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Digital in GMRS - which mode is most appropriate?

digital nxdn p25 dpmr idas mototrbo dmr

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#41 intermod

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Posted 14 December 2019 - 01:13 AM

Fighting against change is the surest way to failure.

 

Well said.   

 

Digital will eventually happen.  The question is whether we (GMRS licensees) what to propose the rules, or let the manufacturer's propose the rules.   



#42 gman1971

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Posted 14 December 2019 - 02:31 AM

Well said.   

 

Digital will eventually happen.  The question is whether we (GMRS licensees) what to propose the rules, or let the manufacturer's propose the rules.   

 

Maybe it should be we, the users, who propose the rules. Manufacturers usually don't care about anything else but revenue... 

 

G.



#43 gman1971

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Posted 14 December 2019 - 02:47 AM

Yes, however, I suspect that a lot of the cheap radios used for GMRS are not even type accepted, and they put out spurious RFI emissions off the charts.

 

For example, I can hear my cheapie GD77ss like 1000 channels away when operating on DMR.... now you crank the power of that CCR with one of those CCPA  (cheap Chinese power amplifier) like the BTech one, up to 50W, and now you have spurious RFI crap and IMD all over the band. I have a similar situation (not caused by 50W CCR, but kilowatt TV stations and whatever crap is on the giant tower) and I am certainly not a happy camper... but I've taken extensive measures with cavities and LNAs to get the situation somewhat under control. While its not as good as a remote location with little RFI, or noise, but its certainly better than 3 miles on receive with a triple collinear 5/8 over 5/8, when I know that antenna was easily capable of 20+ before... 

 

Again, its also about using the proper equipment, and unfortunately for us, licensed operators, not everybody cares, and the CCRs, for all their virtues to help people get in the hobby, they also have a lot of downsides. Most new folks (like I did) just want the darn thing to work reliable as a cellphone, and when they can't reach 5 miles with 50W they immediately assume they need to run 500W, or more power until the dang thing works (or smokes). Radio range, as explained by marcspaz is not about more power, is about location, antenna and feedline + filtering.

 

 

G.

 

dPMR-like 6.25 might have been the approach if no other common digital mode existed.  But we have many now.  

 

You may have missed the earlier discussions here - interference has to do with signal level & proximity, not technology to any significant degree.  And the assumption that the number of users and interference sources would grow and cause overcrowding has no basis.  

 

In the end, changes in radio services and rules are always much simpler than you portray.  If the Commission simply permitted the typical digital emissions and made no change to analog operations or anything else - new digital radios would operate on existing channel centers.  Bandwidth is a don't-care.   And like today, if an analog direct-mode operation was interfered with, the victim would simply change channels until it went away.  Despite what the Commission believes, I have never seen one user call another and coordinate channel usage (FCC pipe-dream).  They can't - they are all in tone squelch, and if they could hear, they would just start spewing expletives at each other. 

 

Repeater operations would be the same as they are today - a new repeater owner would usually listen, select a channel, and work with the other co-channel repeater owners to arrive on a good (or least bad) channel.   In the beginning, most digital repeaters would be replacing existing analog repeaters - so the interference environment would remain unchanged.  Having the option to operate a digital repeater would not necessarily increase the total number of GMRS repeaters.  Digital repeaters are expensive enough that I cannot see many going up initially anyway.  User equipment is also slightly more expensive. 

 

What if a new digital repeater owner does not coordinate?  You listen for his (analog) Morse Code IDer, or buy the $90 digital radio with Promiscuous Mode and talk to them directly if you want to save time. 

 

Also - all the new digital equipment have an extremely good "busy-channel-lockout" features if it came down to it.   But like analog, nobody would want to use it. They would simply move their repeater to a different channel and avoid the headache (and likely jamming/self-policing). 

 

Would digital complicate the GMRS? Only for those who wanted to use digital.   If I don't want to understand it, then I could save money and just buy analog.      

 

Really - its just that simple. 



#44 Dbnakamoto

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Posted 28 May 2020 - 11:23 PM

Well said.   

 

Digital will eventually happen.  The question is whether we (GMRS licensees) what to propose the rules, or let the manufacturer's propose the rules.   

A few months late on this one...

 

GMRS was traditionally made out of used commercial equipment. So yeah it will happen, the question is, will it become the same non-interoperable mess that has happened in the ham bands. I think eventually it will become harder and harder to find analog repeater equipment. There is already many GMRS repeaters running XPRs in analog mode. So I really don’t think it will be long, especially when you can pick one up with a cheap duplexor for less than $1k. 
 

The only way it could possibly work is if one organization issues the radio ids, and operates the network (ONE SINGLE NETWORK), hopefully in tier 3. Otherwise I fear it would just be doomed to become the same fractured mess that digital modes are in ham radio. Even if the current standards don’t allow for it, whatever form it takes in the future would still need to adhere to the sprit of those regulations.



#45 Lscott

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Posted 29 May 2020 - 08:10 AM

 

The only way it could possibly work is if one organization issues the radio ids, and operates the network (ONE SINGLE NETWORK), hopefully in tier 3. Otherwise I fear it would just be doomed to become the same fractured mess that digital modes are in ham radio.

