Lscott

I did an FCC search on 462.5625 and 467.5625. I found only one listing, and the license was expired. It was not for a railroad. I have no idea why Radio Reference has this listed for a railroad unless it's an error in their database. https://wireless2.fcc.gov/UlsApp/UlsSearch/results.jsp https://wireless2.fcc.gov/UlsApp/UlsSearch/licenseFreqSum.jsp?licKey=1754132

My wild guess why this happens is due to the fact no license test is required, like Ham Radio where the above type of groups and activities are commonly found. Then, if some members are too cheap to even pay the $35 GMRS fee they try and use FRS radios. I agree with the points above with LMR radios. I'm, again guessing, that getting permission to use already licensed LMR frequencies by "affiliated" groups wouldn't be a big problem. I do not agree completely with GMRS "NOT to be relied on for life and death communications" in the event that local communication infrastructure is destroyed due to fire, floods etc. GMRS might be one of the very few ways the general public has available to maintain communications in a local area. In fact I think that was mentioned some time back in another thread.

Being TDMA with about a 50 percent duty cycle that works out to an average power of about 50 watts. Maybe that's how the FCC looked at it for the license grant.

No, but they do allow vanity calls like this for Hams. https://wireless2.fcc.gov/UlsApp/UlsSearch/license.jsp?licKey=806849 Note the Ham is a female too. You figure it out.

The first "miracle" required is just getting the FCC to allow digital voice modes on GMRS in the first place.

That's what some people have used for building a simple repeater using two separate radios. Best use of one is for a cross band repeater. Lets say between 2M and 70cm bands for Ham use. You can run two low power radios into one antenna using a duplexer. https://mfjenterprises.com/products/mfj-916b I believe you can get about 60db isolation between to two ports with the above model.

I seem to recall reading a few messages on other boards about problems with some repeaters not opening up due to the low volume of the access tone in narrow band mode.

I'm primarily a Kenwood guy but I do have several of the older Motorola XPR-6550 radios. https://forums.mygmrs.com/gallery/image/261-e451d5e2-f358-40dd-95a1-af106f7e8584jpeg/ Yes they can be programmed to work on GMRS. However I checked my documentation and non of the FCC certification grants show Part 95 on them so technically they are not legal to use. I have no idea if any Motorola commercial grade radios that will work on GMRS carry Part 95 certification. To start off with you should be looking for a radio that has it regardless of manufacture anyway. On the other hand a number of my Kenwood radios have Part 95A certification and are legal. The one I carry around lately is the TK-3170 Type-1. https://pdfs.kenwoodproducts.com/9/TK-2170&3170Brochure.pdf Another one that a few have as well is the TK-3180 Type-1. While the Type-2 will work only the Type-1 has Part 95A certification. https://pdfs.kenwoodproducts.com/10/TK-2180&3180Brochure.pdf I do have a collection of other radios some of which also have Part 95A certification. If you have questions about those I can help with that. https://forums.mygmrs.com/gallery/image/249-934916052_radiocollectionjpg/ Here's a couple of photos of the mid-tier radios I have. https://forums.mygmrs.com/gallery/image/254-tk-5320-1jpg/ https://forums.mygmrs.com/gallery/image/251-nx-300jpg/ This is a cool radio, will work on GMRS, BUT it doesn't have Part 95 certification, doesn't have an FCC ID either since it was never sold in the US! Bummer. Works great on the Ham bands for DMR and FM, which is why I got it. https://forums.mygmrs.com/gallery/image/255-tk-d300e-fmdmr/ https://forums.mygmrs.com/gallery/image/271-new-in-the-box-tk-d300e/

So in the case of that radio it does appear you can mix TX and RX frequencies so I off base on that one. I guess I should be more careful about making statements on radios I haven't really used. Thanks for pointing it out. In any case one can use that radio and try out the split frequency operation for fun.

VHF marine HT’s might be the way to go as long as they are used on the water. They are license free as far as I know. Many if not all will float if dropped into the water. Something a GMRS HT likely won’t do. Nothing worse than watching a $100+ radio sink out of sight.

You advocating the use of uncertified radios on GMRS? I'm not. Also this part I guess you missed, "the cheap frequency preprogrammed radios", does not apply to the UV5R type radio since it is freely frequency programmable. Radios such as the 805, 905, 935 and similar from other manufactures etc. have preprogrammed TX and RX frequencies you can't modify and are commonly used for GMRS.

It's also not Part 95 certified. I'm talking about radios certified to use on GMRS.

I would venture to say a number of people have operated in an illegal manner, modes, power etc. a few times or routinely. I would hope they know the rules and understand the consequences if the FCC notices. At least they are smart enough, most of them anyway, not to publicly advocate or mention what they are doing, it sets a bad example for the newbies.

