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Comment by edoo | Hacker News Reader

They don't allow any prototyping or experimenting on the amateur bands either. That is why this is using the unlicensed ISM bands.

I want to see it adapted for the lower frequency ISM bands. I just got into ham and SDR this last year and I'm looking forward to making a super long distance super low speed link to my buddies on the other coast as a backup comm channel in case the primaries go down.

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Not true.

Many things have been prototyped in terms of communication modes. Just a few examples WSTJ, FT8, PSK31, MSK are all developed by hams for hams.

And there is along and continuing tradition of building your own radio.

http://www.arrl.org/news/fcc-turns-away-petition-to-permit-e...

Despite that petition being denied, Part 47 97.309[1] is pretty clear that as long as the mode's "technical characteristics have been documented publicly" it's fair game, subject to 97.307(f) [2].

[1] https://www.law.cornell.edu/cfr/text/47/97.309

[2] https://www.law.cornell.edu/cfr/text/47/97.307#f

This doesn't mean you can't prototype or experiment on the ham bands.

Provided you stay within the limits of your license you are welcome to experiment all you like.

Additionally, if you want to exceed the normal limits of your license then you can apply for an experimental license.

If I'm reading it right, the FCC denied the petition because you're already allowed to experiment on the ham bands. The whole point of the ham bands is experimentation!

That petition doesn't say what you think it does.

The response of "no" was really more about the flaws in the petition.

Who is "they"? Unless I'm confused (which is certainly possible), the 433 MHz ISM allocation doesn't exist in the US. There's only the 420-450 MHz ham allocation.

Is there also a ban on encryption in the countries where it exists, or is that an FCC-only thing?

433.92 ISM is only EU/Africa. So yeah in the US it would be illegal to use encryption. There are quite a few lower frequency ISM bands that might offer much greater range.

I'm interested in this stuff because I just started playing with these: https://cdn.sparkfun.com/assets/a/a/0/b/5/DS_SX1276-7-8-9_W_...

They do spread spectrum on ISM bands with extremely low data rates for insane sensitivity. I want to see what kind of stable distance you can get with lower frequencies and possibly even lower bitrates.

Ooh, thanks for the link! Yeah I would love to do SSH/Mosh over packet radio but I can't do that with my ham license :(

> They don't allow any prototyping or experimenting on the amateur bands either. That is why this is using the unlicensed ISM bands.

What do you mean? This is running on 433MHz, which is within the 70cm amateur band (420-450mhz)

Oh, 433.92 is only ISM in EU/Africa.

I didn't know that. I'm not too familiar with amateur radio around the world. I know people were able to contact other people around the world, so I assumed the bands were similar.

Most long-distance communications happen in the high frequency bands (3-30 MHz) due to its different propagation characteristics.

I haven’t researched the global commonalities, but I’d wager there’s more consistency in HF than the higher frequencies (VHF, UHF).

> super long distance super low speed link

Interesting, can you provide any more information? How could you do radio that far? Googling shows it is at least 2,092 miles. What kind of radio can go that far?

The HF bands (below 3 and 30 Mhz, also called shortwave) propagate by bouncing of the ionosphere. A major part of amateur radio is using them for intercontinental communication.

https://en.wikipedia.org/wiki/High_frequency

That should have said between, not below.

Also, I'll add a link to http://wsprnet.org/drupal/wsprnet/map . Essentially this shows the transmitter and receiver locations for low power beacons, which might give you a sense of what HF propogation looks like. It will vary according to the time of day and solar conditions.

To expand on the other posters, if you can do voice around the world (a few kHz bandwidth) on those frequencies you should very easily be able to do very low bandwidth modulation for data and at reduced power. It would be nice if I could do typing speed but I'd be thrilled with 1 bit per second. Looking around they do have HF packet capable radios but they are quite expensive. I'm going to research those a bit later.

HF digital modes are very common on the shortwave bands. Look up PSK31, etc.. You can convert any SSB (voice) HF radio to digital by connecting it to a computer's audio card.

That is really cool thank you.

Point to point you would have to get into HF or lower frequencies and use the ionosphere. For the hobby of talking long distance as a competition, check https://en.wikipedia.org/wiki/DXing.

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