New Repeater Channels for GMRS in 2024

[nokones]

It is given that the FCC has mandated that the FRS and GMRS radio services will share the spectrum between 462.550 MHz and 462.725 MHz, and 467.550 MHz and 467.725 MHz with voice modulation in the analog emissions mode.

With the exception of a few large Metropolitan Regions, the smaller regional areas in the future may warrant additional GMRS channels due to the growth of the hobby.

In my opinion, and for keeping the cost of this GMRS hobby affordable for people with less disposable income, most technological advancements such as, digital emissions for voice, etc., will drive up the cost and complexity of the hobby. 

Most people would like to keep the cost down and simple so they can have adequate voice radio communications.

Allowing technical improvements like digital voice will not provide any additional benefit that analog emissions does today. People are communicating very effectively in the analog mode on the GMRS channels.

If hobbyists/radio users want to indulge in the technical aspects of two-way radio, than the Amateur Radio Service is the play to go. The Amateur Radio Service is the Band where people can build, fabricate, experiment, engineer, tear apart, re-engineer, put back together to see if it will work, have digital voice emissions, and share their experiences with other people who likes to fiddle with the inner-workings of radio communication devices and have plenty of spectrum on several frequency bands to do the fiddling around.  

The GMRS Radio Services is not the place to do HAM stuff and things. That is why there is Amateur Radio Services.

Sometimes, I question the need of 14 FRS radio channels. Is there really 14 simultaneous FRS conversations occurring in the same proximity with such low-powered devices with a gazillion privacy tones available and of course the conversations are not private? I doubt it.

I believe FRS can effectively be used with a lot less radio channels, like MURS. Also, I believe allowing the reduced FRS channels operate at the two-watt output power level the 462 MHz channels could live adequately with the GMRS channels.

Giving the FRS users the use of the existing channels 1-7 at two-watts and taking away channels 8-14 would not be a dis-service to the FRS users.

I would like to see the FCC mandate that the main GMRS channels be reallocated to 2.5 KHz/12.5 KHz channels and the interstitial channels be reallocated for GMRS 50 watt use and several channel pairs designated for use only at lower HAAT elevations.

By reallocation the channels to narrowband would provide a lot more channel capacity with less channel and user interferences and provide for future growth.

The reforming of the Part 90 allocated radio channels did not cause any problems and I feel that the GMRS channels can be just as successful with narrowband. Eventually, GMRS may be forced into narrowband in the future, so let's get'r dun!

[WRQI583]

1 hour ago, Sshannon said:

Our local Hytera 70cm repeater is both DMR and analog.  It seems to work well.  The repeater give preference to analog communications. Our Monday  evening 2 meter net has moved to this repeater using 70 cm analog because our 2 meter Yaesu DR1 is locked up and the mountain top site is not accessible without a helicopter. People watching the mountain have noticed that avalanches have taken place.

It’s first come, first served, like any repeater. When people are using the repeater for analog both time slots of DMR are blocked. When people are using either time slot for DMR no analog transmissions can take place. Technically that’s probably not considered interference; it’s just the limitations of the technology. After all, when a person is on an analog repeater no other analog transmissions can take place either. The coordination that you mentioned is all of our responsibility; we should not hog the repeater. The vulnerability to being blocked is something that currently exists.  Changing to DMR would not change that. 

 

And that is the problem. You're going to have a bunch of guys with digital radios who are going to get on there and chat up a storm and I will tell you that it is horribly annoying to listen to digital coming over your radio. We have this problem with yaesu fusion where I live. They need to keep the digital out of gmrs. If you want digital go to ham radio, there's a huge world of it to play with. Ham radio has already been destroyed by the digital voice modes because there's so many different forms and repeaters and not everybody can afford the equipment. And then how many forms of digital are we going to introduce into gmrs? Is it going to be like ham radio where I'm going to have to have a p25 radio and a nxdn radio and a DMR radio and a fusion radio? and the list goes on. That's a ham radio thing and it needs to be left where it is. If gmrs-ham operators want digital then they need to stay on ham or create their own gmrs band with digital only. Having digital and analog segregates the population of people who are on the radio. I see it already in ham radio. You have us DMR operators and then you have the fusion operators and I can't talk to one unless I have what they have and they can't talk to me unless they have what I have and neither of us will budge and get the other radio. The radio is not what's the blame, it's the radio operators and unfortunately none of them will change.