If you wanted to keep someone from using your repeater with the cheap frequency preprogrammed radios then picking a non standard frequency split would do the trick. Since the rules don't require one to use a 5 MHz split you're free to pick from any of the 8 TX and any of the 8 RX frequencies for the repeater. The only radios that will work in that case are modified radios and commercial Part 95 certified radios which you can independently set the TX and RX frequencies. Also the same idea will work to frustrate simplex jammers. Radio one will TX on F1 and RX on F2. The other radio will TX on F2 and RX on F1. Both frequencies are legal simplex channels. Each user can have several channels programmed up with different combinations of TX and RX simplex frequencies and switch between them, memory channels, as conditions demand. To do this with more that two radios is not as simple and would likely require some method to scan several channels very rapidly, a programmable home or priority channel feature etc. As far as I can see there is nothing in the rules that prohibits this either. So long as your operation is not causing interference, as you pointed out, it should be OK.

People need to read the rules before believing some of the stuff they get on the 'net. The rules don't limit the number of repeaters, just the number of frequency pairs, GMRS "main channels", they can use, currently the rules list 8 RX and 8 TX frequencies. As a side note I don't see anything that requires the RX and TX frequencies to be exactly 5MHz apart either so long as you use one of the 8 TX and one of the RX ones listed in the rules. https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E/section-95.1763 You can have as many repeaters as you want on a frequency pair so long as the frequency is shared with other users.

https://www.youtube.com/watch?v=HNLQ-O-Qx3Y

By an inline attenuator. Put that on the output. I got this one used for about $50 a while back as an example. I also have a set of low power Weinschel's to use with an old HP power meter. Narda Fixed Attenuators.pdf Models 1 and 2.pdf HP432A Specifications.pdf

Try the attached files. Canada VHF LADD Channel List .pdf CB Radio Around The World.pdf Civil Air Patrol.pdf Common Itinerant and Business.pdf Freenet-2.pdf KDR444.pdf 1156812829_PMR446WhitePaper.pdf Railroad - Scanner Frequencies and Radio Frequency Reference.pdf VHF Marine Frequencies - 1.pdf

I looked it up since the official RR frequency list can be found in the attached file and the ones you listed didn't look like what I expected. Of course there could be additional ones assigned by the FCC for special uses. Got curious and had to check. I have a code plug written with all of the official VHF FM and NXDN digital railroad channels for a Kenwood NX-200 radio. The portable radios used mostly by the railroads are from Kenwood and Icom. https://comms.kenwood.com/common/pdf/download/02_NX-200G&300GBrochure.pdf I haven't really tried it yet. If anyone is interested I've attached a copy. It also has some of the Ham 2M simplex channels, MURS and the VHF NOAA weather frequencies too. With 512 available channels it wasn't much of a squeeze. Railroad - Scanner Frequencies and Radio Frequency Reference.pdf NX-200 Railroad 20220422.dat

Very unlikely. If one wants VHF access use MURS. Want HF access use 11M CB radio. Want more channels, power, repeaters and bands get a Ham license. That's going to be their logical response.

I did a search on the FCC site for the exact frequency of 151.625 just to see what pops up, a HUGE number of hits. Only a few look like they have anything to do with railroads. 2187 WREJ974 RAILROAD CONSTRUCTION CO OF SOUTH JERSEY, INC. 0028698892 IG Active 10/17/2029 2188 WRFR834 RAILSERVE INC 0028619906 IG Active 04/20/2030 2189 WQVF999 Railworks Track Systems 0024232860 IG Active 01/30/2025

Given the frequency split between the 151 MHz and 154 MHz frequencies that wouldn't be too hard. Of course it isn't legal.

Yes, they already have several modes in use under their license free PMR service. They have the narrow band FM, similar to our old FRS, the low power DMR and Digital PMR. The issue is getting the FCC onboard with doing any kind of digital voice mode on GMRS. They have been very resistant to the idea. 1021937093_PMR446WhitePaper.pdf

The hood location will compromise your range. The better place was on the roof. I had a roof rack mount on my old Jeep. The cable ran down the side of the rear hatch opening. I used some duck tape to hold the cable in place along the opening and then ran the cable through at the bottom with a “drip leg”. The hatch door covered up the tape so you can’t see it. That way any rain would run down the cable and not get through the hatch seal.

Interesting comment. I think those channels could be put to better use IMHO. In another thread there is a suggestion to use those interstitial channels for the addition of digital voice mode. Using a narrow enough digital signal overlap with the "official" 20KHz adjacent GMRS main channels could be reduce to less than the current 11KHz narrow FRS FM, or eliminated. There are some digital voice modes that only use 4KHz bandwidth and would fit in without overlapping the GMRS main channels. Might even run at much higher power too, like at least 5 watts, the limit for hand held GMRS radios.