New Repeater Channels for GMRS in 2024

[intermod]

The eight current GMRS channels can handle eight simultaneous conversations today (in the same area).  The proposal below would allow for 32 simultaneous conversations without expanding the GMRS service.

For those not familiar with DMR technology, each DMR repeater signal has two "timeslots" which allows for two independent talk channels.  Two DMR signals can fit within the same space as one analog FM signal today.  This is possible because a DMR signal only requires about 7.6 kHz of spectrum, while todays wideband analog signals need 20 kHz of spectrum.

Thus, four conversations can be supported within each of the current GMRS channels. 

The center frequency of each DMR repeater (and the radios it supports) would be programmed 5 kHz above or below the current center channel.   +/-12.5 kHz might also be used.   

Below shows how this would work in reality. 

The FCC would not need to allocate new radio spectrum.  They only have to allow more efficient use of what we already have.

The other benefit of DMR is that two different repeater groups could invest in one DMR repeater, which splits the cost in two while each maintains their own "channel".   As a DMR repeater takes the same rack space as an analog repeater and only requires one antenna, the repeater site lease costs could be split between the two groups as well.

It would take the FCC some time to accomplish this, so if they started now, they might be able to complete this rule change in 2024.

 

Edited May 29, 2023 by intermod
My poor speeling

[wqnd300]

Why not just take the test for amateur radio if you want to do as there are plenty of dmr repeaters. I'll stick to my p25 radios.

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[intermod]

Are you thinking we want to implement DMR because we want to use digital?   The San Francisco/Sacramento region is heavily congested and interference among repeaters is increasing.   There is no practical solution using the same amount of spectrum unless you move to digital technologies.   

You are also trying to compare apples to oranges.  GMRS is a more attractive solution to the majority of people because their priority is communication as opposed to technical pursuits.  Here in California, CERT, neighborhood or fire watch, militia groups, etc. have implemented GMRS because 80-90% of their members have no direct interest in the technical aspects of amateur radio.

 

[WRUU653]

34 minutes ago, intermod said:

Are you thinking we want to implement DMR because we want to use digital?   The San Francisco/Sacramento region is heavily congested and interference among repeaters is increasing.   There is no practical solution using the same amount of spectrum unless you move to digital technologies.   

You are also trying to compare apples to oranges.  GMRS is a more attractive solution to the majority of people because their priority is communication as opposed to technical pursuits.  Here in California, CERT, neighborhood or fire watch, militia groups, etc. have implemented GMRS because 80-90% of their members have no direct interest in the technical aspects of amateur radio.

 

And of course no one will have to buy new radios to use this because the old ones will still be compatible with these new proposed specs and the FRS bubble packs out there shouldn’t be an issue either… It sounds like something that the people who sell radios would be behind though.

[SteveShannon]

DMR channels do not use 7.6 kHz of spectrum; they each use 12.5 kHz but they use time division multiplexing to share that portion of spectrum. In other words each current GMRS channel would only represent two DMR channels. 
Gil is correct that this would impact everyone who has an analog GMRS radio. Use of such a radio requires the entire channel, making it unavailable for DMR.  
Conversely, to those who have analog radios, every DMR transmission sounds like an impact wrench.

“Here in California, CERT, neighborhood or fire watch, militia groups, etc. have implemented GMRS because 80-90% of their members have no direct interest in the technical aspects of amateur radio.”

I don’t know how true that statistic is, but ruining GMRS for the rest of us isn’t the answer. 
 

P.S.  People who have no direct interest in the technical aspects of amateur radio might have a tough go when they have to program a codeplug. DMR codeplugs are extremely technical. I guess you could sell the radio with a basic codeplug that’s simplex DMR on 1-22 and duplex on 23-30, but what do you use for talk groups, time slots, and color codes?

[WQAI363]

2 hours ago, intermod said:

The eight current GMRS channels can handle eight simultaneous conversations today (in the same area).  The proposal below would allow for 32 simultaneous conversations without expanding the GMRS service.

