14 ms·
Why radio receivers won’t tune 800-900 MHz
- LeoPanthera 6y ago*in the USA. Radio receivers and scanners sold outside the USA, even if they are made inside the USA, have no restrictions. US manufacturers usually label these radios as "export" versions. It reminds me of the early days of web browsers when "export" versions of Netscape and IE only supported a maximum of 56-bit encryption for SSL.
- LMYahooTFY 6y agoI take it that was related to the munitions classification for encryption?
- LeoPanthera 6y agoYep. https://en.wikipedia.org/wiki/56-bit_encryption https://en.wikipedia.org/wiki/56-bit_encryption
- KMag 6y agoAll of the SSL 3.0 / TLS 1.0 EXPORT cipher suites are actually limited to https://en.wikipedia.org/wiki/40-bit_encryption https://en.wikipedia.org/wiki/40-bit_encryption , see for instance page 60 of https://www.ietf.org/rfc/rfc2246.txt https://www.ietf.org/rfc/rfc2246.txt For a while, exports were limited to 40-bit symmetric key strength and 512-bit moduli for DH and RSA. I had forgotten about the limits being raised to 56 bits for a few years before being fully dropped by the Clinton administration. There was a brief attempt to get around the pushback against key length restrictions with the Clipper chip[0]. The idea was to give everyone 80-bit Skipjack encryption while enabling U.S. law enforcement intercept by having the chip refuse to function if it wasn't shown a valid escrow message (LEAF) for the key it was using. Skipjack was classified at the time and supposedly stronger than anything commercially available at the time. The problem was that LEAF itself only used a 16-bit authentication code, so it was trivial to bruit-force another LEAF message that would work with your session key, but yield garbage data in a wire tap. [0] https://en.wikipedia.org/wiki/Clipper_chip#Technical_vulnerabilities https://en.wikipedia.org/wiki/Clipper_chip#Technical_vulnera...
- yuhong 6y agoOnly for one year (1999). I personally wrote this: https://en.wikipedia.org/wiki/Export_of_cryptography_from_the_United_States#PC_era https://en.wikipedia.org/wiki/Export_of_cryptography_from_th...
- gerdesj 6y agoYes. lol. I worked for a chopper factory in the UK back in the day. We had Novell servers. NetWare CAs back then did as they were told and would only offer rubbish encryption. We used it for throwaway stuff and manually cranked out certs with OpenSSL for important stuff. We also watched firewall logs ...
- giantg2 6y agoI would imagine SDRs with "export" software are easy to get and can tune in.
- BenjiWiebe 6y agoSDRs don't have the 800Mhz restrictions.
- jcrawfordor 6y agoA large portion of SDRs have no FCC equipment authorization at all, and so don't necessarily comply with regulations---including the lack of an AMPS lockout. This makes them a little bit iffy for sale in the US, but there is generally a rule that allows "test equipment" to be sold without equipment authorization under certain conditions on its use. I (not being an expert on this, I am not a lawyer, etc) would describe most hobby SDR use as being a gray area, but one that is probably not of too great concern since most hobby SDRs on the market are receive-only and obviously these weird part 15 rules about scanning receivers don't really matter in the modern age. SDR transceivers like the HackRF are probably still not being purchased by people who will cause any trouble, but I do worry a little bit more about unintentional disruption of important radio applications like aviation navaids or whatever. If I were to take a policy angle here, I think it might be a good idea to restrict such devices to people with amateur radio licenses since they are not especially hard to obtain (DE AE5JL). I'm sure there's a thousand people here who would vehemently disagree with me on that though.
- tonyarkles 6y ago> I think it might be a good idea to restrict such devices to people with amateur radio licenses Am a Canadian HAM, and also the owner of multiple transmit-capable SDRs. While I don't disagree with you on principle, one tricky part with that is that the majority of my usage of these devices has been commercial. Requiring an amateur license to do commercial work is kind of the opposite of how the system is supposed to work (i.e. no commercial activity on the HAM bands). The real saving grace for the transmit-capable SDRs is that they're generally quite low power. I think the most powerful one I have can do... 100mW? Sure, you could be disruptive with that, but it's not going to go very far.
- nabla9 6y agoOr GPS receivers not working at high altitude unless you buy some Asian brands with right chipsets.
- t0mas88 6y agoNote that the rules require GPS receivers not to work when above 60,000ft AND at a speed higher than 1000kt. Some manufacturers made that an OR, but that's not required. You're very very unlikely to ever make it above 60,000ft at a speed faster than 1000kt unless you own a fighter jet.
- kzrdude 6y agoSince it's so unlikely, I guess most manufacturers haven't even tested it.
