VHF pagers were the last way you could recieve notifications without having to offer up your location to surveillance. All satellite pagers require transmit-before-receive, and of course LTE requires that plus actively cooperating with the towers' triangulation of the receiver.
VHF POCSAG over large urban areas is something we never should have let go of.
I know of it being used for fairly mundane things like Grafana Alerts (or the equivalent), but in circumstances where you need to reach people in areas where cellphones are forbidden or lack coverage (like security sensitive data centers for example).
Snooping on that frequency band in ≈Stockholm it also seems to be quite actively used for sending machine-to-machine commands in some industries, perhaps not always that stringently authenticated...
Which I guess is a downside though, you need to take proper precautions in the "application layer" since the network is completely open.
https://www.unication.com/alpha-pagers
And here's LRS's implementation of encryption on POCSAG:
I'm not a ham, because I don't want to hang out with self-appointed cops, so I got a new Chinese pager made up with a center frequency of 433.5MHz (ISM, unlicensed), then configured it to work with a Pi-Star rig radiating well under the EU/Irish legal power limit, and receive messages infrequently enough not to run afoul of duty cycle limits. Because I know there's some ham who's just salivating to track me down and quote the rule book to me, and I want to deny him (it's always a him) that pleasure. It reaches all the way to the far end of my farm!
You can get traditional alphanumeric belt loop pagers or snazzy modern wristwatch pages these days. Check AliExpress.
Hams do have a "Whacker" problem. General Boomer mentality scares away a lot of new Hams as well.
Ps there is still the iridium paging service which is one way and is not transmit before receive. But they want to get rid of it and stopped selling hardware. It's really hard to find now second hand.
I had one and I've only been outside the coverage area once, when I went on cave trip. I noticed my pager said OUTRANGE which was something I had never seen any other time. The coverage really was phenomenal due to the low frequency (159Mhz).
The only thing you can receive without transmitting is a one-bit "message waiting" indicator, so you don't waste uplink bandwidth polling the satellite unless there's something there for you. Basically the satellite broadcasts a list of terminals that have messages waiting for them. I recall there being some kind of bloom filter, so technically it's less than one bit.
You can't get anything else downstream unless you transmit first to ask for it. Also the only way to clear the "message waiting" bit is by transmitting to the satellite, so you can't even try to encode a message by flipping that bit on and off.
You had to manually update your paging location by dialing some number or by using a web interface when moving significantly, or link an Iridium phone to your pager, which would then automatically update the paging area (MDA) every time you made a call.
What you mean is probably Iridium SBD, but that’s a different, bidirectional service (also used for pager-like devices these days).
I did not know about Global Data Burst; I think that's what you're referring to. Holy cow it's expensive though, although I guess it has to be since you're using a lot more bandwidth*footprint. Like $6.00 per message per delivery area expensive. And they're kinda vague on how big a "delivery area" is.
GDB seems to be a successor to that, though.
Iridium Burst seems to be multicast-capable, and optionally bidirectional or unidirectional, so "spicier SBD" makes sense!
But their paging service was definitely unidirectional and unicast. Here's an old talk on decoding the signal, if you're curious: https://media.ccc.de/v/31c3_-_6236_-_en_-_saal_1_-_201412281...
...and instead anyone in your city can read every single text message with a trivial amount of hardware?
You can even buy two-way pagers that transmit with AES-128 encryption. Hospitals have to use this due to HIPAA:
https://www.spok.com/blog/standard-or-encrypted-pagers-whats...
I think you're confusing commercial pager services with Ham radio.