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Show HN: Sending and Receiving SMS via APRS (VHF Amateur Radio)
- jlturner 5y agoAlso supports optional message ack by placing ? after callsign. I’m looking to use this in the woods in case of emergency as you can forward your APRS message through one of the many digipeters available on mountain tops. Interested to hear of anyone has given this a try yet!
- mackmgg 5y agoIt supports an ACK, but unless you have a two-way i-gate nearby you should probably consider it to be a one-way protocol. All of the ones near me just go RF -> internet so there's no way to get a response back to RF unless you're running your own. Still useful for sending out quick status updates like "I'm doing fine but running late" but not good for full blown communication.
- twothamendment 5y agoExactly this. My wife knows not to panic if she can get my messages, but I don't reply to her. If any hams live in an area w/o a two-way i-gate, consider putting one up. It isn't that hard and provides a nice service.
- fishermichael 5y agoIt does work! I have called for help in a non-life threatening situation with no cell service by using APRS to SMSGTE while doing some off-roading. Even better, you don't even have to have a digipeater nearby. About once every 1.5 hours you can get a chance to send the packet via the ISS during a pass. SMS via space. :-)
- bitcoinmoney 5y agoHoly shit game changer. Finally time to dust off that ham license. Any tips on how to setup this ? Ideally I want a cheap handheld system I can send apfrs messages.
- jlturner 5y agoYeah you can use a cheap Baofeng radio (can get as low as $15-20), an “APRS cable” for it (about $20 on Amazon or make your own) which takes mic/ptt and audio out and feeds it to a 3.5” TRRS plug (think iOS / android headphones with mic plug), and an APRS app on your phone. Radio -> cable -> cellphone audio jack -> APRS app If you have an iOS device probably using a lightning / usb-c to 3.5” TRRS jack too.
- WrtCdEvrydy 5y agoWow, do you have a parts list on that cheap radio and APRS cable?
- jlturner 5y agoI’m using a Baofeng UV-5R (radio) and the APRS-K1 cable. I’ve linked Amazon pages but you can get them for slightly cheaper off eBay or AliExpress. Radio: https://www.amazon.com/Baofeng-UV-5R-136-174-400-480Mhz-1800mAh/dp/B074XPB313/ https://www.amazon.com/Baofeng-UV-5R-136-174-400-480Mhz-1800... Cable: https://www.amazon.com/BTECH-APRS-K1-Interface-APRSDroid-Compatible/dp/B01LMIBAZW/ https://www.amazon.com/BTECH-APRS-K1-Interface-APRSDroid-Com...
- twothamendment 5y ago"Radio -> cable -> cellphone audio jack -> APRS app" While this works, it is just the start. Soon you realize that you want to actually use your phone AND APRS at the same time and that your audio and mic are busy. I did this for about a day before seeking out something better. Radio -> cable -> Mobilinkd Bluetooth TNC paired to your phone -> APRS app Now you can take calls, play music in the car and drive down the road with a radio paired and use APRS. This isn't a bad setup, the big pro us the multitasking and using the APRS app on your phone to write messages. The other way I've done this is a radio that has the TNC and APRS built in. A handheld like the Kenwood TH-D74 can send and receive messages without any additional hardware, but you have to write the messages on a lame keypad like in the dumb phone days. I like this for backpacking as there are fewer pieces to worry about. It is fun stuff, and can be a life saver. Check out https://hamstudy.org/ https://hamstudy.org/ the easiest level (Tech.) is enough to get you access to all of this.
- lxe 5y agoThis has to be one of the most practical applications of amateur radio. Keep in mind that all of these comms are unencrypted and are visible by anyone who has the ability to receive.
- ronsor 5y agoSMS (especially traditional GSM SMS) is often unencrypted or poorly encrypted and visible by anyone.
- generalizations 5y agoYeah, but that was considered a problem and subsequently fixed.