I know from experience living right near very good wide coverage repeaters that are digital that I can't afford the equipment for and it limits me. If things went digital that means I have to buy two brand new radios, possibly 4, just to use whatever form of digital it runs on. It brings up a good question, when is this all going to stop? When are people just going to get on the radio and use it and stop trying to have the latest and the greatest? I thought that was ham radio? I thought that wasn't going to filter into gmrs. 

[Lscott]

47 minutes ago, WRQI583 said:

Is it going to be like ham radio where I'm going to have to have a p25 radio and a nxdn radio and a DMR radio and a fusion radio?

I’m all set. I have everything, including D-Star you forgot to list, except for a System Fusion radio.

[WRQI583]

49 minutes ago, Lscott said:

I’m all set. I have everything, including D-Star you forgot to list, except for a System Fusion radio.

Well for those of us that have limited money, limited room for more radios and definitely antennas, that will exclude us. Feels like ham radio all over again.

[intermod]

3 hours ago, Sshannon said:

My only objections to the OP’s initial post are that four DMR channels cannot fit into the space of one analog channel (only two can, but that’s still a benefit).... 

Currently emission type F1D, F3E, and F2D are all permitted (along with quite a few others). Two slot DMR can be done on F1D and F2D.  I’m not sure what part of the regulations make it prohibited to use DMR on GMRS frequencies now, but I suspect I just don’t recall the right paragraph.

 

You may be mixing up channels and slots (or talkpaths).   You are correct  - two DMR carriers/signals can fit within a single analog carrier.   That is what the chart shows.  But each DMR carrier/signal provides two simultaneous talk paths, correct?   So you end up with four talk paths in the same amount of spectrum as one FM signal that can only support one talk path. 

A DMR repeater requires F7D and F7E.  DMR handheld and vehicular radios require F1D and F1E.  Only the F1D is permitted (so you can operate DMR on GMRS for non-voice - like texting).   

They key here is the "E" for Telephony (voice) versus 'D" for Data transmission.

The "7" indicates "more than one channel" of information is being carried (the repeater has two timeslots).  The handheld and vehicular radios use "1" because they only can talk on one slot at a time.      

 

[SteveShannon]

1 minute ago, intermod said:

You may be mixing up channels and slots (or talkpaths).   You are correct  - two DMR carriers/signals can fit within a single analog carrier.   That is what the chart shows.  But each DMR carrier/signal provides two simultaneous talk paths, correct?   So you end up with four talk paths in the same amount of spectrum as one FM signal that can only support one talk path. 

No, each DMR channel has a spectrum bandwidth of 12.5 kHz which is time divided into two channels. That’s the only way the two DMR signals fit within a single analog 12.5 kHz channel. They’re not 6.25 kHz channels. If they were I would agree that you could squeeze in four. 

[SteveShannon]

2 hours ago, WRQI583 said:

You're going to have a bunch of guys with digital radios who are going to get on there and chat up a storm and I will tell you that it is horribly annoying to listen to digital coming over your radio.

It won’t be happening anytime soon and if you go back read my post more carefully you’ll realize that I am neutral; I’m not advocating for or against. I’m just pointing out considerations. 
But don’t you already have the same problem with people chatting on the radio?

If not, and if allowing DMR will cause an influx of users, isn’t that an argument for DMR?  

[WRQI583]

1 hour ago, Sshannon said:

It won’t be happening anytime soon and if you go back read my post more carefully you’ll realize that I am neutral; I’m not advocating for or against. I’m just pointing out considerations. 
But don’t you already have the same problem with people chatting on the radio?

 If not, and if allowing DMR will cause an influx of users, isn’t that an argument for DMR?

The point is that it will happen. My question is why Ham operators and others who want Ham radio without taking a test cant just stay on their own bands and stop trying to turn GMRS into another Ham band that they can destroy. 

From my experience, DMR is not a digital voice mode that will cause an influx of users. You should hear the Hams who have a nuclear meltdown because they cant write a code plug. How many of them have floated off to Yaesu Fusion because its as simple as hitting a button and talking digital? DMR came easy to me. First time ever, I wrote a code plug like it was nothing. Not everyone is like that. Most people get confused when it comes to DMR.

