Digital voice on GMRS

[RFI-EMI-GUY]

My point is that FM capture occurs on the highest amplitude RF signal peak within the channel. When the RF energy is fairly evenly distributed throughout the channel, more total RF energy is required to present the highest amplitude RF signal peak than if it is concentrated on a single frequency in the form of an unmodulated carrier.

Therefore, an unmodulated carrier is the most effective form of co-channel interference, but is less likely to cause adjacent channel interference.

A DMR signal is a full power, instantaneous unmodulated carrier EVERY 1/4800 of the time domain.

 

[12dbsinad]

On AM, yes. On FM, not so much.

On FM as well. This is why systems with already interfering adjacent channel issues from an analog system becomes totally crippled for a switch to digital by the offending party. Plus, it's transmitting more. More features, beacons etc

 

[SQP]

I see you guys have gone TECHNICAL!!! I'm still talking...PRACTICAL. As I scan the 8...ONLY EIGHT rptr frequencies of GMRS, I do NOT want to hear that digital trash in my analog receiver as I'm searching for and confirming new repeaters across the country. As I said earlier, the useless simplex traffic from...OTHERS, is more than enough!!!!!!!! If you really want to understand the CHAOS that digital will bring to GMRS, just search between 440 to 450 in a METRO AREA, and then, maybe you'll get the picture!! It's time to let sleeping dogs lie!!!!!!

 

[12dbsinad]

I see you guys have gone TECHNICAL!!! I'm still talking...PRACTICAL. As I scan the 8...ONLY EIGHT rptr frequencies of GMRS, I do NOT want to hear that digital trash in my analog receiver as I'm searching for and confirming new repeaters across the country. As I said earlier, the useless simplex traffic from...OTHERS, is more than enough!!!!!!!! If you really want to understand the CHAOS that digital will bring to GMRS, just search between 440 to 450 in a METRO AREA, and then, maybe you'll get the picture!! It's time to let sleeping dogs lie!!!!!!

You wouldn't have to worry about the "travel tone" anymore that's for sure.

What I want to know is, who dictates what type of digital would be used, The FCC? TDMA? FDMA? It would be the only band really that would force a user to a certain type of digital. Unless that plan would be a free-for-all of all mixed use. None of which is a good idea IMHO for non coordinated repeaters. That's why I'm a firm believer that the FCC will dump GMRS repeaters in favor of digital, let the cat's and dog's play on simplex like other countries and not worry about major interference.

 

[jonwienke]

A DMR signal is a full power, instantaneous unmodulated carrier EVERY 1/4800 of the time domain.

Actually, no, because the act of moving the carrier from one state to another creates additional frequency components in the modulated signal proportional to the slew rate at which the carrier moves from one FSK state to the next. Those additional harmonic components are what limit the maximum data rate--increasing the data rate or the maximum frequency modulated into the carrier increases the bandwidth of the modulated signal (Carson's rule). That's why the plots you posted aren't 4 discrete spikes; the additional harmonics needed to move the carrier from point A to B to C to D take up some of the energy that would otherwise end up in the 4 spikes, and fill in what would otherwise be gaps between them.

 

[SQP]

What I want to know is, who dictates what type of digital would be used

I DID ASK EARLIER!!!!!!!!

That's why I'm a firm believer that the FCC will dump GMRS repeaters in favor of digital

Can't speak on that, but I hope not. That's why it SHOULD be left alone.

 

[RFI-EMI-GUY]

I see you guys have gone TECHNICAL!!! I'm still talking...PRACTICAL. As I scan the 8...ONLY EIGHT rptr frequencies of GMRS, I do NOT want to hear that digital trash in my analog receiver as I'm searching for and confirming new repeaters across the country. As I said earlier, the useless simplex traffic from...OTHERS, is more than enough!!!!!!!! If you really want to understand the CHAOS that digital will bring to GMRS, just search between 440 to 450 in a METRO AREA, and then, maybe you'll get the picture!! It's time to let sleeping dogs lie!!!!!!

I agree 100%

 

[RFI-EMI-GUY]

You wouldn't have to worry about the "travel tone" anymore that's for sure.

What I want to know is, who dictates what type of digital would be used, The FCC? TDMA? FDMA? It would be the only band really that would force a user to a certain type of digital. Unless that plan would be a free-for-all of all mixed use. None of which is a good idea IMHO for non coordinated repeaters. That's why I'm a firm believer that the FCC will dump GMRS repeaters in favor of digital, let the cat's and dog's play on simplex like other countries and not worry about major interference.

That almost happened in 2017. The manufacturers selling the bubble packs don't like high power radios, repeaters or licenses and it was an uphill battle to convince the FCC that GMRS was a viable and valuable service. A big part of it remaining was the performance and interoperability it provided users.

The place for this "digital service' is the 900 MHz ISM band. Where it can be fully developed without any regulatory changes.

There are a lot of "ex" GMRS proponents who swear by the DTR radios and the range they provide. What is missing are repeaters and linking. /\/\otorola has a stranglehold on two way product, however Retevis, enGenius have 900 MHz ISM products and perhaps Maxon or Hytera could develop something .

 

[prcguy]

What does scanning the GMRS band with a receiver have to do with people who want to talk on GMRS in digital? That's no different than petitioning your local police not to go digital because you have an analog only police scanner. Do you think they care about that?

I agree 100%

 

[RFI-EMI-GUY]

Actually, no, because the act of moving the carrier from one state to another creates additional frequency components in the modulated signal proportional to the slew rate at which the carrier moves from one FSK state to the next. Those additional harmonic components are what limit the maximum data rate--increasing the data rate or the maximum frequency modulated into the carrier increases the bandwidth of the modulated signal (Carson's rule). That's why the plots you posted aren't 4 discrete spikes; the additional harmonics needed to move the carrier from point A to B to C to D take up some of the energy that would otherwise end up in the 4 spikes, and fill in what would otherwise be gaps between them.

