Hacker News Reader

Comment by rthomas6 | Hacker News Reader

I think a lot of young(er) people like me who would otherwise get into ham radio are being sniped by SDR. You can buy a $30 piece of hardware and listen to planes talking to the airport, see weather imaging from satellites, intercept and read pager messages, listen to emergency and police radio, listen to all channels of consumer grade walkie talkies, and also just generally see the invisible world of wireless communications going on around us. For a few hundred dollars, you can transmit things back. All on frequencies that require no license with equipment that is very cheap compared to ham radio.

View on HN

As someone who holds but doesn't use a Technician Class license, I completely agree.

As someone commented below, sending encrypted data over HAM frequencies is not allowed (IANAL), which also rules out a lot of interesting projects and use-cases.

There is a proviso that goes with that. If you're doing a metro-area mesh network (some of the WiFi overlap with the 2.4GHz amateur band!) you can use WEP or WPA as long as the password for joining the network is "publicly available." Putting the current password on the website for the club/group running the project is sufficient to demonstrate, for FCC purposes, that the communications are open.

What happens if I use SSL over the top of such a network? Is that allowed? If the answer is yes, it seems more like a loophole in the rules than anything.

Probably not. These rules were put in place to prevent spies from using HAM to exfil data during the Cold War. Really I think it should be something that should be revisited but I don't know how the 3 letter agency's would like a method of communication that they can't access.

Preventing commercial use is still a major argument used.

I see that raised a lot as a concern but I can’t imagine it has any legs nowadays.

Previously, in the 1980’s, yes I could see a Taxi/Plumber/etc using amateur radio equipment as a cheaper workaround for their business, but now it’s so much cheaper (and better) to use cellular or, if you really needed business radios they aren’t crazy expensive as they once were.

There's a ton of people using BaoFeng radios without a license. Every once in a while, some ignorant middle manager at a larger company buys a bunch and the FCC cites them.

I’ve actually seen baofengs with little stubby antennas used by various government employees without licenses, for instance workers at the DEQ near me. I’m not a dick so I’m not gonna call the fcc on them, but it’d be funny to see that.

The reason for the rules against commercial activity on the ham bands was originally to keep hams from competing with commercial services, not the other way around.

However, as an ham radio license holder, I would still not want to see our amateur radio frequencies, which are purposefully set aside by the FCC for hobby and experimental use, used for any commercial purposes at all.

Commercial radio has its own spectrum and rules, and the cost to use it is not insignificant. Many businesses in my area still use radio because it is more reliable and controllable than the services provided by mobile operators. A lot of these would absolutely jump at the chance to use the ham bands and ditch their expensive commercial equipment, regulation, and fees if it were legal to do so.

For non-local communications, HFT companies have been looking at the HF bands for years to shave a few milliseconds off their micro-arbitrage transactions (compared to wired networks) and ham radio has the largest chunk of spectrum after the military.

Is that the case? Most spies use/d OTPs which can be used without encryption as per se. (VENONA notwithstanding)

The rules are against obfuscating your communications, which encompasses both encryption and e.g. using code words to hide your meaning.

I remember last time it was talked about on HN a bunch of people argued with me that there was no reason for encryption. When I started talking about mesh networks and control systems I got answers about how I could do that without encryption so what was I complaining about... The other thing I wanted is to be able to fly things outside of line of site (I mean why else would I use HAM to fly it?). Though it looks like you can apply to do that now.

As to the Russian Spies, tech has changed so much that anyone who would still argue this is fooling themselves.

You can send encrypted data over the Internet with substantially more ease, so I think it's safe to call these laws antiquated.

As I understand it, the idea is that it's a "sandbox" or "test" network. Confidentiality implies a "production" use case, and HAM doesn't want to be the venue for those. You can play around with encryption if the keys are public but you can't actually keep secrets. Even if the secrets are non-commercial. It's a place to play with radios, not a personal communications network.

That’s exactly how I got into amateur radio.

First a receiver and fascination with all the signals I could find. Then the discovery that for a couple hundred dollars I COULD TRANSMIT TOO???!!!!!!

Except that my receiver was a “police scanner” and my transmitters were various “walkie talkies” (first CB, then 2m amateur repeaters.)

What you are describing IS radio as a hobby.

If SDR had existed back then, I would have totally tried it out. It’s just Moore’s law making insanely advanced technology accessible.

I love living in the future!

I went through a radio phase a few years ago and got my extra. Then I had kids, then work got busy. We moved a few times.

I still have a quite a bit of gear left, mostly 2M stuff but the fact is I don't really have anyone to talk to and the biggest reason I got into radio (public service/storm spotting/emergency prep) have not been very active here. We do radios for parades, but they haven't activated storm spotters here in nearly 2 years.

If I had more people to talk to, I'd be on it more. But it's hard to get kids 3 kids 6 and under... to get interested in it.

