Unfortunately the FCC's rules around the Ham bands and digital modes ends up restricting a lot of potential for advancement and experimentation.
I don't think it's particularly limiting, as you can still use cryptography for purposes other than "obscuring [the message's] meaning", e.x. authentication. You just can't encrypt the payload.
It's also likely necessary to prevent the bands from being overrun with people using them for commercial purposes.
- Baud rate vs symbol rate vs bandwidth occupied
- No spread spectrum south of ~2.4GHz
- New protocols/modes are a catch-22 of needing to be well known to be legal but then how do you create a new one from scratch?
- Use-case specific power limits, like radio control.
- "Gotcha" technicality fines like incidental broadcasting of music or "fleeting" curse words. Intent and pattern of behavior isn't considered.
Spread spectrum usually requires significant bandwidth, and there just aren't amateur bands below 222MHz that are large enough for that to be truly useful. (The lower limit is 222MHz AFAIK, not 2.4GHz.) Even the 222MHz band is only 3MHz wide, and the largest below that is 4MHz. Spread spectrum starts to make more sense at higher frequencies with 50+MHz bandwidth. If you have examples of SS uses that could work well on the order of kHz instead of MHz, I'd be interested in learning more.
You can absolutely create a new digital mode protocol from scratch. You just need to make the protocol publicly available and let others know what you're doing. You could do a CW or SSB voice transmission before and after each transmission of your custom protocol, explaining where to go to find out more information. (And of course, station identification.) I'd recommend experimenting on some of the wider/shorter-range bands like 70cm first though, and QRP.
This also applies to encryption - if you make the decryption keys publicly available, and you make it clear how others can decrypt what you're transmitting, it is possible to experiment with radio encryption on amateur bands. That goes to the nature of amateur radio - learning and experimentation. But what you can't do is use it for private purposes - there are other bands for that (i.e. ISM). Most of the conversations around this are people frustrated that they can't browse HTTPS sites or have private communications on amateur channels. It would be nearly impossible to ensure people aren't hogging the amateur bands for inappropriate purposes if you can't decrypt/decode what is being transmitted. With such limited bandwidth available, especially on some HF bands as small as 50-100kHz, prohibiting encryption helps ensure equitable access for everyone. It's like complaining about not being able to drive a non-street-legal vehicle on highways. You can still take that vehicle to off-road tracks if you wish and have fun.
Power limits - I don't know what to say on this one, other than if you have a good case for exceeding them for a specific use, contact the ARRL or your regional radio organization. Drum up support in the community. If there's enough interest and justification, rules can change. But QRP is sometimes a fun challenge too.
As for fines, I have not heard of fines being issued as "gotchas" or for minor infractions. Do you have examples? Most of what I've seen are people causing blatant intentional interference or flagrantly violating the rules with inappropriate behavior, repeatedly after several warnings.
Otherwise, there are many data protocols, even new ones developed for ham networks, in ~10mbit range for IP, eg:
Yeah, it doesn't scale to the moon, but that's the whole point: it's a proving ground, not a moon rocket.
People expect a modicum of privacy which ham radio, to its detriment, denies.
I think it is worth asking why modern digital radio standards (e.g. P25, DMR, LTE, 5G) were largely developed outside the ham community. My survey level understanding is they came from the communication needs of their users and are not a natural evolution of something that hams would build, with or without encryption. When I was researching DMR, there's a lot of stuff that is unnecessarily clunky when considering the use case of a ham QSO. Conversely, the business users of DMR want more structure than what's provided with amateur-designed digital modes. With 5G, I think there are some real technical and capital barriers, i.e., very few amateurs have access to the grade of test equipment needed to engineer and experiment with systems at those frequencies.
That level of permissiveness can be problematic because some technologies are by their nature not compliant. FHSS comes to mind. Its not encrypted but if you don't know know the sequence it might as well be. WiFi, bluetooth and most cell protocols use FHSS. So if you wanted to experiment with digital data transfer and make it in any way robust in a congested area you could not do so as a Ham. Its implicitly illegal.
To your second point I agree. DMR, P25, TETRA etc were developed with police departments and such in mind. To get the full use out of them requires a heavy investment infrastructure for trunking systems. And their programming models assume a set it and leave it use case where the operators are not trained or even savvy to RF comms.
This makes them at best clunky for Hams. DMR has caught on not because its the best, but I think because its easier and cheaper for radio makers to license it. In Europe Type 1 is also allowed unlicensed which gives the market momentum.
No one cares...
You're only allowed to transmit square on center of the allotted channels, and, this is the important bit, one person at a time. All the modes that JT invented flat out ignore both rules for 60 meter transmissions.
I don't care, but I get sick of people telling me that my pactor modem is "illegal".
Also these modes being ok or not on 60m has nothing to do with the question I asked?
The sad part is that the FCC has been more interested in maintaining the status quo than actually continuing the spirit of the hobby. There is nothing experimental or ground breaking about talking to someone states away using an HF transceiver that cost $4k in analog FM. That stopped being innovative 80 years ago. There are a lot of interesting things being done with RF that are off limits to amateurs because they require a business license.
But you are talking about normal people using radio for normal conversations. That's a distinct use case. Its something worth discussing, the FCC has lagged behind there too but its not the same thing as Ham.
> What it actually gets used for is Boomers chewing the fat
I'm only one data point, but I doubt my generation would 'chew the fat' on a call that anyone else in a wide radius would be listening in on. Not, at least, about anything that's personal. That's the point of my postcard analogy.
Uh, they might LARP in your neck of the woods but my county HEAVILY relies on amateur operators for weather related emergencies all year long (tornado country plus snow country).
It's the primary reason my wife and I are getting into amateur radio.
Sadly nothing is really stopping anyone from buying radios online and transmitting garbage. Sure the FCC will come knocking if someone flagrantly transmits without regard for others.
I don't mean "chase a squealer with a truck and a dimensional antenna," either, I mean persistent always-on infrastructure to plot emissions on a map. That's a hobby thing now.
Course if you want to work on the HF bands then it requires a bit more work to get the higher class licenses.
I'm working 60-70 hours a week, plus class, plus church responsibilities and I'm consistently getting 70-71% correct on the General already just from using the app for a half hour or so a day and listening to the question pool via KB6NU's book while I work since Monday morning. I probably won't get up to passing it Saturday but I can just do an online test in the next few weeks once my Tech is in the database Monday or Tuesday.
Getting the General gives you plenty of room to do stuff like this.
I don't want to discourage anyone, but the investment in effort and money between tech and general is in the 4-5 digit range of dollars and hours.
By all means study. But cramming the test questions isn't studying and will leave you as an appliance operator that will constantly be told, if ever on the air, that they're doing something either rude, against the rules, or dangerous.
A good chunk of the questions are memorizing frequencies and wattages you're allowed to use for various things... something you can print off on a chart and tape to the wall.