Heard DMR on an FRS channel for the first time Yesterday!

[RFI-EMI-GUY]

I have three of the Icom 4008A's Two I bought new, they are wonderful and verry rugged radiis. Yes the antenna is worriesome, but mine are still fine. I have some other brand FRS radios and those, the rubber buttons and bumpers turned bad oozed, and finally fell apatr.

 

[902]

I have three of the Icom 4008A's Two I bought new, they are wonderful and verry rugged radiis. Yes the antenna is worriesome, but mine are still fine. I have some other brand FRS radios and those, the rubber buttons and bumpers turned bad oozed, and finally fell apatr.

We're bad for rubber ooze down here. I have quite a few things that ended up like that, especially mic cords that break down in a hot car.

 

[N4KVE]

Nailed it! And it'll just get worse, "good buddies".

Just listen to the NA TG. DMR CB. Most with Tytera radios. Straight from a life on 27 MHz. Talk around the world for $104. 10-4 good buddy.

 

[RFI-EMI-GUY]

DMR is in fact transmitted using FM. The proper inquiry is whether or not this type of encoding of the voice signal is permitted in FRS.

GMRS

(a) A GMRS transmitter must transmit only emission types A1D, F1D, G1D, H1D, J1D, R1D, A3E, F3E, G3E, H3E, J3E or R3E. A non-voice emission is limited to selective calling or tone-operated squelch tones to establish or continue voice communications. See § 95.181 (g) and (h).

See the problem?

K00F1D NXDN 6.25 kHz data (IDAS, NEXEDGE)
4K00F1E NXDN 6.25 kHz digital voice (IDAS, NEXEDGE)
4K00F1W NXDN 6.25 kHz digital voice and data (IDAS, NEXEDGE)
4K00F2D NXDN 6.25 kHz analog FM CW ID (IDAS, NEXEDGE)

8K10F1D P25 Phase I C4FM data
8K10F1E P25 Phase I C4FM voice

7K60FXD 2-slot DMR (Motorola MOTOTRBO) TDMA data
7K60FXE 2-slot DMR (Motorola MOTOTRBO) TDMA voice

And none of the above digital mode radio models are part 95 certified anyway.

 

[DaveNF2G]

Yes, I do see the problem. A strict reading of the regs suggests that all of the above protocols are allowed on GMRS (although not necessarily on FRS). But, as you say, there are no radios that use those protocols that may lawfully be used for GMRS.

 

[RFI-EMI-GUY]

Look closer, none of those emission types permit a digital voice. Digital squelch yes.

 

[bharvey2]

I don't think the DMR users on GMRS frequencies are limited to the cheap DMR radios. In planning my trip to the midwest last summer, I checked the mygmrs.com website for repeaters in the area. I saw a few repeaters that specified that they were using DMR. I thought it was pretty brazen and I don't see them listed now. Perhaps that got spanked and sent to their room or got enough heat about breaking the law.

On a related note, some of the GMRS repeater trustees in my area have made it known that if the FCC ever permits DMR emissions on GMRS frequencies, they intend to switch over from analog. - It's not happening here yet though.

 

[RFI-EMI-GUY]

I don't think the DMR users on GMRS frequencies are limited to the cheap DMR radios. In planning my trip to the midwest last summer, I checked the mygmrs.com website for repeaters in the area. I saw a few repeaters that specified that they were using DMR. I thought it was pretty brazen and I don't see them listed now. Perhaps that got spanked and sent to their room or got enough heat about breaking the law.

On a related note, some of the GMRS repeater trustees in my area have made it known that if the FCC ever permits DMR emissions on GMRS frequencies, they intend to switch over from analog. - It's not happening here yet though.

Personally; I think DMR offers a lot of advantages with respect to networking and the FCC should be petitioned to permit it on secondary basis.

The only problem is that the current 25KHz BW FM offers a lot of interoperability that could be forfeited with digital.

If the FCC permits DMR, then NXDN and P25 will follow. No doubt the manufacturers will want to push Fusion and DStar and whatever. Then we will have no interoperability. The other risk is that one manufacturer might create a quasi-commercial network and take over the channels in metro areas.

So any petition should be well though out and be designed to benefit the licensed user base.

 

[902]

Personally; I think DMR offers a lot of advantages with respect to networking and the FCC should be petitioned to permit it on secondary basis.

The only problem is that the current 25KHz BW FM offers a lot of interoperability that could be forfeited with digital.

If the FCC permits DMR, then NXDN and P25 will follow. No doubt the manufacturers will want to push Fusion and DStar and whatever. Then we will have no interoperability. The other risk is that one manufacturer might create a quasi-commercial network and take over the channels in metro areas.

So any petition should be well though out and be designed to benefit the licensed user base.

