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Very likely a screw-up by people who implemented algorithm for particular hardware. I was at this very place some 20 years ago, working on TEA implementation (not related to radio). Used uint instead of int in one place, and it caused a degradation of entropy. Luckily, my mistake was caught in time and never went into production.

To actually answer the question: On all radios manufactured since 2017 all GMRS and FRS channels are the same and all GMRS radios can talk with FRS radios and visa-versa. Most mobile GMRS radios may not have some of the channels (8-14) on them, but otherwise, if you put both radios on the same channel, you can talk. Narrowband and wideband radios can talk to each other - however you may notice some volume issues; many people do not notice at all. TL;dr: You can use your FRS radios and your MXT275 without any significant/real-world issues.

I would add to @Sshannon’s info that most GMRS radio (if not all) will have this +5 offset already added in the preprogrammed channels for repeaters. 21: TONE-SCAN] CTCSS/DCS Scanning Function: Scans the incoming signal for CTCSS or DCS tones to identify or confirm the correct tone. This function must be activated while receiving a signal. Options: 1. CTCSS/2. DCS Default: None. Choose the function and press [MENU] to activate the scan. Note: The scan will stop when the signal ends and resume from where it left off the next time the signal is received, until it identifies the correct tone. Use the [UP]/[DOWN] arrow keys to scan in a different direction

There never was. Advances in decryption algorithm design, number theory etc. soon renders many cryptographic techniques obsolete. The point of most encryption in the public arena is to foil the "casual" radio monitor. i.e. those with scanners, or scanning two way radios. Making the cost, in terms of time and hardware, significantly higher than the value of the intercepted communications deters most people from bothering to try. I have on order several ARC4 40 bit encryption licenses for my NX-1300 DMR radios. Is it secure? No, but should be good enough to lock out the "casual" monitor when used infrequently and the key switched on a frequent basis when it is used. Some of my other radios, the NXDN and P25 types, can use a special digital encryption module, which requires a special cable and external hardware key loader. Those modules are expensive. They also have to meet various tests for security. See attached file. There are also various types of analog scrambling modules too. I've attached a sample for a TK-3170 radio. Kenwood Secure Cryptographic Module.pdf Midian-TVS-2-KW2-VPU-15-KW2-Manual.pdf

I wonder if the frequency limits setting has anything to do with this?

Most likely that's just BS. Manufactures still stick crap like that on their products hoping some will believe it. https://consumer.ftc.gov/consumer-alerts/2022/07/ftc-says-companies-warranty-restrictions-were-illegal

The default offset is +5 MHz for GMRS. So, if your repeater is transmitting on 462.550 MHz you will transmit to the repeater at 467.550 MHz. As far as searching for tones, the feature is probably covered in your instructions. It will be called “scan for tones” if it is. But you must be scanning the transmit frequencies to be certain because the transmit tone is not always the same as the receive tone. It’s usually better to just ask for access and be given the tones.

Throw a GMRS/FRS party. Invite everyone in your neighborhood. Be ready with a show and tell session.

Thanks OffRoaderX for that valuable info. RE 1) Unfortunately, the strongest repeater available to me just happens to occupy Ch 15 on 462.550 making this a major problem for me RE 2) Yes, same behavior here... does not work in Channel mode, but does work in Frequency mode. But the unit does not transmit in Frequency mode... so what's the design logic of having a functioning Low/High power (#) toggle located there? RE 3) Downloaded and installed numerous USB/Serial port drivers that allegedly work with CHIRP on this unit... nada so far. Seller has offered to email me his programming software if I provide him with my email address (I'm hesitant to do that - call me suspicious). I already have the software on the CD-ROM that came with the cable I purchased from him, so that offer is a waste of time While trying to resolve this mess, I will purchase a few more on Amazon and will use your link as I really do enjoy your youtube videos... very informative. If this GMRS thing works out, I plan to install a repeater up here. My rural location is over 1,300' high with an unobstructed 180 degree 40+ mile view to north-east-south. RF energy up here is pretty amazing. I mention this as I know that you too also have a high elevation base... I assume that a repeater up here would really sizzle... yes?

