Say Goodbye to Your CB Radio
- Thread starter MidlandUSA
- Start date
DaveInDenver
Middle Income Semi-Redneck
The FCC and manufacturers anticipated this so GMRS is allocated 8 repeaters pairs. All of them are +5 MHz splits, so the repeater output is 462.xxxx based on the input. They would be shared use with the common simplex. So if your GMRS radio is capable of using repeaters when you set it to channel "550" it knows you mean use the repeater rather than simplex channel "15" (if you're using a Motorola GMRS radio) sharing 462.5500.
Therefore the inputs are:
467.5500 MHz
467.5750 MHz
467.6000 MHz
467.6250 MHz
467.6500 MHz
467.6750 MHz
467.7000 MHz
467.7250 MHz
A member of the Rising Sun required assistance about a month ago, got caught off guard while hunting I believe. He called for help on the Colorado Connection and a member of the Colorado Emergency Reporting Net heard and coordinated the recovery. Without these repeaters and hams our member would have faced a sizable walk just to find a dirt road and then he's still be faced with finding help in a remote part of Garfield County.
CO4x4RnR utilize the Colorado Connection for much of their communication because it's a state-wide linked repeater system that covers a great deal of the state and doesn't rely on cell service or any additional infrastructure. The whole system is self contained RF-links. It was previously UHF backbone but it has been largely moved to piggyback the Rocky Mountain Ham IP microwave network that supports their regional DMR network.
http://colcon.org
https://www.rmham.org
You may not see value in ham radio in your emergency planning but it still has plenty of relevance. But it's not fire and forget, the ham has to put in effort to use it. There are many options for more hand's off, SPOTs and InReach, cell and sat phones. Just different strokes.
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prerunner1982
Adventurer
It's not that it can't be done physically, it's that it's against FCC rules for both CB and GMRS since they do not use the same set of frequencies. However the FCC is also no longer certifying dual FRS/GMRS radios even though they share the same frequencies.
CB
"§95.987 CBRS additional requirements.
Each CBRS transmitter type must be designed to satisfy all of the additional requirements in this section.
(a) Transmit frequency capability. Each CBRS transmitter type must be designed to transmit only on one or more of the channels listed in §95.963. No CBRS transmitter type will be certified for use in the CBRS service if it is capable of transmitting on any frequency or channel other than those listed in §95.963, unless such transmitter type is also certified for use in another radio service for which the frequency capability is authorized and for which FCC certification is also required...."
GMRS:
§95.1761 GMRS transmitter certification.
(c) No GMRS transmitter will be certified for use in the GMRS if it is equipped with a frequency capability not listed in §95.1763, unless such transmitter is also certified for use in another radio service for which the frequency is authorized and for which certification is also required.
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camp4x4
Adventurer
GMRS already has designated repeater frequencies and setting them up is actually pretty simple. You turn to a repeater channel (15-22), enable the repeater function in the menu and off you go. It can be much easier than programming ham repeater frequencies because the pairs are pre-set within the radio. Now, some folks will program a GMRS repeater with weird splits and keep the PL tones private, but that's a slightly different situation.
As a ham I actually have used repeaters a number of times when out on trips. Most often when meeting up with people in areas of poor cell coverage.
camp4x4
Adventurer
Don't start in with the "real overlanders" nonsense.
You feel the need to point out that GMRS is primarily a USA service that's fine, but keep the gatekeeping to yourself.
Red90
Adventurer
You provide your opinions and I will provide mine.
camp4x4
Adventurer
Always good to know who to ignore.
dreadlocks
Well-known member
I run a GMRS repeater in my camper, solves a few range issues with GMRS.. for example, early last year I got sick at a camp.. I had a radio, wife had a radio.. I called her for help (need more TP) and because I was in a vault toilet and wife was in the aluminum camper they didnt work even though it was just a few hundred feet, wife just heard static.. Put the repeater on the camper and the next time we visited that site I tested it and the same radios worked perfectly fine at a greater distance.