For those not familiar with DMR technology, each DMR repeater signal has two "timeslots" which allows for two independent talk channels.  Two DMR signals can fit within the same space as one analog FM signal today.  This is possible because a DMR signal only requires about 7.6 kHz of spectrum, while todays wideband analog signals need 20 kHz of spectrum.

Thus, four conversations can be supported within each of the current GMRS channels. 

The center frequency of each DMR repeater (and the radios it supports) would be programmed 5 kHz above or below the current center channel.   +/-12.5 kHz might also be used.   

Below shows how this would work in reality. 

The FCC would not need to allocate new radio spectrum.  Thy only have to allow more efficient use of what we already have.

The other benefit of DMR is that two different repeater groups could invest in one DMR repeater, which splits the cost in two while each maintains their own "channel".   As a DMR repeater takes the same rack space as an analog repeater and only requires one antenna, the repeater site lease costs could be split between the two groups as well.

It would take the FCC some time to accomplish this, so if they started now, they might be able to complete this rule change inur 2024.

 

DMR on the General Mobile Radio Service Band sounds good, but not all GMRS users are really familiar with DMR. I mean not all GMRS license holders are also Amateur Radio License holders. I do forget the one manufacture of an FRS radios that have digital capability, but what format ? I want to say Retevis, but I could be wrong. Anyway, I know it isn't any of the other manufactures, such Midland or Motorola. Of course, I would sell all the vertex radios I own to buy Motorola GMRS Mobile if they came out with one, but I have better chance of seeing the Dodgers move back to Brooklyn before Motorola produce a GMRS mobile radio. I kind of dabbled with on FRS low power of course, just to hear my voice over my Scanner. I used channel 01 and 07 just brief test which is technically violating FCC regulations somewhere, but I would not use it unless the R&R changes to allow.

[wqnd300]

Are you thinking we want to implement DMR because we want to use digital?   The San Francisco/Sacramento region is heavily congested and interference among repeaters is increasing.   There is no practical solution using the same amount of spectrum unless you move to digital technologies.   
You are also trying to compare apples to oranges.  GMRS is a more attractive solution to the majority of people because their priority is communication as opposed to technical pursuits.  Here in California, CERT, neighborhood or fire watch, militia groups, etc. have implemented GMRS because 80-90% of their members have no direct interest in the technical aspects of amateur radio.
 

Then stop putting repeaters on top of other repeaters! Simple solution because you don't need more than a few. Here in Southern California we have idiots that need to shut up and allow others to periodically use the frequency. Those are the real issues.

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[Lscott]

29 minutes ago, wqnd300 said:

Then stop putting repeaters on top of other repeaters! Simple solution because you don't need more than a few. Here in Southern California we have idiots that need to shut up and allow others to periodically use the frequency. Those are the real issues.

Sent from my SM-S918U using Tapatalk
 

One other point. Just how many people check to see if they can reliably communicate using simplex? If they can then they should stay off the repeater, use simplex, and let those who REALLY need it the access. 

[wqnd300]

One other point. Just how many people check to see if they can reliably communicate using simplex? If they can then they should stay off the repeater, use simplex, and let those who REALLY need it the access. 

The issue from what I have heard is people use the same frequency and tone as the repeater then when someone gets on the repeater they get yelled at for it. But yes if you had a decent base radio you could get some distance even simplex.

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[Lscott]

3 hours ago, wqnd300 said:

The issue from what I have heard is people use the same frequency and tone as the repeater then when someone gets on the repeater they get yelled at for it.
 

I guess you can’t fix stupid. 

[axorlov]

3 hours ago, wqnd300 said:

The issue from what I have heard is people use the same frequency and tone as the repeater then when someone gets on the repeater they get yelled at for it

Happened to me two or three times. But it was a bit worse, I was using DCS to communicate with my family, and people listening to the repeater did not have Rx tone (as recommended many times on this board, LOL!). While not a major trouble, it can be a nuisance. Especially, if someone with a little understanding of radio, but with overinflated sense of social responsibility decides to act as a rule enforcer.

