Ham Pairs Nicely With GMRS

Ignoring all of the regulations, band allocations, and “best amateur practices,” there’s no real fundamental difference between the frequencies allocated to the Family Radio Service (FRS), the General Mobile Radio Service (GMRS), the Multi-Use Radio Service (MURS), and the two-meter and 70-centimeter bands allocated to licensed ham radio operators. The radio waves propagate over relatively short distances, don’t typically experience any skip, and are used for similar activities. The only major difference between these (at least in the Americas or ITU region 2) is the licenses you must hold to operate on the specific bands. This means that even though radios are prohibited by rule from operating across these bands, it’s often not too difficult to find radios that will do it anyway.

[Greg], aka [K4HSM], was experimenting with a TIDRADIO H8 meant for GMRS, which in North America is a service used for short-range two-way communication. No exams are required, but a license is still needed. GMRS also allows for the use of repeaters, making it more effective than the unlicensed FRS. GMRS radios, this one included, often can receive or scan frequencies they can’t transmit on, but in this case, the limits on transmitting are fairly easy to circumvent. While it isn’t allowed when programming the radio over Bluetooth, [K4HSM] found that programming it from the keypad directly will allow transmitting on the ham bands and uses it to contact his local two-meter and 70-cm repeaters as a proof-of-concept.

The surprising thing about this isn’t so much that the radio is physically capable of operating this way. What’s surprising is that this takes basically no physical modifications at all, and as far as we can tell, that violates at least one FCC rule. Whether or not that rule makes any sense is up for debate, and it’s not likely the FCC will break down your door for doing this since they have bigger fish to fry, but we’d definitely caution that it’s not technically legal to operate this way.

37 thoughts on “Ham Pairs Nicely With GMRS

    1. Licensed Ham radio operators are allowed to modify non ham radios, BUT those radios are not allowed on NON-HAM bands anymore. At least that is the situation in almost any european country with PMR, LPD and SRD devices. Once modified, they forfeit their original allowance on their own bands.

    2. Came here to say this, thank you. A licensed ham can even build their own radio from scratch and use it legally (I’ve done it). What is not legal is for a ham or anyone else to operate on a licensed frequency (GMRS for example) without the required license. Also, MURS does not require a license, as long as you’re using a type-accepted radio you can treat it like the VHF cousin to FRS.

      1. The issue is the manufacturers of GMRS radios are not supposed to make it this easy to transmit out of band. There is nothing wrong with amateurs modifying said radios, though.

  1. The amazon ad in the US shows a frequency in the ham band on the display. It also says it “Real 10 Watt Power TIDRADIO TD-H8 is a dual band ham radio with TWO POWER TUBES”.

    Wow that’s retro!

  2. The FCC physical modification rule for the one service is to limit the ERP and therefore static range footprint of the device – so that one can’t(or shouldn’t) put up a Yagi to boost the ERP, increasing the range footprint. The other service was originally intended to be licensed and such limits were not imposed.

  3. Should the radio have limitations built in? If you are licensed in both services and follow the rules applicable to each, what’s the problem? Certainly the restrictions for each service could be programmed in.

  4. Don’t encourage this. These aren’t type accepted for GMRS/FRS/MURS. Who knows what sort of interference, spurious emissions and general crap they scatter around. Someone needs to read Part 15.

    1. The point is that the legal burden is on the party selling the radio for type-accepted use. And, clearly, it worked as intended in this case; the radio is no longer available from the party who was misrepresenting its type-acceptance. It’s not the _radio_ that is illegal, at the end of the day…

      One rule for type acceptance is that the radio cannot be trivially made to operate outside of its authorized bands and authorization. A radio that can be trivially reprogrammed is… iffy. But not clearly illegal. Quite a few motorola commercial radios are reprogrammable (as are many other radios by similarly reputable vendors), but since they’re not “trivially reprogramable” by a normal user, they are type-accepted.

      Legally, a user prepared to modify the radio or to take other nontrivial steps to bypass or reprogram its restrictions doesn’t count as a type-acceptance violation for the radio maker, because the radio was necessarily altered from its type-certified state by a third party. The third party bears any legal burden for ensuring compliance or liability for noncompliant use.

      Now, from the other side, it’s even less of a problem. A licensed radio amateur is, at least in the US, fundamentally not restricted by _how_ he creates the signal, only by whether the signal is a signal he’s legally allowed to transmit (frequency, spectral purity, mode, and content).

      There is, as far as I know, only one notable and historical exception; it’s not legal to create a signal by means of spark-gap transmitter, simply because at the time the rule was passed, there was no plausible way for anyone to make a non-interfering selective signal using a spark gap, and no likelihood of that changing in the foreseeable future. Even the spark-excited resonant-circuit transmitters tended to be filthy and unstable, as well as blanking large swaths of the bands for miles around them. There were already fundamentally cleaner (and massively longer-ranged for similar power) solutions available, so spark transmitters were blanket-banned.

      Thus, these days, even if you were to create an otherwise fully-filtered spark-originated signal, that otherwise met all technical limits and would not otherwise be objectionable, the historical “no spark transmitters” rule would still render it illegal.