- nabla9 6y agoIf you build nanosatellites or cubesats or do rocketry those limits are exeeded. For example NovAtel OEM-719 GPS has no COCOM limits. Fortunately COCOM limits for GPS are not enforced. It's empty clause.
- t0mas88 6y agoRockets that go above 60,000ft and at 1000kt are the case that this limit was designed for, they didn't want enemy ballistic missiles guided by GPS. Of course that regulation is now useless because foreign receivers don't implement the limit and competing GNSS systems also don't have it. But at the time it was written this was a sensible restriction because it was a unique technology.
- BenjiWiebe 6y agoHigh powered model rocketry can and does exceed this.
- KMag 6y agoThe limit was 40-bits for a while. Maybe briefly in the late 1990s the export limit was 56 bits, but all of the EXPORT cipher suites in TLS 1.0 (from 1999)[0] have limits of 40-bit symmetric keys, or a NULL cipher. Also the RSA and DH moduli for export cipher suites were limited to 512 bits. [0] Page 60 of https://www.ietf.org/rfc/rfc2246.txt https://www.ietf.org/rfc/rfc2246.txt
- matthewmcg 6y agoThe requirement that scanners not be a silly modifiable to restore the AMPS bands was loosely interpreted. On certain older RadioShack scanners, you could unsolder some diodes on the main logic board and full coverage would be restored.
- NovemberWhiskey 6y agoThis is often the case for amateur radio equipment as well - transceivers are configured not to transmit outside the licensed amateur bands, but there is often a simple modification (cut a PCB trace, remove a component, etc) that happens to remove those limitations. These are often called "MARS mods", since the Military Auxiliary Radio System uses HF frequencies that are outside the amateur allocation.
- augstein 6y agoThis blogpost is unfortunately barely readable on a small screen, because of the fixed line widths.
- quercusa 6y agoHe's faithfully captured the 1980s BBS vibe.
- DanBC 6y agoHere's what I get. 1980s BBSs didn't have wrapping this bad unless you were quoting. To start: yes, long time no see. Well, COVID-19 has been like that. Some days I feel accomplished if I successfully check my email. I finally managed to clear out a backlog of an entire handfull of things that needed thoughtful responses, though, and so here I am, screaming into the void instead of at anyone in particular.
- nullc 6y agoBack when analog cell phones were still a thing on the few scanners you couldn't make a trivial modification to enable receiving the cellular frequencies (e.g. switch them into export mode) you could often just tune into some harmonic. I wonder if truckers still call a lot of phone sex?
- layoutIfNeeded 6y agoIn the age of camgirls? I’d doubt it.
- nullc 6y agoWell I really hope people aren't using video erotica while driving!
- sandworm101 6y agoI was in a courtroom once. the case head of us involved a guy who crashed a van while watching "american pie 2" on a then-illegal in-car entertainment system. Judge's first question: Which scene?
- WarOnPrivacy 6y agoIn 1988 I bought a Uniden Bearcat 800XLT, specifically because it didn't lock out cellular frequencies. Listened to lots of (one side of) phone calls.
- breput 6y agoI had (and probably still have) a Radio Shack Pro-2006 scanner from the late 80's. Even pre-Internet, instructions on how to bypass the cellular band block were easily found on Fidonet and local BBSes, and all it involved was removing a single diode. https://www.wentztech.com/radio/Equipment/Pro2006/pro2006mods.html https://www.wentztech.com/radio/Equipment/Pro2006/pro2006mod... It was really a golden time for snoop...er..listening to cellular phones because they were so enormously expensive, including per-minute usage fees, that only drug dealers, doctors, and the 1%-ers could actually afford to use them. So there was always interesting things to hear. Ordinary cordless phones were much more affordable and fairly common at this time. They broadcast in the clear at 49 MHz (at least in the USA) and had no legal protections like the 800 MHz cellular phones.
- ed25519FUUU 6y agoStories please!
- giantg2 6y agoLots of similar stuff in the book The Best of 2600
- sroussey 6y agoOh, those were the days!
- kabdib 6y agoI once overheard a phone interview for a position so interesting that I wanted to apply for it myself. The answer to "How did you hear about our company?" would not have gone well. :-)
- HPsquared 6y ago"word of mouth"
- o-__-o 6y ago
- emersonrsantos 6y ago...And you could use a code on Motorola startac models to listen to these channels very easily. One of my hobbies was to do that when I was waiting for my girlfriend in the car.