But, it's GMRS. It all has to be shared among all the users in any given area. You and I could live across the street from each other and you could have your repeater and tone on a tower behind your house, and I could have my repeater and tone on a tower behind my house. We could be on the same frequency. But we effectively share air time.

DMR does not share well. In fact, it changes the use characteristics significantly, especially when the other timeslot is used for polling, like AVL or some networked talkgroup.

 

[RFI-EMI-GUY]

But, it's GMRS. It all has to be shared among all the users in any given area. You and I could live across the street from each other and you could have your repeater and tone on a tower behind your house, and I could have my repeater and tone on a tower behind my house. We could be on the same frequency. But we effectively share air time.

DMR does not share well. In fact, it changes the use characteristics significantly, especially when the other timeslot is used for polling, like AVL or some networked talkgroup.

True but;

1. You and I could share expenses for one repeater and one tower and each have entirely separate time slots from each other and never know the other is utilizing the channel. This would be a tremendous cost savings, money that could be pocketed or put to use to install a second repeater at a remote area and link via IP. FDMA Conventional P25, Fusion and D-Star do not offer all of that savings and utility.

2. Hmm Ok yes I can see the point that if there is a lot of traffic, the channel will be busy. But what is the alternative? NXDN? NXDN does not share well in many cases either. When trying to find a clear 12.5 KHz Part 90 channel in south Florida, many are assigned to a single offset 6.25 KHz NXDN, leaving room for what- only another NXDN (clever).

In reality GMRS is under utilized and is susceptible to the whims of the FCC and those who lobby them. This little 400 KHz slice of 462/467 MHz farmland is in the way of the larger 30 lane tollway. It needs to be utilized to a better extent.

 

[902]

True but;

1. You and I could share expenses for one repeater and one tower and each have entirely separate time slots from each other and never know the other is utilizing the channel. This would be a tremendous cost savings, money that could be pocketed or put to use to install a second repeater at a remote area and link via IP. FDMA Conventional P25, Fusion and D-Star do not offer all of that savings and utility.

2. Hmm Ok yes I can see the point that if there is a lot of traffic, the channel will be busy. But what is the alternative? NXDN? NXDN does not share well in many cases either. When trying to find a clear 12.5 KHz Part 90 channel in south Florida, many are assigned to a single offset 6.25 KHz NXDN, leaving room for what- only another NXDN (clever).

In reality GMRS is under utilized and is susceptible to the whims of the FCC and those who lobby them. This little 400 KHz slice of 462/467 MHz farmland is in the way of the larger 30 lane tollway. It needs to be utilized to a better extent.

1. That makes sense. And it goes against all of the GMRS repeater wars of the last three decades. Like programming the Zetron to pass audio on one CDCSS with a different CDCSS code in, and then key up the repeater on every other tone and code and just transmit channel marker beeps. Or, putting LTR controllers on the repeater for three HTs and two mobiles. I know people who did that (and also detuned the input by 12.5 kHz to foul up everyone else). All those wars could have been solved with a product that worked ten times better if people worked together... but...

2. Anything that's networked is going to be a resource hog unless there is an affiliation scheme. It's like Schrödinger's cat. The channel can be used or not used. It all depends on affiliation. Affiliate and it's used. No affiliate and it's quiet. I'd favor that more than, say, "North America" where one conversation between two people can make electric meters around the world spin. If it's not networked, it should follow regular LMR usage patterns.

But you hit on an important point -

GMRS absolutely does need to get used - and in more than just blisterpacked radios that say they have 80V batteries and you can talk for 125 miles on the package - or it will become part of the 90.35 spectrum in no time.

Personally, I don't think I had a better communications network - ham included - than I had with a couple of buddies in the early 90s who had two Micor GMRS repeaters with Zetron Model 38 panels. I had two Sabers and a few HT600 portables, a Syntor X-9000 and a couple of Maxtrac mobiles. My girlfriend at the time was on there, and so were most of my friends. Things change.

 

[ecps92]

Then add the Repeater on 467 with a 462 input :roll:

1. That makes sense. And it goes against all of the GMRS repeater wars of the last three decades. Like programming the Zetron to pass audio on one CDCSS with a different CDCSS code in, and then key up the repeater on every other tone and code and just transmit channel marker beeps. Or, putting LTR controllers on the repeater for three HTs and two mobiles. I know people who did that (and also detuned the input by 12.5 kHz to foul up everyone else). All those wars could have been solved with a product that worked ten times better if people worked together... but...

2. Anything that's networked is going to be a resource hog unless there is an affiliation scheme. It's like Schrödinger's cat. The channel can be used or not used. It all depends on affiliation. Affiliate and it's used. No affiliate and it's quiet. I'd favor that more than, say, "North America" where one conversation between two people can make electric meters around the world spin. If it's not networked, it should follow regular LMR usage patterns.