As usual, you are getting lost in the "weeds". The plots are exactly what they are. I never suggested otherwise.

Face it, bringing a slew of digital standards into GMRS will wreck it. Nobody wants it. This reminds me of another thread proposing to eliminate repeaters, reduce power and narrow band the entire spectrum block.

 

[RFI-EMI-GUY]

What does scanning the GMRS band with a receiver have to do with people who want to talk on GMRS in digital? That's no different than petitioning your local police not to go digital because you have an analog only police scanner. Do you think they care about that?

I believe SQP was saying he travels and wants to find repeaters available for use as he travels (pipe in SQP if I got it wrong) . If in every major market many of those 8 repeater pairs are some odd flavor of DMR, P25 or NXDN , the prospects of interoperability are diminished.

 

[prcguy]

He can scan them in digital modes and log them just like any other service. Whether the digital repeater owner would allow others on the system for interoperability is a different subject. If and when GMRS goes digital I can see repeater owners posting info to myGMRS or similar sites stating the repeater is open or closed and access tones, NACs or whatever to use them.

I believe SQP was saying he travels and wants to find repeaters available for use as he travels (pipe in SQP if I got it wrong) . If in every major market many of those 8 repeater pairs are some odd flavor of DMR, P25 or NXDN , the prospects of interoperability are diminished.

 

[12dbsinad]

He can scan them in digital modes and log them just like any other service. Whether the digital repeater owner would allow others on the system for interoperability is a different subject. If and when GMRS goes digital I can see repeater owners posting info to myGMRS or similar sites stating the repeater is open or closed and access tones, NACs or whatever to use them.

Yes, he'll only need 5 different radios. What about Fusion and Dstar... I wanna play with those on GMRS too!

 

[RFI-EMI-GUY]

Yes, he'll only need 5 different radios. What about Fusion and Dstar... I wanna play with those on GMRS too!

You can be sure /\/\ will come up with Mo-Star and Midland will have My-Star . Uniden will have You-Star. BaoFeng will have Be A Star. None of it will talk together .

 

[SQP]

I believe SQP was saying he travels and wants to find repeaters available for use as he travels (pipe in SQP if I got it wrong)

YOU GOT IT!!!!!!!!!!!!!! As well as, now I have to buy...MORE RADIOS to accommodate this digital influx.

He can scan them in digital modes and log them just like any other service

Yes, my Uniden scanner'S will allow this, but is it...PRACTICAL?!?!?

Whether the digital repeater owner would allow others on the system for interoperability is a different subject.

YOU SAID IT, not me!!!! And let's not throw in...ENCRYPTION!!!

If and when GMRS goes digital I can see repeater owners posting info to myGMRS or similar sites stating the repeater is open or closed and access tones, NACs or whatever to use them.

Yeah, MORE RADIOS to buy.

 

[prcguy]

The only viable options right now are P25, DMR/MOTOTRBO and NXDN. There are no and probably never will be any part 90 Fusion or D-star radios. What digital can get you is plug and play mulit site connection across the state or across the country, if that's legal. A number of P25 and DMR/MOTO repeaters are designed for mulit site use.

Yes, he'll only need 5 different radios. What about Fusion and Dstar... I wanna play with those on GMRS too!

 

[RFI-EMI-GUY]

I look at GMRS as a tool like a hammer. It is simple and gets the job done. I am sure I can probably buy the shiny high tech digital equivalent of a hammer out there on the market but it wont be as good as the hammer I have. There is no convincing me that I need a digital hammer. But some spoil sport will convince the appropriate regulatory bodies that an analog hammer is dangerous and wasteful so my hammer will become outlawed to suit them. So my hammer will no longer work because common nails will be outlawed and I will be forced to choose between buying a crummy digital hammer or give up hammering altogether. This digital BS sounds like a commie plot.

 

[12dbsinad]

You can be sure /\/\ will come up with Mo-Star and Midland will have My-Star . Uniden will have You-Star. BaoFeng will have Be A Star. None of it will talk together .

Exactly. It kind of reminds me of what's happening with public safety in my area. We are going totally backwards, so far we have DMR, Mototurd trunked, NXDN trunked and P25 conventional all in a fairly small area. Now, agencies are *****ing because they can't talk to the other agency. So now on the fire side, the County is investing in a stupid plan vanilla analog voted simulcast system for mutual aid and interop.

Imagine that, ancient technology to save the day.

 

[RFI-EMI-GUY]

Exactly. It kind of reminds me of what's happening with public safety in my area. We are going totally backwards, so far we have DMR, Mototurd trunked, NXDN trunked and P25 conventional all in a fairly small area. Now, agencies are *****ing because they can't talk to the other agency. So now on the fire side, the County is investing in a stupid plan vanilla analog voted simulcast system for mutual aid and interop.

Imagine that, ancient technology to save the day.

Funny how it went full circle back to analog!

 

[prcguy]

Personally I've never had a need to use someone else's GMRS repeater. My digital radios also do analog so they are compatible with both modes if I wanted or needed to use someone else's repeater. Which I don't.

YOU GOT IT!!!!!!!!!!!!!! As well as, now I have to buy...MORE RADIOS to accommodate this digital influx.

Yes, my Uniden scanner'S will allow this, but is it...PRACTICAL?!?!?

YOU SAID IT, not me!!!! And let's not throw in...ENCRYPTION!!!

Yeah, MORE RADIOS to buy.