- james_pm 6y agoCordless phones were more "fun" to scan since it was generally your neighbours you heard just because of the range of those things. Also baby monitors were (and probably still are) wide open. Literally a 24/7 mic broadcasting for anyone to listen to. Pagers were also easy to listen to. You'd get short messages without context. A lot were office to doctor or dispatch to tradesperson.
- breput 6y agoAs a person who also did this, I feel like it has encouraged my suspicion of communication privacy. All it takes is listening to your married neighbor talking to their boyfriend/girlfriend to realize that someone could be doing it to you. The difference now is that it doesn't have to be within a 150 foot radius.
- heavyset_go 6y agoNow, not only does someone not need to be actively listening, they don't even need to save the audio. Just convert it to text, keep it indexed and whatever three letter agency is doing the tapping has an easily searchable record of your communications should they ever feel the need to look into you without you knowing.
- sterlind 6y agoConverting to text loses data and will fail on unexpected languages or accents. It's better to use a specialized voice codec, which can have fantastically high compression rates, or just keep the (already annoyingly-companded) 8kbit voice stream around in its entirety. It's pretty small.
- pessimizer 6y agoYou convert it to text in order to index it. If it becomes interesting in the future, you listen to the audio (maybe after getting permission from a judge in a secret court.).
- 6y ago
- lsllc 6y agoAnyone have any recommendations on a "modern" digital trunking scanner? (handheld) I have an old GRE PSR-500 which isn't terrible, but I'm looking to replace it as it has next to zero software support for programming it and doing it by hand is a real pain. You'd think in this day and age someone would make a scanner with a companion app connected to Radio Reference for programming. Would be nice to have bluetooth audio too. FWIW, GRE stopped making scanners in 2012, and later closed down and sold off their scanner business to Whistler. Supposedly Whister were going to release a new scanner, the TRX-100, but cancelled it. Seems like handheld scanner technology is still stuck in the '80s.
- ChuckMcM 6y agothat would be the Uniden SD100. I've got the SD200 which is the "console" model.
- wiml 6y agoSince we're on HN, how about an RTLSDR, a Pi, and op25?
- jcrawfordor 6y agoI think much of the scanning crowd has either 1) abandoned interest in digital trunking systems or 2) switched to SDRs, which is an unfortunate state of affairs as the state-of-the-art in SDR trunking decoders is actually pretty bad.
- jcims 6y agoI went hogwild with this at the beginning of the RTLSDR era of SDR. I just started picking it back up after getting some better hardware and was kind of bummed at how little the quality of the voice decoding has progressed despite what appears to be a ton of energy invested. If I recall correctly some of it is licensed and/or patented and people are just having to reverse engineer the protocols. I’d pay for a commercial demodulator to snap in.
- rachelbythebay 6y ago
- ashleyn 6y agoThe article mentions the Oki 900. Here's a Wired article mentioning how hackable it really was: https://archive.is/AEq0B https://archive.is/AEq0B
- myself248 6y agoMENU SND END RCL STO CLR
- throwaway611657 6y ago"GOOD TIMING!" My friends and I used to get piles of old Okis at First Saturday in Dallas. We'd leave Austin at midnight and drive 3 hours to get all the pre-dawn good deals. I remember we got a hold of some mobile data terminals and tranceivers too, though we never quite got around to the mischief we dreamed of using them for. POCSAG decoding was another good time. Ah, to be young again!
- jcrawfordor 6y agoHi all, I am the author. I 1) have no idea how this made it to the top position, 2) now feel much guiltier about posting so infrequently, 3) apologize for the design of my blog being almost actively hostile to users, but then maybe that was the point?
- saurik 6y agoRe 3: if it makes you feel any better--or worse! (most of the time I make people feel worse...)--I have added your blog to my list of "websites whose design I really like" ;P (the only thing I disagree with strongly is the seemingly-fixed word-wrapping, as it causes random-feeling new-lines while reading on my iPhone X screen).
- lostlogin 6y agoI thought those were typos, accidental line breaks.
- jcrawfordor 6y agoYes, the script that generates the website was written in one evening when I was not entirely sober, and it has some weird behavior around linebreaks that I triggered by typo. Somewhere on my todo list is to add markdown parsing so I can do cutting-edge things like indented block quotes while still having the text reflowable for the RSS feed, but then I'll have to decide how to represent headings and links while still keeping to my 80x24 video terminal aesthetic.
- temporallobe 6y agoIf you don’t mind the conversion happening on the front-end side, Showdown.js has worked really well for me on a few projects.
- firloop 6y agoReminds me a lot of reading old GameFAQs guides
- merlinscholz 6y agoIs it just me or does the website raise a cipher mismatch error when trying to access it?