But you hit on an important point -

GMRS absolutely does need to get used - and in more than just blisterpacked radios that say they have 80V batteries and you can talk for 125 miles on the package - or it will become part of the 90.35 spectrum in no time.

Personally, I don't think I had a better communications network - ham included - than I had with a couple of buddies in the early 90s who had two Micor GMRS repeaters with Zetron Model 38 panels. I had two Sabers and a few HT600 portables, a Syntor X-9000 and a couple of Maxtrac mobiles. My girlfriend at the time was on there, and so were most of my friends. Things change.

 

[toastycookies]

GMRS

K00F1D NXDN 6.25 kHz data (IDAS, NEXEDGE)
4K00F1E NXDN 6.25 kHz digital voice (IDAS, NEXEDGE)
4K00F1W NXDN 6.25 kHz digital voice and data (IDAS, NEXEDGE)
4K00F2D NXDN 6.25 kHz analog FM CW ID (IDAS, NEXEDGE)


And none of the above digital mode radio models are part 95 certified anyway.

 

[ecps92]

Typical Sales flyer, what are you trying to say :roll:
Don't see Part 95 anywhere.. so it is not LEGAL on GMRS

 

[toastycookies]

Typical Sales flyer, what are you trying to say :roll:
Don't see Part 95 anywhere.. so it is not LEGAL on GMRS

:roll:

 

[bharvey2]

Personally; I think DMR offers a lot of advantages with respect to networking and the FCC should be petitioned to permit it on secondary basis.

So any petition should be well though out and be designed to benefit the licensed user base.

I like the idea of allowing DMR on GMRS in concept but you are right, it would need to be well thought out. In my area (San Francisco Bay Area) There are a fair amount of repeaters but they aren't used too much. Also give the topography, you can drive over a hill and lose access to a repeater. If DMR were in place and the repeaters were networked, a very reliable and wide area network could be established as long as everyone played nice. I could see the appeal for that.

 

[N4GIX]

The Flom report above has a typographical error in the first two lines. The frequencies should be 462.7250.

I'm still not convinced that NXDN would be legal on GMRS frequency pairs. Analog 25MHz yes, but digital no. Also, from the prototype images shown in the application's supporting documents, it is not even the same radio as the NX200/300 as shown in the above brochure.

https://fccid.io/ALH378500

 

[PACNWDude]

I once had to reign in a military unit that was using encrypted radios on FRS frequencies since their spectrum manager never gave them any other frequencies to use. This fell under NTIA instead of FCC.

But nothing really surprises me these days. Plenty of people have the money and resources to use high end gear incorrectly, just as often as those using cheap Chinese gear.

In my area a local fire department complained about interference. I found it to be from the local police department. It was a programming error, and they used the same vendor at both departments.

 

[toastycookies]

The Flom report above has a typographical error in the first two lines. The frequencies should be 462.7250.

I'm still not convinced that NXDN would be legal on GMRS frequency pairs. Analog 25MHz yes, but digital no. Also, from the prototype images shown in the application's supporting documents, it is not even the same radio as the NX200/300 as shown in the above brochure.

https://fccid.io/ALH378500

nobody is saying NXDN is legal on GMRS AT ALL!

Multiple people said there were no digital (specifically NXDN) Part 90 radios legally capable on Part 95 frequencies.

I just corrected them.

THERE ARE PART 90 DIGITAL NXDN RADIOS THAT ARE ALSO PART 95 TYPE ACCEPTED.

THEY ARE NOT LEGAL TO USE (unpermitted) DIGITAL MODES ON PART 95.

THEY ARE PART 95 TYPE ACCEPTED.

tl;dr = THERE ARE NXDN DIGITAL RADIOS PART 90 AND 95 TYPE ACCEPTED.

THE FCC ID NUMBERS SHOW PROOF OF EMISSIONS TYPE ACCEPTANCE.

Please people just look to the FCC for this stuff. They have a website you know. Spreading false rumors around these forums is just ignorant.

 

[RFI-EMI-GUY]

That is interesting to note.

See the Grant note: "EF This device may contain functions that are not operational in U.S Territories except as noted in the filing. This grant has extended frequencies as noted in the filing and Section 2.927(b) applies to this authorization."

As a historic aside, I have reviewed the FCC Grant for the Motorola Systems Sabers. They are approved for Part 95 though they also have Securenet DES encryption capability that is also not permitted.

I have seen of late, the FCC rubber stamping anything that gets thrown over the transom. This includes even some cheap Motorola equipment that operates DC to daylight with Grant Note EF.

The FCC is pretty adamant about not approving some multi service radios, yet their OET goes on doing their thing with a rubber stamp. Now there are off shore labs certifying those cheap Chinese radios and the OET doesn't care.