Just as a side note: I did not use the FCC database so I could contact people regarding radio stuff, or anything else. That would be an unwelcome faux pas in most cases.

Feel free to reach out to me if there’s anything I can do to help.

No. Too many people want to reinvent the wheel so to speak.

Hey guys, WRXE944 = Since this is a portable intercom system I plan on using it with my Kenwood mounted in a noisy fire truck - hence the reason I purchased the intercom. I seriously doubt the FAA will have any issues with that. BoxCar = I purchased this entire used (looks & performs like new) system with two practically new headsets for under $150. I refuse to pay the outrages prices of the equipment from pretty much ANY U.S. based company. I'm all for making a profit but the mark-up that they place on their equipment is shameful. Sshannon = I am not very good at building anything related to communications equipment and I lost my good friend (in the amature radio world he would be referred to as an ELMER) last year. He was the only person (other than the awesome folks on this website) that I could go to for help/guidance and to be honest, I don't really enjoy building this sort of project BUT.......That's exactly what I am going to attempt. I've already purchased the PJ-055 & PJ-068 female panel mount connectors for the double plug lead of the intercom to plug into (instead of modifying the intercoms connections), a DB25 connector to plug into the radio's accessory port and just in case I need to use the front mic port, a RJ45 connector. Now it's just waiting for my orders to arrive and me, not having much of a clue as to what I am doing, trying to figure out what wire to connect to where and hope I don't short, burn up, blow up the radio and that my contraption will work properly. Only one way to find out. I'll post an update either way in a few weeks. Thanks for the suggestions everyone.

https://www.texasgmrs.net/ has almost every repeater in Texas.

Narrow band transmissions received on a wideband radio might sound weak (I’ve read) but the units are still capable of talking to each other.

Look up the licensee on the repeater page of this website or on the FCC license search page and write a letter. Every license is there.

I’m not clear on your question about replying so here’s the pedantic version: To reply while quoting the post you’re replying to, simply click on the word “quote”. To reply without quoting, just go to the bottom of the screen and type in your reply. In either case you then click “Submit Reply”

I think @back4more70 may be right on this. If not try downloading your wife’s settings in Chirp and then upload those to your radio. You can compare the two for every setting too.

Just received my GMRS-Pro a few days ago. The antenna does come off. That said, There is a notice that says you will void the warranty if you remove it.

GMRS radios, those certified under 95e, are GMRS Stations. In order to use a GMRS Station, you must be operating under the authority of a licensed user. In that instance you must comply with all of the rules in 95e, including those regarding identification (using your call sign) FRS radios, those certified under 95b, are FRS Stations. If you're using one you are required to comply with the rules of 95b. It's that simple. No license is require to use an FRS Station. The rules for 95b do not require identification. It doesn't matter if you have a GMRS license. When a GMRS station talks to an FRS station, the person operating the GMRS station is required to follow GMRS rules. The person operation the FRS station is required to follow FRS rules.

Did you look to see what GMRS repeaters are in your area? There are several in Colorado. That might lead to a GMRS club, which would be a pretty good way to find folks who are interested in talking to others about GMRS.