The point is, GMRS is just fine the way it is. Either GMRS would need to be all digital or all analog, not a mix. If mixing digital and analog worked, I would have many more repeaters programmed in my radio, but it doesn't.

[intermod]

22 hours ago, Sshannon said:

No, each DMR channel has a spectrum bandwidth of 12.5 kHz which is time divided into two channels. That’s the only way the two DMR signals fit within a single analog 12.5 kHz channel. They’re not 6.25 kHz channels. If they were I would agree that you could squeeze in four. 

Yet I never said I could squeeze in four .  

Strangely, I think we are in agreement here, however.   

Just one example.  There channels in the VHF and UHF commercial bands remain 25 kHz wide like GMRS (see 152.72 MHz, 454.350 MHz, etc.).  These are under FCC Part 22, not Part 90.  Within the 454.350 channel we placed one DMR signal 6.25 kHz below and one 6.25 kHz above the center at 454.350.   So that provides for four simultaneous conversation paths (four slots).   

I am currently experimenting with placing a third DMR signal centered on 454.350 MHz, but geographically separated from the other two to limit adjacent channel interference.  So far this is working great as long as the separation is adequate.  

[Lscott]

20 hours ago, WRQI583 said:

The point is that it will happen. My question is why Ham operators and others who want Ham radio without taking a test cant just stay on their own bands and stop trying to turn GMRS into another Ham band that they can destroy. 

From my experience, DMR is not a digital voice mode that will cause an influx of users. You should hear the Hams who have a nuclear meltdown because they cant write a code plug. How many of them have floated off to Yaesu Fusion because its as simple as hitting a button and talking digital? DMR came easy to me. First time ever, I wrote a code plug like it was nothing. Not everyone is like that. Most people get confused when it comes to DMR.

The point is, GMRS is just fine the way it is. Either GMRS would need to be all digital or all analog, not a mix. If mixing digital and analog worked, I would have many more repeaters programmed in my radio, but it doesn't.

IMHO allowing some form of digital voice on part, or all, of GMRS is about a better quality of service. Digital voice doesn’t really increase range to a large degree but provide a near noiseless audio signal over more of that range whereas analog FM becomes difficult to copy.

While people mention DMR IMHO that isn’t the best mode. In a prior post in this thread I posted an attachment PDF going into some detail on where and how digital voice could be added without a major disruption to existing FM operations. I would encourage you to read it. Particularly the last few paragraphs and links.

[SteveShannon]

17 minutes ago, intermod said:

Yet I never said I could squeeze in four .  

From your first post:

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

But the experiments you’ve done are very interesting and I enjoy hearing about them.

[intermod]

2 hours ago, Sshannon said:

From your first post:

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

But the experiments you’ve done are very interesting and I enjoy hearing about them.

And this is true.  Each slot can carry an independent and simultaneous conversation.  If I have 2 DMR signals or carriers, 2 slots each, that is four slots.  You understand that each DMR repeater can support two simultaneous calls or conversations, correct?

That is why I used the term "conversation" as using slot or channel may get confusing.   

G

 

[intermod]

2 hours ago, WRXE944 said:

 

8 x 4 = 32

8 GMRS repeater channels X 4 slots/channel = 32.  

Each DMR repeater can support two slots or conversations, right?   It is four slots because *two* DMR repeaters can be placed within one GMRS channel, if you operate one higher and one lower in frequency.   Thus, 32. 

But maybe you were just showing where I said four. 

[SteveShannon]

21 minutes ago, intermod said:

And this is true.  Each slot can carry an independent and simultaneous conversation.  If I have 2 DMR signals or carriers, 2 slots each, that is four slots.  You understand that each DMR repeater can support two simultaneous calls or conversations, correct?

That is why I used the term "conversation" as using slot or channel may get confusing.   

G

 

Yes, I understand TDMA and time slots. 
My disagreement is that the current allocation of channels doesn’t support frequency division. 
 

[Guest]

@intermod - can you please answer me one question (below)...

I have been stepping away from this conversation as I do not think that this is going anywhere.

There is a lot of talk of making GMRS more efficient, about who hass the numbers right or wrong, and who might (or might not) like one or the other technology -- a lot of IFs and personal preferences and hypothetical math.

Here is my question:

What is YOUR purpose of GMRS ?!? - Why and how are you using GMRS ?

Maybe our needs for GMRS are different and we are just not aiming at the same goal ... ?!?