Wife/Sons went on a hike down the valley scoping fishing spots, had em doing radio checks along the way.. when they got the furthest away before turning back I had em switch to simplex.. and got nothing.
even though my repeater is a ramshackle ham shack contraption, it works quite well.. an off the shelf solution would get my money.
Wife/Sons went on a hike down the valley scoping fishing spots, had em doing radio checks along the way.. when they got the furthest away before turning back I had em switch to simplex.. and got nothing.
even though my repeater is a ramshackle ham shack contraption, it works quite well.. an off the shelf solution would get my money.
Martinjmpr
Wiffleball Batter
WRT a combination CB/GMRS, I'll concede that if the FCC is not type-accepting any more CB radios then this is a dead end. IMO that's going to slow the adoption of GMRS because until a larger percentage of off-roaders in the US start adopting GMRS, users are going to have to run multiple radios. I guess it might be more of an issue if anybody wanted the 11m spectrum currently occupied by CB but it seems like all the "action" in the comms world these days is in the VHF/UHF bands.
WRT repeaters, currently most Ham repeaters are located on high elevation points and operated by local Ham clubs using their money for power and maintenance.
So who pays for GMRS repeaters to be purchased, installed and maintained? I could see in very popular locations with lots of off roaders you might be able to get a few of the local 4x4 clubs to donate money and/or time to operate the repeater, but elsewhere?
WRT repeaters, currently most Ham repeaters are located on high elevation points and operated by local Ham clubs using their money for power and maintenance.
So who pays for GMRS repeaters to be purchased, installed and maintained? I could see in very popular locations with lots of off roaders you might be able to get a few of the local 4x4 clubs to donate money and/or time to operate the repeater, but elsewhere?
dreadlocks
Well-known member
currently all repeaters are repurposed commercial gear, which is technically not kosher for GMRS use... its a chicken and egg thing; this site tries to track em: https://mygmrs.com/
day to day expenses of operating a repeater is minimal, but honestly.. I keep my repeater private for my party, if I had ever heard someone once provide their GMRS call sign OTA I might be more inclined to open it to the public.. but since I think most of the time I'm the only license holder in the area, I keep it for my self and dont feel bad for stomping on anyone else with my 45W of xmit.
Lets just get the legal hardware first, without that any dreams of a repeater network like the HAM's use is just a waste of time.. having a private portable basecamp repeater is a good enough use case to get it off the ground, some areas like MOAB where a public, fixed, wide area repeater could be justified will figure it out if the need exists..
day to day expenses of operating a repeater is minimal, but honestly.. I keep my repeater private for my party, if I had ever heard someone once provide their GMRS call sign OTA I might be more inclined to open it to the public.. but since I think most of the time I'm the only license holder in the area, I keep it for my self and dont feel bad for stomping on anyone else with my 45W of xmit.
Lets just get the legal hardware first, without that any dreams of a repeater network like the HAM's use is just a waste of time.. having a private portable basecamp repeater is a good enough use case to get it off the ground, some areas like MOAB where a public, fixed, wide area repeater could be justified will figure it out if the need exists..
Martinjmpr
Wiffleball Batter
I could see that. Bunch of 4x4 clubs could get together and pitch in on operating costs and put the repeater on a hilltop (maybe co-located with a Ham repeater or cell tower) for people to use in the area. They could solicit donations from users and/or tack on "communications support fees" when scheduling big events like the EJS, Cruise Moab, GONE Moab, and even the mountain bike support people would likely find it useful.
camp4x4
Adventurer
The FCC has admitted that they're aware lots of people are using part 90 gear on GMRS and they don't seem to have a huge problem with it since they're very similar in operation. It isn't ideal, but the part 90 stuff does seem to work just fine and no one seems to have issue with it. But I agree that legit off-the-shelf GMRS gear would be great; plug and play even better. Thing is, Midlands MXT400 is 95% of the way there. The only thing they need to do is create a "Repeater Receiver" mode where by the receive frequency is set to the 467.*** repeater input frequency (backwards from how their repeater mode functions right now, where the radio is Tx on 467 and Rx on 462). The unit already has internal pinouts that can be connected to a DB9 connector, for which there's already an opening in the back of the unit, and then to a controller. The rest is self-explanatory from there.