- Sebb767 6y agoSeems we hugged the site to death :( Here's an archived version: https://web.archive.org/web/20201213003741/https://computer.rip/2020-11-28%20the%20verboten%20band.html https://web.archive.org/web/20201213003741/https://computer.... EDIT: Seems to be back up.
- jcrawfordor 6y agooops. everything seems fine on my end, but my whole Enterprise Hybrid Cloud is a single pizzabox in a low-rent datacenter that I "fully manage" by running updates when I remember to. I put it on CloudFlare just to be safe and make sure my packets are adequately mixed with pharma spam for transit.
- joshxyz 6y agoMAN THIS IS THE FASTEST LOADING SITE
- jcrawfordor 6y agoit's inlined for performance because putting the CSS in a different file felt like more work.
- sigmaprimus 6y agoHere is a nice image of the Canadian Frequency Allocations http://canadianspectrumpolicyresearch.org/wp-content/uploads/2016/08/2014_Canadian_Radio_Spectrum_Chart.jpg http://canadianspectrumpolicyresearch.org/wp-content/uploads...
- molticrystal 6y agoAs a child in the 80s I was given an intellivision and a old (even in those years) ~13" black & white tv to play it on. It had the ability to tune to the higher UHF channels 70-83 [0] which while planned for use in tv broadcast, never ended up being used, but they didn't know that at the time of the construction of the tv set. The frequency covered by those channels were reallocated in 1982 by the CCIR worldwide convention, and covered approximately 806 to 890mhz. What was most interesting to me as a young teenager in the early 90s about this particular tv set, was that I found out I could hear an occasional phone call when tuned to those UHF channels, even more so when I used the fine tuning nob. On a side note, the tv set also allowed me to view scrambled channels on the cable system which I could unscramble to various degrees by turning the tuning nob at certain rates back and forth. I suppose modern 90s systems were not designed with my old tv set in mind. https://en.wikipedia.org/wiki/Television_channel_frequencies#Americas_(most_countries),_South_Korea,_Taiwan_,_Burma_(Myanmar)_and_the_Philippines_2 https://en.wikipedia.org/wiki/Television_channel_frequencies...
- jimmyrocks 6y agoI had a TV that did this exact same thing! Except I was given it as a color "monitor" for an Apple IIE. I would spend hours building my own antennas and spinning the fine tune knob to try to bring in far away signals.
- bmcahren 6y agoI'll never forget using grandpa's police scanner trying to find interesting sounds and tuned to one of the ~1800 frequencies and shockingly discovering that the cordless phone we bought in ~2003 was completely unencrypted broadcasting in the clear at half of the frequency I was listening to. My mom was in disbelief and we bought a new phone with DECT shortly after. I was a bit shocked myself.
- jessriedel 6y agoCould somebody summarize the answer please? I'm trying to decide if it's interesting enough to read, and the first 20 paragraphs suggest not.
- tinalumfoil 6y agoI enjoyed it but if you're 20 paragraphs in and bored I doubt you'd find the rest interesting.
- jessriedel 6y agoI've read plenty of technical papers that have interesting ideas buried in tons of bad prose. Holding the interestingness of the central idea fixed, there is no limit to how boring a writer can make things. In general, I don't understand why blogs (and HN) are allergic to abstracts.
- jfalcon 6y agoI think the OP's write up misses one very important piece of the puzzle: Politics. Newt Gingrich who was Speaker of the House at the time got embroiled in an incident that was recorded from a cell phone conversation. https://www.cnn.com/ALLPOLITICS/1997/01/13/tape/index.shtml https://www.cnn.com/ALLPOLITICS/1997/01/13/tape/index.shtml Now fast forward to a few years later with the Patriot Act and metadata controvery that Edward Snowden exposed... same shit, different day...
- jcrawfordor 6y agoI did not know about the Newt Gingrich incident! That really adds some interest. There was definitely a lot of public attention to the issue at the time, and in some ways rightly so, but of course the resulting efforts were misdirected at a legislative fix. A point that I wanted to make in the article but I'm not sure I completely articulated was basically "this is what happens when Congress writes technical regulations," but of course this is far from the most egregious example of that. The parallels to what we see today with pervasive surveillance and anti-encryption policy are significant, and it's frustrating to see how much less atwitter congress is about these issues today, when it's their own government doing the eavesdropping. As I make a jab towards in the article, I think that the people of today (and even the people of then) have given up on the privacy of their personal communications in some ways. I can't blame them, but it's clearly a problem that needs to be solved. Perhaps one way to look at it is this: in many ways, our communications on the internet have fewer privacy protections than our communications on landline phones. How did it get to be this way? History and policy, combined in an ugly way.