 

[intermod]

Just now, Sshannon said:

Yes, I understand TDMA and time slots. 
My disagreement is that the current allocation of channels doesn’t support frequency division. 
 

We agree on that.  Since emission designators need to be added anyway, the FCC just needs to add one or two new sentences in the rules to allow for that.

This current restriction you noted is: 

"§ 95.1765 GMRS frequency accuracy.

(b) The carrier frequency of each GMRS transmitter transmitting an emission with an occupied bandwidth of 12.5 kHz or less must remain within 2.5 ppm of the channel center frequencies listed in § 95.1763 under normal operating conditions."

Small problem. 

G  

 

 

[intermod]

9 minutes ago, WRXD372 said:

@intermod - can you please answer me one question (below)...

I have been stepping away from this conversation as I do not think that this is going anywhere.

There is a lot of talk of making GMRS more efficient, about who hass the numbers right or wrong, and who might (or might not) like one or the other technology -- a lot of IFs and personal preferences and hypothetical math.

Here is my question:

What is YOUR purpose of GMRS ?!? - Why and how are you using GMRS ?

Maybe our needs for GMRS are different and we are just not aiming at the same goal ... ?!?

 

One example from one of our repeaters.  Three different groups wanted to use one repeater (a general group, a family ranch & CERT).  Using analog, we gave each group their own CTCSS code so they would not hear the other group.  This was really needed as many were turning their volume down or radio off to silence the chatter from the other groups when they shared a single CTCSS code.  

But often enough they needed the repeater at the same time (weekends were the worst) and as expected, started walking on each other.   Training on using the monitor function or watching their busy lamp was attempted, but as always, this failed.  Using busy-channel-lockout (BCLO) was not possible as many radios did not have this feature, and the ones that did were locked out often due to traffic from commercial users and/or interference.   They all wanted to buy a different model radio..so we could not dictate this. 

Repeater site rent is expensive, so each could not afford their own repeater.  And, it would have required 3 of the 8 GMRS repeater channels for each to have their own.   But only one GMRS channel was available (our existing one) - the other 7 are used nearby.

With the proposed approach, each group could be assigned their own private slot and use it at the same time (with one slot left over).  Thus, placing two DMR repeaters in the space of one analog repeater would solve this problem, without using more GMRS channels.  And we would have one slot unused for yet another group.  Or maybe we dedicated that that for text-messaging or private calls. 

[intermod]

47 minutes ago, WRXD372 said:

@intermod - can you please answer me one question (below)...

I have been stepping away from this conversation as I do not think that this is going anywhere.

There is a lot of talk of making GMRS more efficient, about who hass the numbers right or wrong, and who might (or might not) like one or the other technology -- a lot of IFs and personal preferences and hypothetical math.

Here is my question:

What is YOUR purpose of GMRS ?!? - Why and how are you using GMRS ?

Maybe our needs for GMRS are different and we are just not aiming at the same goal ... ?!?

 

Here is another reason for placing two DMR repeaters within the same channel:

We have two repeaters, 20 miles from each other, on the same frequency (using different CTCSS codes).  There is significant overlap, so they cannot be used at the same time. 

We could use them at the same time if we replaced the two the analog repeaters with two DMR models, with one was moved down in frequency, and the other up in frequency.  So they would effectively be operating on two different channels and not interfere with each other.  

[Guest]

It seems that you are in a very specific situation and I understand your need for "more communication channel opportunities".

The way this sounds to me, your proposal will ultimately just be a band-aid but not a long-term solution too much need for radio communication and a very limited (GMRS) spectrum segment...

I still think that a more advanced technology is not the best idea for emergency communication such as CERT. Analog signals are easy to capture by any cheap scanner. With more potential listeners, the chance of getting help is larger than it would be on a digitally coded mode.

The only conclusion that seems reasonable is that densely populated areas are easily outgrowing the capabilities of GMRS.

If you ever travel to my area, you can tune in and enjoy silence on repeater outputs for hours 

[SteveShannon]

23 minutes ago, intermod said:

Here is another reason for placing two DMR repeaters within the same channel:

We have two repeaters, 20 miles from each other, on the same frequency (using different CTCSS codes).  There is significant overlap, so they cannot be used at the same time. 