The mess on the Ham Bands is due to Hams trying out every digital mode out there. At least there is enough spectrum to allow that. If somebody is running digital either switch to a different repeater or spin the VFO knob to find an open frequency for analog.

 

On GMRS there is a VERY LIMITED number of channels available. Once you start mixing in analog and digital is where you'll see the real mess. People with an investment in analog radios are not going to trash them so the mix with be with us for a long time if digital is allowed. 

 

The solution is to change the rules to allow only digital on one or more channels where the balance is analog only. Adding in another one or more channels reserved for digital only wouldn't require existing users to reprogram their radios. However I doubt the FCC is going to add additional channels unless there is a huge demand and or the manufactures lobby for it. That's how we ended up with the FRS mess.

 

Don't forget for digital you will likely need at least one channel for digital simplex and another "frequency pair" for digital repeaters. Without additional channels that has to come out of the exiting 22 simplex ones now, which 8 also being used as repeater output frequencies, and the 8 exclusive repeater input frequencies. That's a big bite out of the current spectrum.

 

If a digital mode were to be selected DMR makes sense. Even one NB analog channel converted to digital can handle two digital voice channels. That would improve the spectrum efficiency so you may not need that many digital only channels. 

 

Allowing linked GMRS DMR repeaters? That's a whole other can of worms. You need a registration authority, a network of high level routers etc. Just look at the Ham Bands to see the work required to setup and maintain a digital network. With GMRS being primarily for personal and family communications you need to find some very dedicated people to do the work, know what they are doing and have the money. As it is now there don't seem to be even that many linked analog systems on GMRS. Now you want to add in digital?

 

Last thing, somebody will get the "bright idea" to link a GMRS DMR repeater into other services or outside of the US. Remember GMRS is prohibited from communicating with stations outside of the US or other services. People have setup illegal cross-band analog repeaters between GMRS/FRS and typically MURS so the idea that won't happen with digital isn't realistic. If digital is ever allowed the FCC could simply prohibit any linking of digital repeaters to discourage people from doing it.   



#46 deanq

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Posted 05 June 2020 - 10:07 AM

A few months late on this one...

The only way it could possibly work is if one organization issues the radio ids, and operates the network (ONE SINGLE NETWORK), hopefully in tier 3. Otherwise I fear it would just be doomed to become the same fractured mess that digital modes are in ham radio. Even if the current standards don’t allow for it, whatever form it takes in the future would still need to adhere to the sprit of those regulations.

 

I think you may have a conceptual misconception of digital and GMRS. This isn't ham radio, with international linking. No radio id issuing is required for a repeater to work. You can utilize id's but not required.

I do not foresee digital anytime soon for GMRS. The gears of government grind too slow. JMHO
 



#47 jlag

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Posted 08 June 2020 - 10:05 AM

I'll just point out that if anyone wants to do UHF DMR, the FCC already allows for that. It's called Part 90 Private Carrier (FB6 designation). Go get a 10-year license - get a Coordinated Frequency pair, and have at it. You no longer need to be concerned about getting Part 95 certified equipment, you don't need to worry about who qualifies as a "Family" member, and you can go ahead and "rent" airtime to anyone you want to, at any price you choose to. There's no requirement to charge a set amount or fee to anyone as a Private Carrier - you get to set your own rates (Zero if you wish), and you get to decide who uses your system.

 

 

 

Hello RadioGuy,

This is interesting.

 

1. Would FB6 be part of Part 90 "IG - Industrial/Business Pool - Private, Conventional" frequency pair?

2. Does this mean that I could get a DBA for my business such as "XYZ Comm", get a frequency pair and "rent" time to myself/family and friends for business and personal use?

3. I have a 60 foot mast at my residence currently, would it be allowed to run an FB6/IG transmitter at my residence (legal business address)?

4. Would I be subject to a site inspection prior to operation?



#48 Radioguy7268

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Posted 08 June 2020 - 01:00 PM

I think you've got the concept - run under Part 90 as an FB6/IG - but you need to certify that you're going to provide communications service to "Part 90 eligibles" - which means US Citizens and US Companies that would be otherwise eligible under Part 90. Technically - you could also provide FB6 Private Carrier service to Public Safety entities - or a non-profit Town Watch group.

 

I'm not the law, and I'm not the FCC, but I've done this type of licensing for other entities. You are the one who needs to certify what you are planning to do, but I'm not aware of any requirement to "show your books" to the FCC to prove that you're running a for-profit business, or any site inspections. You will need to run Part 90 type accepted equipment, and you will need to certify buildout/construction within 1 year of your License being granted by the FCC.

 

Judging by your GMRS license, you're located in a fairly populated area, so finding a decently clear frequency pair might be a bit of a challenge in the Part 90 spectrum. If you've already got a 60 foot mast, try to monitor some frequencies and see if you can identify any open frequency pairs in the area. Used to be that some of the older 451.8xxx pairs were clean, but most communications companies have snatched those up - at least in my area.