Well Kirk, since you insist in casting falsehoods and trying to tarnish my reputation, here's what actually happened You emailed me, vaguely explained the problem, and asked for help. I replied that afternoon (even though it was my daughter's birthday), suggested a few initial guesses as to what might be going on, and explained that while I don't officially support CHIRP, I would be happy to look at your IMG file and see if I could figure out what was going on. There was absolutely no "accusing" of anything or anyone. We hadn't even started to diagnose the issue yet. You emailed your CHIRP images about 27 hours later. You emailed the store about 24 hours later trying to do an end-run on me by claiming that I was unresponsive, and asking how to return the radio, claiming that the radio was buggy. I replied 16 minutes later to reiterate that I was happy to try and help you solve the problem, and that CHIRP works fine with the PX, but that it sometimes requires a little patience on some systems, but that I wasn't aware of anyone that couldn't get it running. I also explained that I would look at your files on the weekend, as I was backed up on support issues, so you knew when to expect a response. You replied 2 hours later and said you just wanted to send it back for a refund because "there is so thing flaky with it [the radio]." I replied 2 hours later (after hours) and reiterated again that nobody that I know of hasn't been able to get the PX working with CHIRP, in case you wanted to change your mind overnight, but that I would generate your RMA return in the morning. I also informed you at that time that because you were refusing to troubleshoot the radio with me, that the return would be subject to my 30-day return policy, which will include a restocking fee. It was not a threat, it was a preview of the return terms I would have sent you with the RMA # in the morning, in case you wanted to take your chance with actually keeping the radio (since I know it was most likely not a faulty radio). You replied early the next morning and told me that you already tried and did everything right, and that your UV9GX worked, so you just wanted to return the radio instead of "going through any more hassles." You emailed yet again and gave me more reasons why you were right (keep in mind that we hadn't started any troubleshooting yet), and said you shouldn't have to pay any restocking fee or even the return shipping fee, even though you refused to do any troubleshooting with me, and that you would be sure to share your experience "on the forums," obviously as a veiled threat to do exactly what you're attempting to do here by distorting reality. You then told me about how another dealer sent you a new radio to replace a bad one. Funny, that's what I do when someone gets a bad radio also. You didn't. Finally, you emailed me a few hours later and said you solved the problem with the help of the nice people here in this forum, and not to bother with the return. I promptly filed away your email messages, unsubscribed you from email list, and blocked you from my site. There was no arguing from my side - it was mostly just you telling me how right you were, and being impatient, and then discovering all your assumptions were wrong all along, and then blaming me for everything unfair in the world. I rest my case, but thanks for the grade, teacher.

Good explanation Corey. Its also important to note that even repeaters have some form of duty cycle and that the duty cycle can change depending on output power. A great example is the motorola 1225 series repeater. At full power, 45 watts, the repeater is limited to a 50% duty cycle. In low power, 25 watts, they are 100% cycle. Luckily, good repeaters have protection in the form of a Time Out Timer (TOT) and usually a ReSet Timer (RST) When set up correctly, the TOT should cut off the TX BEFORE the duty cycle is reached, and the RST should prevent transmissions until the appropriate rest period has passed. This helps extend the life of the repeater even when your not there to monitor it. Almost ALL radios now-a-days have a TOT as well. Typically I set mine for 2 minutes which is more than I need to transmit for, but is less than the duty cycle permits thus protecting the transistors. I've had people tell me its dumb to do as no idiot would want to talk non-stop unless they are in a net or special operation. That's when I give them this story: A while back when I was on the first aid squad, I was getting ready to go to sleep. Turned out the lights, laid my head on the pillow, then came the sound of a soft moan from a woman. Now, this would have been great, if there had been a woman in bed with me. The moaning continued and a bit confused I began looking for the source. Didn't take long to find my squad radio was receiving, and after turning it up a little, yep you guessed it. Turns out, the LT's portable radio had fallen between the bed and the night stand and as they and their lover were going at it, it was all transmitted quite clearly to the repeater, then retransmitted for the ENTIRE COUNTY to listen to. To make matters worse, the radios all had ID numbers so we knew whos radio was transmitting, and even worse, the LT had shut their phone off, so calling them to tell them their private session was public was not doable. Finally, the radios did not have TOT's at the time and so for a good while (I just shut my radio off but a friend at the county said they heard every minute of the 15+ minute incident. When the portable finally cut out, either from overheating or a dead battery or from falling loose of the PTT button, there wee quite a few catcalls to let them know everything was public including a few repeats of nick-names used during the session. So folks, learn two things from this story. A: TOT's work, especially when a mistake is made or you don't realize the transmit button is pushed, it will work and save your radio from damage and possibly you from some embarrassment. B: Someone is always listening, so keep in mind what you say or do on the radio, especially if you work for a public safety organization because if you say the wrong things you could find yourself in quite a bit of trouble.