- dicknuckle 5y agoCan't fix that in the context of HAM radio
- JshWright 5y agoAnd "the ability to receive" means "has a browser and internet access". https://aprs.fi/ https://aprs.fi/
- twothamendment 5y agoThese are visible not just by anyone who can receive, but pretty much everything on APRS ends up online. Most areas have an igate that forwards messages from the radio to the Internet. https://www.aprsdirect.com/center/40.55354,-104.97842/zoom/11/time/60/maptype/terrain https://www.aprsdirect.com/center/40.55354,-104.97842/zoom/1... is my favorite site for seeing what is going on in an area and where digipeaters and igates are. https://aprs.fi https://aprs.fi also works. Some areas have one that works in reverse, taking what is seen on the internet and relevant to the active stations in the area and broadcasting it out over radio. When I started using SMSGTE I had great success getting a SMS from my radio to a phone, but only 1 in 10 replies from SMS made it back to my radio. I put up a gateway for my area and so we have some decent bi-directional coverage.
- asow92 5y agoI'm starting to see a lot more interest in shortwave radio and radio in general recently. Is it just me being out of the loop or is anyone else noticing this?
- jah 5y agoMaybe it has to do with the start of solar cycle 25? Expect to see improving HF propagation over the next 3-5 years. It's an exciting time for radio nerds.
- genewitch 5y agoI've read that we're at sar minima until the most 2040s, so I'm not holding my breath for better propagation anytime soon.
- JshWright 5y agoBit of a nitpick, but the standard APRS frequency in North America is 144.390MHz, well above the "shortwave" bands (granted, it's still "radio in general").
- twothamendment 5y agoYeah... I hear shortwave and amateur radio (aka ham radio) used interchangeably all the time - but it isn't correct.
- asow92 5y agoa lot of folks (me included) have no idea what the differences are :)
- kube-system 5y agoShortwave refers to a band of frequencies with particular characteristics. Ham refers to radio bands allocated to amateur radio. There are shortwave frequencies that hams can’t operate on and there are frequencies outside of shortwave that amateurs can operate on.
- georgyo 5y agoAll these messages are of course completely public, and you can even get a full history of people using this service here: https://aprs.fi/?c=message&limit=50&call=SMSGTE https://aprs.fi/?c=message&limit=50&call=SMSGTE Very cool stuff.
- chrisseaton 5y agoBecause it’s a legal requirement to not encrypt the message?
- InvaderFizz 5y agoLegal requirement to not encrypt any Amateur Radio transmissions, yes.
- georgyo 5y agoNot actually enforced, and in some cases Amateur Radio transmissions are actually required to be encrypted: https://www.amateurradio.com/encryption-is-already-legal-its-the-intention-thats-not/ https://www.amateurradio.com/encryption-is-already-legal-its...
- genewitch 5y agoIf you have enough money you can build a system that is technically encrypted. See Fusion, d-star, and the other one I can't remember. What the FCC doesn't want is message passing that is not decryptable by them. They could care less if me or you can't decrypt fusion with an sdr. An interesting grey area is pactor. And not just for encryption, but also "symbol rate". If anything is going to bring ham radio into this century kicking and screaming it is stuff like aprs and pactor; and I say that knowing how awesome JT and wspr are.
- op00to 5y agoNo. Neither fusion, dstar, nor DMR use encryption. They are all publicly published modes.
- trasz 5y agoAPRS is cool, but it’s also somewhat… complex. I wonder how hard it would be to write a “modem chat” phone app, with the ability to translate text into audible Bell beeps, slow enough to work without cables, to be used over ordinary voice frequencies.
- genewitch 5y agoThere are apps that decode via phone microphone, most of the stuff that fldigi and radios can do out of the box (for example, rtty) It works well, and is bi directional, you can key a transmitter and hold its microphone to your phone speaker and transmit valid "digital" modes. Works fine, especially over repeaters, which annoys the old folks and the lids alike.
- op00to 5y agoLook up PSK31, RTTY.