 

I'd try looking up someone like FIT (Forest Industries Telecommunications) or EWA (Enterprise Wireless Assocation). They'll walk you through the steps. I find FIT to be a little more personable - but EWA is very professional & capable. Up front cost isn't cheap to get the 10 year FB6 license & coordination - expect to see something around $700, but it's still pennies per day. If you tell them you're looking for an FB6 UHF repeater pair with DMR/Trbo emissions, you'll be off to the races.


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#49 BoxCar

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Posted 08 June 2020 - 02:17 PM

AASHTO or actually Radiosoft does both 90.20 and 90.35 in house. I used to oversee the 90.20 portion. www.radiosoft.com will let you see their price schedule for coordination and license filing.


Old and wise infers you were once young and stupid


#50 jlag

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Posted 08 June 2020 - 02:41 PM

I think you've got the concept - run under Part 90 as an FB6/IG - but you need to certify that you're going to provide communications service to "Part 90 eligibles" - which means US Citizens and US Companies that would be otherwise eligible under Part 90. Technically - you could also provide FB6 Private Carrier service to Public Safety entities - or a non-profit Town Watch group.

 

I'm not the law, and I'm not the FCC, but I've done this type of licensing for other entities. You are the one who needs to certify what you are planning to do, but I'm not aware of any requirement to "show your books" to the FCC to prove that you're running a for-profit business, or any site inspections. You will need to run Part 90 type accepted equipment, and you will need to certify buildout/construction within 1 year of your License being granted by the FCC.

 

Judging by your GMRS license, you're located in a fairly populated area, so finding a decently clear frequency pair might be a bit of a challenge in the Part 90 spectrum. If you've already got a 60 foot mast, try to monitor some frequencies and see if you can identify any open frequency pairs in the area. Used to be that some of the older 451.8xxx pairs were clean, but most communications companies have snatched those up - at least in my area.

 

I'd try looking up someone like FIT (Forest Industries Telecommunications) or EWA (Enterprise Wireless Assocation). They'll walk you through the steps. I find FIT to be a little more personable - but EWA is very professional & capable. Up front cost isn't cheap to get the 10 year FB6 license & coordination - expect to see something around $700, but it's still pennies per day. If you tell them you're looking for an FB6 UHF repeater pair with DMR/Trbo emissions, you'll be off to the races.

 

 

 

Thanks RG7268, Makes perfect sense.

It does seem that there are some 440 and 222's available for co-ordination. I certainly wouldn't want to grab a pair off a waiting list in a hot market if the frequencies would be idle 90% of the time, doesn't seem fair. Maybe its time to start a for-profit communication business, put a 100 footer up at my business site :) $700 is a great price considering what you are getting. Aligns with the cost of quality feed-line, antenna, duplexer, maintenance, time, time and more time. Still cheaper than a boat.



#51 Radioguy7268

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Posted 08 June 2020 - 03:50 PM

I'm not sure how close you are to Canada - but just wanted to make sure I'm clear. Business frequencies under Part 90 do not share any frequencies with amateur radio. Your comment about 440 and 222 makes me wonder if you checked availability with an amateur Frequency Coordinator. There is no "waiting list" in the Business bands for Part 90 UHF.



#52 jlag

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Posted 09 June 2020 - 12:10 PM

I'm not sure how close you are to Canada - but just wanted to make sure I'm clear. Business frequencies under Part 90 do not share any frequencies with amateur radio. Your comment about 440 and 222 makes me wonder if you checked availability with an amateur Frequency Coordinator. There is no "waiting list" in the Business bands for Part 90 UHF.

I had checked with NESMC. VHF is waitlisted, UHF is not, but getting tight.

But correct, I should have been looking at 450-470 frequencies I believe.



#53 Radioguy7268

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Posted 09 June 2020 - 01:39 PM

 

 

NESMC, the New England Spectrum Management Council, is the NFCC certified frequency coordination body for amateur operations on the 29MHz and up frequency bands in the states of Maine, New Hampshire, Massachusetts, and Rhode Island.

 

 

Again - Part 90 is NOT controlled by any of the amateur Frequency Coordinators. You're going to have to check with someone else. There are certain particulars that involve areas of operation that get within a certain distance of the Canadian borders. I'm not up in that area, so I've never really paid much attention to the Border rules. 



#54 jlag

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Posted 09 June 2020 - 02:38 PM

...I'd try looking up someone like FIT (Forest Industries Telecommunications) or EWA (Enterprise Wireless Assocation). They'll walk you through the steps. I find FIT to be a little more personable - but EWA is very professional & capable. Up front cost isn't cheap to get the 10 year FB6 license & coordination - expect to see something around $700, but it's still pennies per day. If you tell them you're looking for an FB6 UHF repeater pair with DMR/Trbo emissions, you'll be off to the races....

Yes, as you mentioned, for example, FIT (Forest Industries Telecommunications) or EWA (Enterprise Wireless Assocation).

​I am in eastern MA, a good bit south of the line.







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