transmitting non-stop back and forth all day long. It's nearly midnight and still going.

As to your last question, I am hearing the same disruptions across all channels, with signal strength fading as I approach channel 22. Same account if going lower than channel 3. I uploaded a short sound recording, which sounds to me more like voice inversion (after doing some yootoob searching)

At the begining and end of recording. Note the noise floor when they cease transmission.

 https://jumpshare.com/s/fPchPR02LOTLj3GABr5w

I don't particularly care that they appear to be using a scrambler - as long as they can hear other transmissions - which they don't seem to be able to and treat the service like they own it. The out of band transmissions and band-wide spurious transmissions throughout each and every day all day long without consideration for others... is unacceptable.

What I meant by "voice tone" earlier is differentiation between male/female/different male/ so on.

 

Occasionally I hear a very low sound wah wah wah similar to what LeoG posted, not nearly as pronounced as SteveShannons audio clip. Although I don't associate that sound with the transmissions causing the issue as it is sparsely heard.

[WRZK526]

9 hours ago, SteveShannon said:

Here’s what I hear if someone transmits DMR on our 70 cm repeater:

 

 

The first part before the beeps is exactly what I hear and it is constantly broadcast. 

[MarkInTampa]

3 hours ago, WSKK463 said:

As to your last question, I am hearing the same disruptions across all channels, with signal strength fading as I approach channel 22.

If your hearing it across all channels at the same time, I'd would think not a GMRS frequency unless it's somebody sitting within a few hundred feet of you overloading the receive on your radio. My guess would be a commercial user very close by on a nearby frequency or your radio is picking up some harmonic of another frequency. If it was a GMRS frequency and strong enough to splatter across all the channels at the same time, you should pick it up S-10 (full signal strength) on the channel they are operating on.

[nokones]

11 hours ago, WRZK526 said:

We have one at 462.537 which interferes with my reception of a repeater at 462.550. I am not sure of the source but we are trying to track it down. Sounds like a digital signal probably DMR. If we locate we will try confrontation and if that doesn't work try FCC which I understand is a long shot. I know someone with a lot more expertise than I  who is looking into this. 

462.5375 MHz is an allocated Business Radio Service freq and being used in a digital trunk system with 100 watt stations on Pinal and Mingus. The AZ GMRS 550 station on White Tanks already operates narrowband. If the other 550 stations operate narrowband and the mobiles and portables set their channels for narrowband, more than likely you wouldn't have any adjacent channel interference from the 462.5375 freq.

In addition to narrowband emissions, if people would use a real radio with a real receiver and not a cheap POS Pandaland Radio with a receiver on a chip, more than likely you wouldn't have that problem.

[WRZK526]

I get that tone from the Cottonwood Camp Verde area, Chino Valley and parts of Prescott AZ when I leave my MXT275 on monitor mode. It only interferes with my reception at 462.550 but my transmissions to repeaters are very well heard (it only interferes with my MXT275 but not my MXT575 or even my handhelds. Just that constant tone. 

[SteveShannon]

24 minutes ago, WRZK526 said:

The first part before the beeps is exactly what I hear and it is constantly broadcast. 

The beeps are our 70 cm repeater automatically IDing itself on analog using Morse code.  It is both a DMR and analog repeater so it’s an easy source of examples of sound.

[WRZK526]

19 minutes ago, nokones said:

462.5375 MHz is an allocated Business Radio Service freq and being used in a digital trunk system with 100 watt stations on Pinal and Mingus. The AZ GMRS 550 station on White Tanks already operates narrowband. If the other 550 stations operate narrowband and the mobiles and portables set their channels for narrowband, more than likely you wouldn't have any adjacent channel interference from the 462.5375 freq.

Thank you! Once I am north of Paulden I lose that signal and do not get it in Flagstaff. I start getting it again going down I-17 when dropping into the Camp Verde area then lose it going south when you climb Mingus on I-17. I talk frequently to the Mt. Eldon 550 repeater, the Porcupine repeater both at .550. Given the line of sight and how the mountains are I can assume it is coming from the Cottonwood area. I know there is a big cement plant in Clarkdale? 

[WRUE951]

41 minutes ago, MarkInTampa said:

If your hearing it across all channels at the same time, I'd would think not a GMRS frequency unless it's somebody sitting within a few hundred feet of you overloading the receive on your radio. My guess would be a commercial user very close by on a nearby frequency or your radio is picking up some harmonic of another frequency. If it was a GMRS frequency and strong enough to splatter across all the channels at the same time, you should pick it up S-10 (full signal strength) on the channel they are operating on.

Time to get the MiniSA out..   

[SteveShannon]

3 hours ago, WSKK463 said:

If my radio is sitting idle or scanning, it will open the Squelch but I hear nothing at all. When my Squelch is on (2) I don't hear them but the radio shows RX. The transmissions are barely audible solely via Moni, I can just barely make out something else among the noise - almost indiscernible from the white noise/floor. However, with the volume turned up and RX ENC enabled (Environmental Noise Cancelation) their transmissions are easily audible, but unintelligible.

When I key up I don't hear any interference on my transceiver - pure silence. But if another radio is listening to my transmission emanating from this area, that radio does hear interference... interference that isn't there when I'm outside this area. Same goes for me attempting to listen to other radios that are transmitting from this area. Our transmissions are broken up as if being stepped on I assume. The stations causing interference are quite literally transmitting non-stop back and forth all day long. It's nearly midnight and still going.

As to your last question, I am hearing the same disruptions across all channels, with signal strength fading as I approach channel 22. Same account if going lower than channel 3. I uploaded a short sound recording, which sounds to me more like voice inversion (after doing some yootoob searching)

At the begining and end of recording. Note the noise floor when they cease transmission.

 https://jumpshare.com/s/fPchPR02LOTLj3GABr5w

I don't particularly care that they appear to be using a scrambler - as long as they can hear other transmissions - which they don't seem to be able to and treat the service like they own it. The out of band transmissions and band-wide spurious transmissions throughout each and every day all day long without consideration for others... is unacceptable.

What I meant by "voice tone" earlier is differentiation between male/female/different male/ so on.

 

Occasionally I hear a very low sound wah wah wah similar to what LeoG posted, not nearly as pronounced as SteveShannons audio clip. Although I don't associate that sound with the transmissions causing the issue as it is sparsely heard.

If I were you, I would contact the nearest ham radio club and ask if they would be interested in helping you identify a source of interference.  Or you could ask the FCC, but the ham club would probably be more responsive.  It might be as simple as a nearby cheap baby monitor. The fact that it’s ongoing makes it easier to find. Once you’ve identified the source of the interference, let the FCC know.