Any recommended resources to get started with SDR?

The sub $30 RTL-SDR and SDR# software, is more or less the defacto standard starting point.

“RTL-SDR” is amazing!

“RTL” is from a particular chipset that has great support for hackability.”

There a few different apps that can decode signals from it.

I even got a USB-OTG (“on-the-go”) adapter and used my RTL dongle with an app on an Android phone. And that was 5ish years ago.

Get this one: https://www.amazon.com/dp/B009U7WZCA/ref=cm_sw_r_cp_apa_i_jl...

Or this nicer one: https://www.amazon.com/dp/B011HVUEME/ref=cm_sw_r_cp_apa_i_Zl...

Sdr# for Windows. GQRX for the others. For a blog with help and project ideas check out http://www.rtlsdr.com/

See this post I wrote in an earlier thread:

https://news.ycombinator.com/item?id=23468796

You can even get started without buying anything, there's an SDR website where you can experiment with a remote SDR. It's in the Netherlands.

Just browse to here: http://websdr.ewi.utwente.nl:8901/

I have a couple of NESDR Smart dongles from NooElec [1], that have worked very well for me. I run them on a Raspberry Pi 3 and pipe audio output to my desktop or laptop with PulseAudio.

Aside from SDR# on Windows and gqrx on Linux, there's also GNU Radio [2] and a variety of lightweight applications that can run on, let's say, a Raspberry Pi Zero [3]. Oona Räisänen has a fascinating blog that touches on digital signal processing as well, applicable to SDRs as well.

Me? No ham license, but that may come someday.

[1] https://www.nooelec.com/store/

[2] https://www.gnuradio.org/

[3] https://osmocom.org/projects/rtl-sdr/wiki/Rtl-sdr

[4] https://www.windytan.com/

Specifically you're talking about RTL-SDR, a hacked soundcard that can receive a lot of frequencies. The channels you can legally transmit back on for a few hudred dollars more are FRS/GMRS family/business radio channels. (Speaking about USA only here, since that's the only radio location I know about).

tl;dr for the rest of my post: ham radio is the best type of radio for hackers.

Undoubtedly you can have tons of fun with a $30 RTL-SDR and basic antenna, but there are lots of things you can do with ham radio once you grow tired of that, or if you find yourself being interested in how radio works generally, but more fundamentally, you can actually talk to people who are _actively hacking on the same types of things you are_ using projects you've both worked on, maybe together.

Regarding FRS/GMRS walkie talkie frequencies: these are UHF (Ultra High Frequency) frequencies, which means a couple of things: range is limited to well under a mile in most conditions, and building a radio to work on FRS or GMRS would be _possible_, but would require a lot of specialized equipment and maybe an engineering degree. Additionally, power is extremely limited on these radios, so you might be able to transmit back, but you'd better be near the business's parking lot to do so legally. Again, as far as a hobby goes, try breaking in on the Chik Fil A drive-thru attendant's recitation of someone's waffle fry order to ask whether you're coming in clearly on your home-built radio.

Ham radio has a community that's thriving and full of fun for new and/or young modern hackers. You just have to know where to look. For starters, consider Ham Radio Village at DEFCON (https://hamvillage.org) or the online Young Amateur Radio Club (https://yarc.world/) (an inclusive and active club centered around a Discord channel full of people interested in the latest tech in ham radio), or Ham Radio Workbench Podcast (https://twitter.com/HamWorkbench) (a podcast focusing on the latest in ham radio with a focus on new technologies and the intersection with the maker sphere). Hackaday frequently hosts new, fresh takes on ham radio hacking as well.

I think ham radio is back to its roots. With the resources of the modern maker movement, it's possible to learn about radio and hack something together that puts you on the air with people as excited as you are.

thanks for those links.

If you want to build an SDR for HF frequencies that plugs into a soundcard check out the ZetaSDR http://www.qrz.lt/ly1gp/SDR/

RTL-SDR is a TV tuner, not a sound card.

You could build a radio that transmits on FRS frequencies, but it would be illegal unless you submitted a radio to the FCC and received type approval. FRS radios must be type approved, limited power, and with non-removable antennas.

I think GMRS radios must also be type approved, but they can have removable antennas. You need a GMRS license to operate one legally. FRS does not require a license.

"...breaking in on the Chik Fil A drive-thru attendant..." Seriously? Come on.

Other than those nits, you do have a lot of good information in your comment, so thank you for that!

Yep, you are right. Apologies for the misinformation there - I had misremembered.

Good to know about FRS and GMRS. Those things just underscore how really limited experimental transmission privileges are without a ham license.

About the Chik-Fil-A thing, that was a silly way to say that even if you do transmit on FRS or GMRS, it's not like there's a community of other experimenters making it fun to do so.

Reply on news.ycombinator.com