  5. It makes no sense to be forced to buy two different radios when I am licensed in both bands. Sounds profit driven to me. Can’t one radio be free of spurs in both GMRS as well as HAM bands, and be type accepted in both?

    1. Sure, it COULD be, but that would require a lot more engineering, would be more expensive to build reducing the profits for the manufacturer, and I don’t think you would ever get a radio type accepted that did the ham bands as well as GMRS/FRS/MURS. Way too much temptation for a FRS person to start using the local 2M repeater without getting a ham license.

      1. That’s an old story. Back then, LPD was in the middle of the 70cm band.

        Being part of the ISM band, it had to be tolerated (or ignored) by amateurs. However, in theory, licensed amateurs could also use these radio gadgets to talk to each others using their call signs. A third person without license couldn’t participate, though. Weird times.


      2. Actually, you can’t combine GMRS and another service in the same radio by rule. If you look, you might find some pre-rule change radios that combine FRS or GMRS with another service, such as the Standard Horizon marine HT that also did FRS…

    2. That’s not really the issue.

      Government compliance rules are like steering a supertanker; they cannot turn on a dime. Even necessary changes take forever and have unavoidably high costs, so rules don’t tend to change for “mere improvements” of status quo. Thus, to understand them, you have to go back to see why they _historically_ made sense, not why they make less sense now.

      Type-acceptance was envisioned as a way of preventing easy in-good-faith misuse of radios on the “wrong” bands, without forcing most users to actually know what the rules allowed them to do. Among other things, it was part of an effort to not require full commercial radiotelegraph licenses for all parties involved in things like taxi dispatching. It wasn’t the _beginning_ of that effort, but it was yet another step on that road. And the main driving force was that, as radio became MASSIVELY more useful in society, the cost and burden on the FCC grew at an equally massive rate. This was unsustainable, because there simply weren’t enough tax dollars (even in total!) to allow the FCC to continue with the previous regulatory regime…

      These days, the same effect could be more simply achieved by simply sticking license and callsign details on a sim and making the radios respect the sim-defined limits. But at the time the type-acceptance solution was created, any such technical solution would have been fraught with complicating details.

      Another historical complication was that signal filtering was inherently not broadband (at least not if you wanted to keep the price reasonable), so even if you used the same basic radio chassis to create radios for adjacent ham and business bands, the filters would be physically different. You could increase the cost (and physical size) of your radios, but 99% of your customers (for either radio) would not benefit from the extra capabilities even if it were legal to offer them.

      This is why a lot of older ham radios, if altered to cover the extended MARS bands, tended to generate nasty sloppy signals when operating outside the designed bands. Or, if whoever did the alteration also redid the filtering to remain technically compliant in the MARS bands, the ham-band performance and signal hygeine suffered.

      The reason why many of the cheap chinese radios have such foul signals is that, rather than bothering with all the usage-specific filters, the designers just directly amplified and modulated the raw signal from the digital oscillators, along with all of its phase noise, and threw that at the antenna directly. If used with a narrowband antenna, they’re actually often clean enough to comply(in spirit, not necessarily in specification) with FCC spectrum rules. But if they’re feeding a broadband antenna (they almost always are), the out-of-band unintended signal gets transmitted as efficiently as the actually-wanted signal.

      Another detail: the original type-acceptance regime involved verification tests in an FCC lab. Today, even if every single FCC employee did nothing but confirmance testing, and managed to verify ten pending devices per hour, the backlog would build up at a rate of multiple years per year of requested-but-not-yet-tested devices. So, these days, they use declarations of conformity, and apply fines and import blacklists when a declaration is found to be false. And even under the reduced burden, the system is still creaking…

      1. There are certified, accredited labs that do compliance testing now… quite a few of them, available to anyone that can pay them for the tests and wait in line; the FCC itself does very little and subs out most of the work nowadays – even in compliance legal actions.

  6. If you ever needed proof of why Amateur Radio has gone down hill, look
    no further than some of the comments here and the article itself.
    (“Yea I know it’s illegal but don’t care cause it’s cheap”)
    No knowledge tests and NO FCC enforcement. Real shame.
    AR ops were once looked up to, no more.
    The lack of knowledge and understanding of how NASTY these
    CHEAP radios are is just scary.
    I tested one and the 2nd harmonic was only -24db down(VERY ILLEGAL )
    “I want it cheap, now and without any work” is the new motto.

    1. Well, I suppose that’s because USA and UK (?) have Technican class which is just a handful of questions. It’s nice to get started and does improve statistics, but.. Well.. The question is, do these guys/gals really feel being part of a community, do they share the ideals of the ham spirit? Or do they do the test just for fun, then go off to the amusement park? I seriously don’t know the answer. 🤷‍♂️

      I mean, if you have basically nothing to invest, to accomplish, do you take the hobby/service as serious as if you had to learn for months ? Because, you will only go through all the trouble if amateur radio really means something to you, roght ?

