51–60 of 81 posts
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Unfortunately the FCC's rules around the Ham bands and digital modes ends up restricting a lot of potential for advancement and experimentation.
That and anyone using this would need a ham radio license
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Yes, people are checking. Repeated abuse of ham radio (in the US anyways) will eventually get enough hams mad that they will report to the FCC, which does investigate and crack down from time to time. No, it isn't an instant 100% chance of retribution.
People are checking FM because it's trivial. I have yet to hear of someone getting caught using digital encryption entirely through band monitoring (ie not doing something obviously stupid elsewhere like bragging about it on social media)
One call to a regulator, and it's done.
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Encryption is indistinguishable from noise. So the difference between a high power encrypted transmission and high power jammer is semantic. Radio transmissions also propagate. Sometimes they propagate in unexpected ways reaching much farther than expected. If you combine these things you end up with encrypted transmissions raising the noise floor for everyone in a band with no way to know if that noise is a transmis…
> Encryption is indistinguishable from noise. So the difference between a high power encrypted transmission and high power jammer is semantic The difference, from an RF perspective, of an encrypted signal and a non encrypted signal is non-existent as the encryption takes place before the modulator. Therefore encrypted signals won't impact the noise flow for everyone in the band. This would only occur if the operator…
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Encryption is indistinguishable from noise. So the difference between a high power encrypted transmission and high power jammer is semantic. Radio transmissions also propagate. Sometimes they propagate in unexpected ways reaching much farther than expected. If you combine these things you end up with encrypted transmissions raising the noise floor for everyone in a band with no way to know if that noise is a transmis…
> Encryption is indistinguishable from noise. So the difference between a high power encrypted transmission and high power jammer is semantic The difference, from an RF perspective, of an encrypted signal and a non encrypted signal is non-existent as the encryption takes place before the modulator. Therefore encrypted signals won't impact the noise flow for everyone in the band. This would only occur if the operator…
While the encrypted transmission will look like a regular digital mode the fact it can't decrypt the decoded symbols means it's effectively noise. Ham bands are for all hams. There are innumerable other ways to have a private conversation with targeted recipients.
> Depending on the technology used in the receiver, this also isn't true. There are numerous techniques to allow for multiple carriers on the same band. CDMA for example would allow for this. It would take some coordination to make sure each carrier is using a different code but should be feasible for amateur radio operators. It all depends on how sophisticated their receiver is.
Ham bands already have de facto CSMA, you wait for open air to transmit.
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I assume you're referring to the rule prohibiting "messages encoded for the purpose of obscuring their meaning" (e.x. encryption). 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 c…
Encryption is a nerd sniping/clickbait topic. I would argue there are other rules with worse impact: - 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 broa…
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.
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That and anyone using this would need a ham radio license
IMO that's a great way to set up a sandbox: it has built in crowd control and a mechanism to keep out flagrant abuse. Yeah, it doesn't scale to the moon, but that's the whole point: it's a proving ground, not a moon rocket.
Texting via APRS has been a thing for about 20 years. It's also a fantastic way to publish both your phone number and the numbers of the people you are texting in an easy to skim format. Digital modes is one of the areas where the HN crowd could introduce significant advancements to Amateur radio (while pissing off all of the older HAMs who just want to talk about the weather on 40m).
After all APRS is just a protocol atop AX.25.
To be honest I never saw the fun in APRS. I don't want to broadcast my position all the time. And that's really all its used for, save the occasional 1:1 text message.
When APRS became popular it took the whole packet group chat thing away. That was a bit like IRC. The old packet radio had much more to offer. It was amazing because the internet wasn't available to us at that time and BBSes required phone calls by the minute. Being online all day would cost more than a monthly wage. But I could be online and chat on packet all day for free.
But because its speed never continued scaling up, it was just too slow for anything but APRS in the end. It's sad that this whole community has gone. I kinda hoped the Digi modes would bring something back but it's mainly just voice. International group voice which is in itself amazing but I miss the chats.
I think if this interests you, you'll like the LoRa-based devices better. They're unlicensed, so you can encrypt, use it without a ham radio license, etc. LoRa is pretty proprietary which is evil and all, but the end result is good. Hackaday has some good example projects: https://hackaday.com/2020/04/25/a-lora-im-me-for-the-end-of-... https://hackaday.io/project/171790-armawatch-armachat-long-r...
With the kind of power we can use compared to the ISM bands this kind of robust protocol would have a huge range.
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IMO that's a great way to set up a sandbox: it has built in crowd control and a mechanism to keep out flagrant abuse. Yeah, it doesn't scale to the moon, but that's the whole point: it's a proving ground, not a moon rocket.
> IMO that's a great way to set up a sandbox: it has built in crowd control and a mechanism to keep out flagrant abuse. 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.