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Comment by rtkwe | Hacker News Reader

The amateur public radio bands are supposed to be open and useful to everyone so the broadcasts in those spectra are supposed to be readable by everyone as part of the accessible part. On top of that encrypted transmissions would be basically noise pumped into the system making the open uses more difficult and harder to police.

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> The amateur public radio bands are supposed to be open and useful to everyone so the broadcasts in those spectra are supposed to be readable by everyone as part of the accessible part.

Except that proprietary voice codices are allowed :(

To a certain extent yes. This is only true on frequencies allowing digital voice encoding and they technically are still required to publish the working of the codec and how to identify them even if they are patent encumbered and you can't legally resell or distribute something to decode them.

These protections are to ensure the FCC / government are always able to decode amateur transmissions. These aren't protections for the operators themselves.

I completely agree with your sentiments though, the amateur bands should not allow proprietary commercialization.

Yeah it's a bit of a compromise there it looks like. At the time the only reasonable codecs that existed were proprietary and allowing them with the stipulation that the patents be available on a 'reasonable and non-discriminatory' basis so anyone could make a commercial radio based on the codecs.

At least with a proprietary codec with that patent restriction anyone can still go out and buy a compatible radio and jump right on. And if the improvement to capabilities is large enough the trade off is worth it. It's not ideal but it's much better than allowing encryption where the transmissions aren't accessible to anyone by design.

Been wondering why some of the radios cost way too much and now I am left wondering how much cheaper they would be if those patented codecs were banned or forced to be open for implementation.

The AMBE-3000 vocoder chip (used for pretty much all of the digital modes, including D-STAR and DMR) retails for about $50, before volume discount.

Which is not a small mount of money, but isn't that bad given that most amateur radios (excluding the recent Chinese models) retail for ~$500, and commercial radios retail for $1,000+.

That said, I'm pretty sure everyone would prefer to move to Codec2, but the lack of hardware offerings is a problem. I'm looking forward to the day the first real SDR handheld transceiver comes out so this can be implemented by the open source radio community. It's clear that none of the radio manufacturers are interested in interoperability, much less adopting community standards.

At least there's open source implementations of AMBE nowadays.

This is a dead horse but it isn't encryption.

Yeah there's a big difference between encryption and a codec. Anyone can decode and use the proprietary digital voice codec with appropriate equipment which the licensing board has at least assured won't become a monopoly for one radio equipment company.

While I think this touches on a big part of it, I think the bigger thing is the need for identifying stations for accountability. If there was a protocol that emitted an encrypted blob followed by cleartext/phone callsign, it would probably be more acceptable.

No. It's obscuring the content or meaning and it's not controlling a space station:

§97.113 Prohibited transmissions. (a) no amateur shall transmit (4) Music using a phone emission except as specifically provided elsewhere in this section; communications intended to facilitate a criminal act; 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.

(§97.207 outlines the space station exception)

what about steganography?

While I have heard of its use, it seems making a convincing 'carrier' may be more difficult than it seems with the limited bandwidth, and monitoring. But I may be wrong. In relation to the law it seems to violate the 'open public use' provision, but I am ignorant of the fine print. I do know the fcc is unreasonably good at finding and prosecuting illegal transmissions, but will stop short of incriminating myself or others.

Section 97.113 of FCC rules describes prohibited amateur radio transmissions: https://www.w5yi.org/page.php?id=121

While it doesn't call out encryption by name it more broadly prohibits "messages encoded for the purpose of obscuring their meaning." I take that to include both encryption and obfuscation methods like steganography.

someone has to figure out there's a hidden message first. much like using a 'non-type-accepted' radio. on the internet no one knows you're a dog.

See: Direct Sequence Spread Spectrum. It is possible to communicate below the perceived noise floor of a narrowband signal using much more bandwidth than is actually required for the transmission and intended channel conditions. You can basically encode your data across a much wider range of code points which directly modulate the broadband signal. This generates in RF terms what any unawares outside observer would describe as "broadband noise". E.g. WiFi communicates in 20MHz channels, a DSSS solution could use 100-1000 MHz channels (albeit at a MUCH lower baud). Most use/scanning/jamming/licensing of the airwaves is done in a narrowband context, so this is a sort of strategic way to get around these constraints.

If done properly and using a sequence that only you understand, it is possible to become completely invisible to interception for most practical situations. Someone with RF monitoring equipment could determine the source of broadband emissions, but without actually investigating the design of the physical transmitter they wouldn't ever know conclusively what is happening. This is why the FCC requires you publish the algorithm of the PRNG which modulates the data into the final DSSS signal. If you never do this and take decent measures to ensure your sequence appears as pure noise (simply encrypting your payload would do this), there is little anyone could hope to do to discover your presence if they were listening in the middle.

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