      It’s in parts a bit like learning for a driving license, essentially. If you don’t really need it or if you have no affection to the automobile hobby, you won’t go through all the trouble.

      1. I agree with all of the above however, I know that people who play with radios as toys will eventually lose interest and just go away. The second type of people who have an interest in radios are preppers and survival enthusiasts. In general, the later, over time become really good HAMs and just join the rank and file. Reason for that is funding and education are slow processes. We all live in weird times right now and tolerance is important.

        Amateur Radio in general is going through transformations that will modernize the “hobby”. The arrival of the full 5G/6G cellular implementations will change things even more over time so, hang on for the ride. In the mean time, the FCC is correct about going after the manufacturers and distributors of devices that do not meet their requirements.

        All we can do as HAMs is sit back and watch, do not encourage by engaging, work with your government representatives, vote and enjoy what is left of the hobby that interests you the most.

      2. The general and extra classes are just a “handful of questions” away too. The questions are harder than the technician questions, but still not very hard for somebody who spends a little time studying.

        There was a time that you had to pass a morse code test for them, but that was done away with in 2007 or so.

      3. I think that is only part of the issue. I feel like the real issue is that of cost.
        Back in the day parts were easier to obtain and the price was affordable to the point that a person could build his own equipment and it was something to be proud of.
        In these modern times prices are high and it’s not so easy to scavenge parts.
        Who of us OM would ever have thought about paying $1000 or more for a radio, unless we buy it used, and/or $500 for an antenna. Back then if anyone had told me what I would have to pay now, I would have said they were nuts. The modern HAM still wants to have the pride but has to go cheap because of the higher price of everything it takes just to survive now. If prices of equipment increase at the rate that they have in the past we may see a time when HAMs will be few and far between if not totally absent…AI0DS

    2. HAM elitism is just as much to blame as a lack of knowledge and enforcement. It’s a rarity that I see knowledgeable operators offer to explain the reasoning behind why these comments are problematic.

      Maybe turn this around by focusing on which inexpensive radios are good for beginners and offering to help them learn.

      The community needs to evolve to remain relevant.

      1. This is a wonderful comment. I’m a non ham who has considered the hobby but don’t have enough time/money to invest in a big to-do.

        Are there any of these cheap radios that I could use and justify some investment?

      2. In the beginning, radio was a lab curiosity. Then Marconi spanned the Atlantic, and that was big news. Individuals began to play with radio, the start of ham radio. Marconi wanted to sell or rent radios to ships at sea.

        There were no licenses or rules, though both gradually kicked in over 20 years. The Titanic caused lots of rules. Too much interference.

        Hams never controlled the rules, other than wanting a place for themselves. Ham radio is the least controlled radio service. The others give very limited channel or channels. You can’t build in orher services. They are for users.

        Since hams have to be tested, they likely know more about rules than users of other services.

  7. I don’t really understand the “elitism” comment. I was first licensed as WN6RDG in 1965, and currently operate as AB1LF. I do have a couple of cheap HTs, but most of my radios are kit built or home brew. I am also a professional electrical engineer. Amateur radio is mostly a hobby, but there are times when it can provide vital communications. The saying goes: “when all else fails, amateur radio”

    1. Hi Brent! I think the elitism comment you’re referring to is probably mine. I got my technician and general license in quick succession a little over a year ago. I’ve met a lot of great people through radio, but my online experience has been that the people who post in response to articles like this often seem to just shut down any discussion about anything that may violate the FCC’s rules.

      The general public has no idea why this is an issue and I worry that this instant shutdown response gives people an unpleasant perspective of the amateur radio community. I may be wrong. I also understand that these folks are probably a vocal minority. Still, it does not create the sense of a welcoming environment for newcomers.

      I would really love to see more comments weighted towards explaining the reasoning behind why the FCC made the rules rather than just having people issue an instant shutdown “Because rules”. IE…the problem is that using radios which create spurious emissions is that it interferes with others’ use of the spectrum. It’s just not a nice way to behave. As an aside, the FCC has codified this in their rules.

  8. The regulations are multiple… on marketing, selling, importing, and using. They are all related to protecting users of radios of all types. FCC regulations are voluminous things to read, but that’s what you’ll see if you read through all of it, Part 1 to Part 100 (or whatever the count is today)

    The modern market and international business trends have provided new access to customers that typically don’t know or care about such matters. The FCC’s enforcement actions are typically targeted at businesses or marketers, and seldom the end users of such equipment. You’d have to exhibit a repeated and intentional disregard for the rules to get the FCC to pay attention to you in terms of an enforcement action.

    I worked 15 years years for an offshore manufacturer of consumer electronics devices, primarily FRS/GMRS radios, and dealt with all the device testing and legal ramifications to the business the FCC regulations had.

    I’ve also been an Amateur Radio Service licensee for 47 years and as such built “intentional radiators” as well as “unintentional radiators” with the understanding and respect for all other spectrum users that most Amateur Radio folks have.

    The average consumer buying electronics and even the average Amazon Seller don’t know much of anything about what we’re discussing in the forum

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