We could use them at the same time if we replaced the two the analog repeaters with two DMR models, with one was moved down in frequency, and the other up in frequency.  So they would effectively be operating on two different channels and not interfere with each other.  

The main problem is that none of the current GMRS radios are compatible with those changes. 

[gortex2]

Another issue your are not thinking about is filtering for the repeaters. Taking a single 25khz channel and breaking it into 2 12.5 khz channels is not going to work. 

And if we are worried about frequency efficiency then set your radio for 12.5 instead of 25khz. GMRS could go to narrow band like LMR did. 

[WRQI583]

15 hours ago, Lscott said:

 

While people mention DMR IMHO that isn’t the best mode. In a prior post in this thread I posted an attachment PDF going into some detail on where and how digital voice could be added without a major disruption to existing FM operations. I would encourage you to read it. Particularly the last few paragraphs and links.

If the digital was kept to those channels, then yes, that would be the least impact, provided you don't sit in a busy area where every business and school is using all the channels. I'm not sure how other areas are. Some places are more busy with the bubble pack radios than others. NXDN looks like it would be a likely candidate with the low bandwidth.

I just hate to see anyone get negatively impacted, that's all. I happen to live in an area where they add one repeater after another, and no matter how many repeaters they add, none of them work for me when it comes to base/mobile comms. Either the base can hit the repeater and the mobile cant, or the mobile can hit the repeater and the base cant, or neither of them can, so I am limited to using simplex on one of the 8 channels, but I have to pick one that will have the least impact on all of the other GMRS users who are lucky enough to be able to float all over the state and have their base and mobile both be able to get into most or at least some of the repeaters. I just happen to be that guy who only has analog equipment and has to use simplex and that is how I invested because GMRS is analog.

But that PDF is very informative. Thanks for posting that.

[Lscott]

1 hour ago, WRQI583 said:

If the digital was kept to those channels, then yes, that would be the least impact, provided you don't sit in a busy area where every business and school is using all the channels. I'm not sure how other areas are. Some places are more busy with the bubble pack radios than others. NXDN looks like it would be a likely candidate with the low bandwidth.

I just hate to see anyone get negatively impacted, that's all. I happen to live in an area where they add one repeater after another, and no matter how many repeaters they add, none of them work for me when it comes to base/mobile comms. Either the base can hit the repeater and the mobile cant, or the mobile can hit the repeater and the base cant, or neither of them can, so I am limited to using simplex on one of the 8 channels, but I have to pick one that will have the least impact on all of the other GMRS users who are lucky enough to be able to float all over the state and have their base and mobile both be able to get into most or at least some of the repeaters. I just happen to be that guy who only has analog equipment and has to use simplex and that is how I invested because GMRS is analog.

But that PDF is very informative. Thanks for posting that.

I had thought about the impact on FRS by using those channels. IMHO as GMRS users we pay a licensing fee to use the spectrum. In my view that should give GMRS users priority over FRS users who get to use the spectrum for free. 
 

If FRS users also want the perk, well they can pay the fee and buy the appropriate radio.

[intermod]

18 hours ago, gortex2 said:

Another issue your are not thinking about is filtering for the repeaters. Taking a single 25khz channel and breaking it into 2 12.5 khz channels is not going to work. 

And if we are worried about frequency efficiency then set your radio for 12.5 instead of 25khz. GMRS could go to narrow band like LMR did. 

Works great.  Its been done since 1995.    You can place two repeaters 12.5 kHz (or 10 kHz) apart on the same antenna and duplexer by using a hybrid-type combiner.  Receivers can use an amplifier and two-way splitter.   

12.5 kHz narrowband is less efficient unless you use the freed-up spectrum on either side of the narrow signal, right?  And you can't place two 12.5 kHz analog narrowband signals on a GMRS channel due to overlap.

In fact, analog narrowband is an even a worse loss because it reduces your coverage (same affect as reducing your transmit power by half) and worsens interference susceptibility by 6 dB.  This is one reason digital was created (other than to sell more hardware...).  

[intermod]

5 hours ago, Lscott said:

I had thought about the impact on FRS by using those channels. IMHO as GMRS users we pay a licensing fee to use the spectrum. In my view that should give GMRS users priority over FRS users who get to use the spectrum for free. 
 

If FRS users also want the perk, well they can pay the fee and buy the appropriate radio.

Agree - it really has to work this way.