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Hacking Ham Radio for Texting

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Re: Hacking Ham Radio for Texting

#41

Post by trcarney »

giantrobot wrote: post #33
abfan1127 wrote: post #9

Earlier quoted context omitted.

FCC rules won't allow encryption. I'm not sure why the rules were made originally.

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 were using frequency hopping.

>you're still monopolizing part of a very small band with a private conversation preventing others from using the shared resource

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.

>Error correction necessitates a higher duty cycle

This is true and is why encrypted signals have lower data rates. So instead of having a longer transmission you lower the data rate to get the same effect.

Re: Hacking Ham Radio for Texting

#42

Post by tlrobinson »

thereddaikon wrote: post #5
mikece wrote: post #2

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).

Unfortunately the FCC's rules around the Ham bands and digital modes ends up restricting a lot of potential for advancement and experimentation.

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 commercial purposes.

Re: Hacking Ham Radio for Texting

#43

Post by unoti »

logfromblammo wrote: post #38
jrockway wrote: post #27

Earlier quoted context omitted.

Encrypted communication is not allowed on the ham radio bands.

One could still run a numbers station? There's no way to prove the code words have any meaning beyond what is obvious.

> One could still run a numbers station? There's no way to prove the code words have any meaning beyond what is obvious.

I'm not so sure one could, legally. A number station would broadcast regularly a one-way communications, with no clear meaning. Here's an excerpt of the law from FCC part 97, which is actually surprisingly short and readable. It prohibits:

"messages encoded for the purpose of obscuring their meaning, except as otherwise provided herein; obscene or indecent words or language; or false or deceptive messages, signals or identification.

(5) Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services.

(b) An amateur station shall not engage in any form of broadcasting, nor may an amateur station transmit one-way communications except as specifically provided in these rules..."

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D...

Re: Hacking Ham Radio for Texting

#44

Post by hmrr »

logfromblammo wrote: post #38
jrockway wrote: post #27

Earlier quoted context omitted.

Encrypted communication is not allowed on the ham radio bands.

One could still run a numbers station? There's no way to prove the code words have any meaning beyond what is obvious.

That’s a sure way of ending up with several old men yielding yagis like swords descend upon your house.

Re: Hacking Ham Radio for Texting

#45

Post by Steltek »

tlrobinson wrote: post #42
thereddaikon wrote: post #5

Earlier quoted context omitted.

Unfortunately the FCC's rules around the Ham bands and digital modes ends up restricting a lot of potential for advancement and experimentation.

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 broadcasting of music or "fleeting" curse words. Intent and pattern of behavior isn't considered.

Re: Hacking Ham Radio for Texting

#46

Post by detaro »

edrxty wrote: post #21
generalizations wrote: post #13

Earlier quoted context omitted.

It's not that it doesn't scale - it's just there's a reason people use letters to communicate and not postcards. People expect a modicum of privacy which ham radio, to its detriment, denies.

It also completely prevents any interesting radio experimentation. There isn't anything left on that frontier that couldn't be conflated with encryption.

What's more conflated with encryption than e.g. the level of encoding you find in DVB-S or FT-8?

Re: Hacking Ham Radio for Texting

#47

Post by thereddaikon »

jmwilson wrote: post #32
edrxty wrote: post #21

Earlier quoted context omitted.

It also completely prevents any interesting radio experimentation. There isn't anything left on that frontier that couldn't be conflated with encryption.

As someone who once believed this, this statement is simply not true. Experimentation in ham radio is largely about the physical layer, with maybe some layer 2-4 work when it comes to building low-scale communications infrastructure. Encryption is not implemented at this level, and the limitations on encrypted content do not impede research into new digital modes or actual radio science. I think it is worth asking wh…

To your first point I think you are missing their meaning a bit. There is actual encryption, like AES. And then there are communications methods that aren't open by default. The way in which the FCC regulations are penned means Ham transmissions can't be private in any way. So no just actual encryption but pretty much anyone with a compatible transceiver should be able to listen in to what you are saying at any time.

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.

Re: Hacking Ham Radio for Texting

#48

Post by rmason »

provobro wrote: post #6
thereddaikon wrote: post #5

Earlier quoted context omitted.

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

Getting a technicians license is probably easier than you think. I've heard of amateur radio clubs putting on all Saturday classes with people taking the test at the end. VHF radios aren't expensive, in fact they're importing some from China that are dirt cheap.

Course if you want to work on the HF bands then it requires a bit more work to get the higher class licenses.

Re: Hacking Ham Radio for Texting

#49

Post by spiritplumber »

livueta wrote: post #36
jrockway wrote: post #28

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...

Came here to post this; also, https://meshtastic.org/ . Still in (very) active development, but it genuinely works quite well and is very exciting. Imo lora and similar protocols are a great example of the innovation fueled by the existence of the ISM bands.

https://www.f3.to/cellsol/ This one is geared towards low power consumption, for throwies.

Re: Hacking Ham Radio for Texting

#50

Post by ajsnigrutin »

thereddaikon wrote: post #5
mikece wrote: post #2

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).

Unfortunately the FCC's rules around the Ham bands and digital modes ends up restricting a lot of potential for advancement and experimentation.

I'm not sure about the FCC, but usually, only encryption is prohibited.

Otherwise, there are many data protocols, even new ones developed for ham networks, in ~10mbit range for IP, eg:

http://lea.hamradio.si/~s53mv/nbp/nbp.html

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