[nokones]

7 hours ago, Lscott said:

I guess you can’t fix stupid. 

Nor regulate it.

[UncleYoda]

I hate everything about DMR.  I particularly hate the way it's taking up frequencies in HAM.  I would file for a refund of my GMRS fee if the FCC implemented your proposal.  Digital should get its own bands and not take over our analog frequencies.

[WRQC527]

I don't know about the rest of you, but here in SoCal, we have a repeater at almost 6,000 feet that sits unused the vast majority of the time, in addition to others that are not used a lot. The traffic I hear even on simplex as I drive 50 miles a day commuting is pretty sparse, mostly preschools, restaurants, Covid shot clinics, that kind of thing, on FRS. I'm not sure why we would want to introduce digital to GMRS. All it would do is run up the price of radios and overcomplicate things. In my humble opinion, people get into GMRS because it's cheap, reliable, and doesn't require a test.

[WRQI583]

While it sounds like a good idea, with GMRS being unregulated when it comes to setting up repeaters, it would, in some areas cause bad problems. GMRS would have to turn all digital or stay all analog. With the amount of bubble pack radios out there doing analog, it wouldn't make sense to have it change to DMR. In my area alone, we are maxed out on GMRS repeaters when it comes to the 8 pairs, which rarely get used. The majority of the communications you hear are businesses and schools on the bubble pack radios. Adding DMR to that would cause a real issue. 

I am not against DMR. It is the only digital voice mode I use on Ham Radio and I absolutely love it. For the GMRS application, if DMR were to be introduced as the sole means of communication, that would have had to have happened back before they flooded the market with bubble pack radios. Back in the day where GMRS was GMRS and FRS didn't exist. I think what the FCC should do is find a set of frequencies near GMRS and give us another 8 just for DMR. With everyone abandoning the VHF and UHF lower portions of the bands to get on 800 MHz and also with the FirstNet network, there are going to be a lot of empty frequencies across the nation. The VHF low band is a good example. For $35 a license, I think they can spare some. DMR is a good idea when it comes to utilizing bandwidth, plus, you can add networks to it. But, like many will say, that is what you have Ham Radio for. While that is true, I think more people would utilize radio if they could have that element of Ham Radio, but without having to take a test.

[WRUU653]

It seems someone always wants to change GMRS. 
Other ideas I don’t think would work… painting two lanes for cars but trucks get there own overlapping lane to drive down the middle… yeah but it’s more lanes and cars can fit there, doesn’t it sound great?
 

[WRUU653]

44 minutes ago, WRQC527 said:

I don't know about the rest of you, but here in SoCal, we have a repeater at almost 6,000 feet that sits unused the vast majority of the time, in addition to others that are not used a lot. The traffic I hear even on simplex as I drive 50 miles a day commuting is pretty sparse, mostly preschools, restaurants, Covid shot clinics, that kind of thing, on FRS. I'm not sure why we would want to introduce digital to GMRS. All it would do is run up the price of radios and overcomplicate things. In my humble opinion, people get into GMRS because it's cheap, reliable, and doesn't require a test.

This is close to how things are here north of you. We have a few really good repeaters with some new ones added recently. It’s not saturated but spread out giving better coverage which is nice. It’s still fairly quiet though. Some FRS construction workers, Kids on lower FRS channels (they’re having fun), preschool workers, people vacation traveling… but relatively quiet especially on the repeaters.  Most traffic is still on ham. Something for everyone. 

[Guest]

1 hour ago, WRQC527 said:

[...], people get into GMRS because it's cheap, reliable, and doesn't require a test.

... and "out of the box / instant" FUN !!!