- jfalcon 6y agoYeah. Let's put it this way: OKI900's and all that were around before 1992. And that phone was favoured because you could easily reprogram the ESN/NAM/MIN for cloning as well as turn it into a scanner by turning on it's speaker and had control of the frequency. It was a modder's dream to hack on. But the same could be done with Motorola phones with a few more button presses. That was 1992. 1997: AMPS system is waning against D-AMPS and even that is getting pressure from a new standard - GSM - which is also digital and ENCRYPTED. Newt gets caught and to show what a great prick him and Bill Clinton were, they passed a law that was obsolete before it was even passed into law. https://www.wired.com/1997/11/ears-of-the-airwaves/ https://www.wired.com/1997/11/ears-of-the-airwaves/ --- This is why the election system, process of creating lawmakers (congress) as well as judicial system is retarded. The time lag doesn't stop the flash pan crime trends nor does it do anything to improve the situation due to the abuse of absurd laws like this one. This law is rendered null and void by technology long before it was ever enacted...
- icedchai 6y agoI had a Bearcat scanner that let you listen to the analog cellular bands. I think you had to use a harmonic frequency. This was probably 1992 or 93. I never heard anything interesting really.
- bluedino 6y agoWhy are scanners so damn expensive? You’d think there would be Chinese copycats out there for $50
- Triv888 6y agoRTL-SDR can be purchased for ~$15
- rasz 6y ago>not particularly difficult to intercept the call setup process from an AMPS phone and swipe its identification numbers, allowing you to basically steal someone else's cellular service. You can imagine that this was popular with certain criminals with a need for untraceable but convenient communications. and Kevin Mitnick https://www.cnet.com/news/q-a-kevin-mitnick-from-ham-operator-to-fugitive-to-consultant/ https://www.cnet.com/news/q-a-kevin-mitnick-from-ham-operato... "I was cloning my cell phone to random subscribers and dialing into computers from the cell phone."
- rootw0rm 6y agoFREE KEVIN
- exabrial 6y agoGreat example of why every regulation should have an implicit sunset.
- crazygringo 6y agoThat's a fascinating story. I'm curious though -- since the rule no longer has any practical relevance, is it still enforced? Since it's not particularly likely that Congress would ever get around to updating the law anytime soon... does the FCC still even care? If a hardware manufacturer openly tried to sell a receiver that could tune to those frequencies, would they still be stopped?
- wolco2 6y agoI had a weird situation 12 years ago. I got a tv for christmas. When I set it up it scanned for channels. It picked up channels with decimals in the high range and there were pay movies on but when they finished the channel would go dead. The next day I rescanned the channels because of fuzzyness and it picked up new channels with decimals. This time some of the movies were x-rated. I would rescan daily usually in the evenings and watch what other people paided for. Thursdays and Fridays were good. During the day mostly kids movies. In the mornings someone would watch a porn fast forward 10 minutes to one specific part.. slow down the video to play 2 minutes then turn it off. Very funny. If you are in a building let your tv scan for channels in the evenings. If you see a decimal high channels you may have it too.
- rileymat2 6y agoI have seen the same thing. The most useful part is we could start an on demand show in the living room that had the only cable box, and find it in the bedroom.
- xchip 6y agoTL;DR: The Cellular Radiotelephone Service was allocated 824-849MHz and later 869-894MHz. That's it.
- OCISLY 6y agoThank you.
- ynniv 6y agoAnd yet you could dial TESTMODE on a StatTAC and listen to any analog channel. http://www.jax184.com/projects/StarTAC/wireless/testmode.html http://www.jax184.com/projects/StarTAC/wireless/testmode.htm...
- nezgar 6y agoHeh, I built that site as a StarTAC fan all those years ago, and Jax decided to preserve it when I donated the server hard drives and my box of startacs to him heh... the real limitation with testmode was there was really only about 4 channels you could choose to snoop on, but nonetheless there were still enough AMPS calls in 95-2000 in dense urban areas to be somewhat interesting... heard a couple of "juicy" conversations that also mentioned a phone number - was tempted to freak them out by calling it haha
- thrower123 6y agoI assume that frequency band is still reserved, even though it's not used for anything anymore?
- EricE 6y agoFor ever new regulation that someone wants to enact, they should be forced to take at least 10 out. 100 years from now we might get down to a meaningful mix of regs. Right now the Code of Federal Regulations (CFR) is like the roach motel - regs check in but never check out :p
- sellyme 6y agoAlternatively someone would enact a regulation, and then remove the regulation removal regulation as one of their ten.