Right now I'm working on building a repeater using the Luiton LT-580, that Midland's MXT400 is based on, as a receiver, and an MXT400 as the transmitter. This will be 100% GMRS compliant since the transmitter is part 95 certified. I just ordered a Hamtronix ELEKTRA 2000VZ repeater controller with an auto IDer. An appropriate cavity duplexer from Amazon for $80 and various adapters, cables, etc... I think all totaled it'll be about $800 with everything. It won't be quite as robust as a purpose built repeater, but it is partially an experiment in doing it legit vs the known Part 90 gear route.
I think this is ultimately the most likely people to do it. Rubicon Trail Foundation has put up ham radio repeaters so the 'Con has ham coverage from end to end and then some. Seems a no brainer that a group could work with them to add GMRS equipment. I can think of a few mountain bike trails around Santa Cruz that could benefit from some radio coverage (due to lack of cell coverage) and some advocacy groups that could probably make it happen...
But, like dreadlocks said, we need some legal, and ideally truly plug-and-play gear first... Midlands, you listening?
dreadlocks
Well-known member
its a bit more complicated than swapping repeater input/output channels, need full duplex and they are operating in half-duplex (ie, not rx when tx).. but since all the repeater channels are defined by FCC putting a pre-tuned duplexer in the chassis would get the job done and help with less connectors/losses... make it a base station model that operates off DC w/a fixed mount option.. will save costs because RX frontend dont need TX capability and vice versa as opposed to two full fledged transceivers, put some good multipath filtering on RX and make it decently sensitive to give handhelds every bit you can.. probably needs vox ID because FRS/GMRS users will ****** if they hear morse (trust me I know heh).. also please good power output management to be battery and density friendly.
the biggest burden of deploying these for performance is the antenna (commercial collinear dipole array) and potentially the tower/grounding and power/solar or co-location fees, but ham's finance their own all the time and I wouldn't be surprised if many decide to spin up a GMRS repeater on emergency calling channels for various altruistic reasons they do now for HAM.. the problem is right now those guys with those big ass backyard towers they sunk a retirement into are never going to hookup anything not 100% kosher w/FCC, not with the the kinda money they got into it on the line... nor would any commercial site permit any of that, and they definitely wont want any home-brew setup even if it were technically legal.
@camp4x4 I'll be interested in seeing how your legit setup performs, you got a post about it I missed? I built my repeater over a decade ago, im so glad decent mobile radios are finally coming out.. its been a wasteland, im glad to see anything.
the biggest burden of deploying these for performance is the antenna (commercial collinear dipole array) and potentially the tower/grounding and power/solar or co-location fees, but ham's finance their own all the time and I wouldn't be surprised if many decide to spin up a GMRS repeater on emergency calling channels for various altruistic reasons they do now for HAM.. the problem is right now those guys with those big ass backyard towers they sunk a retirement into are never going to hookup anything not 100% kosher w/FCC, not with the the kinda money they got into it on the line... nor would any commercial site permit any of that, and they definitely wont want any home-brew setup even if it were technically legal.
@camp4x4 I'll be interested in seeing how your legit setup performs, you got a post about it I missed? I built my repeater over a decade ago, im so glad decent mobile radios are finally coming out.. its been a wasteland, im glad to see anything.
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camp4x4
Adventurer
Oh, I think you misunderstand: I have 2 radios, and my comment about swapping in/out channels is based on that concept.
But you're right overall that a dedicated box that did full duplex would be cheaper/better than using only half of each radio at 2x the price.
No post yet. Wanna actually get it working before posting anything.