> Mobile CB
It's actually ridiculous that our phones support dozens of sophisticated radio protocols but can't act as two way radios without a cell tower from the right company nearby. A $10 walkie talkie can communicate over miles but your phone is a brick without service. This capability would save more lives than Apple's satellite SOS IMO.
They don’t really have the right frequencies available. In the GHz range they operate point to point comms at ground level with low powered radios wouldn’t be a great experience except for if you were so close to someone you could practically shout at them.
Amateur Radio and GMRS though are still very much things that will give good performance for those use cases. GMRS requires a “license” but no skill is required, just payment to the FCC.
Ham radio or GMRS are still great options for remote areas or at crowded venues where nobody can get cell service because everything is overloaded.
The frequencies that walkie-talkies use are available for walkie-talkie use. Sure, it might need another antenna, but so do features like mmWave, UWB, and Satellite SOS, and I guarantee a genuine walkie-talkie feature would see more usage than those. iPhones already contain antennas for dozens of bands including 600 MHz. I don't see it being infeasible to add ~465 MHz band support.
Unihertz even makes an Android phone with a DMR UHF transceiver, the Atom XL.
https://www.unihertz.com/products/atom-xl
Ignoring the frequencies for a moment, because physics, the phone does 'wi-fi' calling just fine, a 40 'channel' (or 'room') push to talk (or VOX) voice app is pretty trivial. You get close just running the discord client on your phone. That _does_ require WiFi, but _doesn't_ require a cell tower. So modally, totally doable from a WiFi network, if your making your own WiFi network then yeah, you need a cell tower.
There are a lot of things our phones are capable of that we are not able to get them to do.
Even before the iPhone I had a phone with front and rear cameras and Bluetooth, it has long since been replaced and is probably sitting at the back of a drawer somewhere. If I had the ability to make it work as a Bluetooth webcam it might have had a productive second life. It was physically capable of doing this, just not software capable
The latency and bandwidth on BT does not suffice for today's expected webcam level quality.
FWIW you can use an Android phone as a web cam. Not sure what the latency is though...
Yes but this was pre iPhone days. It was not going to be doing today's expected webcam level quality no matter which way you sliced it.
Walkie talkies require a lot more power than smartphones have. FRS is 2W, ham radio handhelds are usually 5W, smartphone Wifi is 30mW. They also require a long antenna sticking out the top. Smartphones have UHF range antennas so possible to fit them but won't be as good.
What is disappointing is that LTE Direct and 5G Peer to Peer didn't go anywhere. They do LTE or 5G directly without towers. The range is 1km, not walkie talkie distance, but enough for a lot of things. There are some first responders phones with but it doesn't seem to be available for public.
> Walkie talkies require a lot more power than smartphones have.
Yes and no. "Real" handhelds could broadcast at 5W but the Walkie Talkies that Radio Shack sold[1] were in the unlicensed band and limited to 10000 uV/m which is well within capabilities of a current cell phone power wise, as you note this would not be efficient with their antenna arrangement :-)
That said, it would be fairly trivial to use websockets to create a "PTT Walkie Talkie app" (think 2 person zoom meeting with no video)
[1] Exemplar Realistic TC-500 page 56 of this 1991 catalog: https://www.radioshackcatalogs.com/flipbook/1991_radioshack_...
Bitchat might interest you. It just uses Bluetooth for a local mesh.