Case closed

[intermod]

17 hours ago, Sshannon said:

DMR channels do not use 7.6 kHz of spectrum; they each use 12.5 kHz but they use time division multiplexing to share that portion of spectrum. In other words each current GMRS channel would only represent two DMR channels. 
Gil is correct that this would impact everyone who has an analog GMRS radio. Use of such a radio requires the entire channel, making it unavailable for DMR.  
Conversely, to those who have analog radios, every DMR transmission sounds like an impact wrench.

Not sure I understand your comment.  Are you confusing channel steps or spectrum allocation with signal bandwidth?   The 7.6 kHz is from the official emission designator, as is 20kHz for analog.   That means ~99% of the power is within these bandwidths.   So one can easily fit two DMR signals in the same or less bandwidth of the wideband analog signal and get 2X2 or 4 timeslots (or usable channels).  

[Lscott]

2 hours ago, WRQI583 said:

GMRS would have to turn all digital or stay all analog.

Not necessarily. The key is how it’s done and what digital mode.  

While I like DMR I don’t think it’s a good candidate to use on GMRS. I believe there are a couple of better choices. As a few other posts have pointed out the principle issues are the existing base of analog radios and just where do you locate the digital channels where they would result in the least interference to analog operations.

[intermod]

18 hours ago, WRUU653 said:

And of course no one will have to buy new radios to use this because the old ones will still be compatible with these new proposed specs and the FRS bubble packs out there shouldn’t be an issue either… It sounds like something that the people who sell radios would be behind though.

This plan would not replace analog - both would be permitted.  Analog is never going away.   The people wanting to use digital must get a digital radio.  But there is no need for anyone else to do this.   For example, if I have a analog repeater today, and I need more capacity, I have two options.   Replace it with a DMR repeater on the current 462.625 channel center, or move it +/- 5 kHz up or down.  The former is really a waste of spectrum.   The latter would provide me with two channels, and leave the other half of the channel open for another DMR repeater if another group wants their own repeater.    

[Lscott]

4 minutes ago, intermod said:

So one can easily fit two DMR signals in the same or less bandwidth of the wideband analog signal and get 2X2 or 4 timeslots (or usable channels).  

That’s only true if the radios are able to “effectively” coordinate time slot synchronization between themselves. Usually the repeater does that task. On simplex that has to be done by the user’s radio. The feature is typically referred to as DCDM, dual capacity direct mode. Some radios will just transmit on both time slots in simplex mode.

[intermod]

15 hours ago, wqnd300 said:

Then stop putting repeaters on top of other repeaters! Simple solution because you don't need more than a few. Here in Southern California we have idiots that need to shut up and allow others to periodically use the frequency. Those are the real issues.

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You guys in the south are suffering worse than we are due to the terrain (bowls circled by huge mountains).  DMR is the perfect solution to expand GMRS in Socal by providing 4X the spectrum.  And you can place DMR repeaters close together compared to analog, so this provide even ore benefit.

In Norcal, we have a somewhat greater number of smaller "bowls" and more mountain ranges and hills, but many are lower.   So to get any reasonable range, you need more repeaters.    

Maybe another solution would be to reduce repeater transmit power based on repeater elevation; the higher the elevation, the lower the power you could run.   They already do this in UHF, 800 and 900 MHz business bands.            

[intermod]

15 hours ago, Lscott said:

One other point. Just how many people check to see if they can reliably communicate using simplex? If they can then they should stay off the repeater, use simplex, and let those who REALLY need it the access. 

Agree with that....this is one benefit of amateur radio; more licensees understand the concepts.   We should educate our GMRS licensees better.      

[intermod]

11 hours ago, axorlov said:

Happened to me two or three times. But it was a bit worse, I was using DCS to communicate with my family, and people listening to the repeater did not have Rx tone (as recommended many times on this board, LOL!). While not a major trouble, it can be a nuisance. Especially, if someone with a little understanding of radio, but with overinflated sense of social responsibility decides to act as a rule enforcer.

Was her name Karen?