The First Social Network: In rural Argentina residents send messages w AM radio

In the 70s and 80s (and probably before) in the UK, the BBC used to broadcast occasional "sos messages" [1] prior to the main daily news summaries on FM radio - for people who were away from home and, for whatever reason, uncontactable. They usually related to a relative being dangerously ill. I remember hearing them on my parent's car radio on summer camping trips.

Obviously the uk is a small and quite densely populated island but, without two way personal communications, some needs were similar to those described in the article. It changed a lot of things.

[1] https://swling.com/blog/2012/09/radio-4-and-now-an-urgent-so...

With a little investment, I think Meshtastic/Reticulum could do wonders for communities like this. With Argentina being largely flat, even putting up a relatively short mast on the roof of a house should give it a good enough range (~10-30km).

Can confirm that this is, effectively, a staple of normal life around there. Calling it "the first social network" made me chuckle.

Younger generations might not be aware of this mostly due to reduced AM radio audiences, but my daughters (3x ~30 yo) do know what this is about.

In that same occasion he also shared stories about doing amateur radio with his dad as a kid, which was what got him interested in tech and later led to him becoming an entrepreneur

Through the efforts of many (and yet still few) we have created such amazing technologies. And yet so many are still so poor and without the benefits of modern technology because we've allowed a system (capitalism) to be created where wealth and access to technology accumulates up top and no, it does not really "trickle down".

To me, it really is the saddest thing about human existence and entirely predictable because of how most of our human behaviours are linked to evolutionary processes.

It's nice to romanticise human emotion and connection in a rugged environment using technology that we consider defunct and for them to be able to live a life that many would consider "more natural". But then one of them gets sick. Someone who loves, is loved, who creates art and consumes art, who smiles when the petrichor hits their nostrils after a dry Summer. And then they die.

I just really wish that things were more equitable because we definitely have enough to go around.

https://theprisonshow.net/

(ETA: Ah, missed reaperducer beat me to it)

KPFT's version is a little more specialized. It's called The Prison Show and transmits messages from families to their loved ones behind bars.

When I'm in Houston, I try to listen because it gives you a taste of a segment of life and people you may otherwise never come in contact with. If you're interested in human nature and the power of communication, it's very engaging.

The last time I heard it, it was on in the evening, I think on a weekend.

    For Armando Nahuelquir—his wife, Casilda, communicates to him that she is travelling to the campo and will arrive today.
    Inosencio Belisle, in Chubut, is advised that his brother Baldobino is sick and hospitalized in General Roca.  11 4867 5309 if he would like to communicate . . . with his niece Malvina.
    Attention Gómez Roca—we’re waiting for you in Puerto Deseado.
    For Jorge Sepúlveda in Cajón de Ginebra: Paternoster asks that he get in touch today as soon as possible, at the same number as always.
    For Jorge Crespo: Ricardo says that tomorrow, Tuesday, he will pass by his house.
    For Emmanuel Ortega, wherever he is: his sister María wishes him a very happy birthday. She cares about him very much.
    For Nicolás López, in Estancia La Elenita: his nephew Martín communicates that the four-wheel drive of the van is broken.
    For Enrique Vega, in Telsen: his mother wishes him a very happy birthday. Over here, everyone is well.
    Two years and five months since the irreparable physical loss of Fabio Ezequiel Leslie. His parents and siblings miss him and remember him with as much love as the first day. Praying for his eternal rest.
    Avelino Delgado, of Establecimiento El Calafate, in the region of El Escorial, has lost a Hereford bull. If someone sees it, please notify him on this same channel.
    For Jorge Pereyra, wherever he is: Jordan Salama, the American he met at Estancia La Adela, in Caleta Valdés, communicates that he wants to find him, if it’s possible to get in touch with the radio station. Whoever hears this, please let him know.

To transmit over the horizon as the AM stations do, you'd have to use similar frequencies: the mediumwave frequencies they do in fact use, or shortwave, which would permit the use of less unwieldy transmitting antennas.

So the basic setup would be: you still broadcast all the messages from a single high-powered sender, but you have some kind of analog radio receiver frontend running night and day on, say, 250 milliwatts, with a ferrite loopstick antenna like an AM radio uses. It's connected to, say, an STM32F103 (US$1.84, although here in Argentina a Blue Pill costs more like US$12 and probably comes with a clone chip with somewhat poorer analog characteristics) running at 72MHz, sampling the incoming signal at 1Msps and attempting to decode bits from it, referencing its timing to a ±50ppm quartz crystal.

The STM32F103x8/STM32F103xB dadashit tells me it uses a maximum of 50mA at 3.3 volts, so that's another 150 milliwatts. So this is a setup that probably needs about 0.4 watts, 9.6 watt hours per day, or 3000 milliamp hours per day; if you're receiving 24/7, you probably don't want to try to run it off non-rechargeable batteries the way you do with an AM radio, but a small solar panel and an 18650 rechargeable cell should be fine.

Or you could use crude time-domain multiplexing: power your receiver up, say, twice an hour for a second or two, at a time that the transmitter knows your receiver will be listening, and power back down if there's no message for you.

But it would be desirable to also transmit; it allows you to answer those messages without traveling those 80 kilometers to the post office. To get AM-radio sound quality good enough for people to understand speech, you need several thousand bits per second of channel capacity (4kHz at 10dB SNR into C = B lg(1 + S/N) gives us 13800 bits per second), and, roughly speaking, several thousand times more transmission power. https://www.lu4aa.org/wp/wp-content/uploads/2020/11/LISTADO-... tells us that LU-20 Radio Chubut, one of the radio stations participating in this practice, transmits at "25/5" kilowatts, which I think means 25 kilowatts by day, 5 kilowatts by night (that's what the same notation means in the LU-4 row, according to https://es.wikipedia.org/wiki/LU4_Radio_Nacional_Patagonia_A....)

If 2 bits per second is enough, you can probably get by with transmitting at 6000 times lower power, which is about 5 watts, or 1 watt at night. Decentralizing transmission incentivizes the use of higher frequencies, because they can use smaller antennas. At the extreme of 30MHz, a quarter-wave groundplane antenna only has to be 2.5 meters tall, and erecting even a 7.5-meter tower antenna seems eminently feasible to do on a shoestring rural sheep-herding estancia budget, since you don't have to deal with an HOA. And, if people are willing to cooperate to relay messages (a "mesh network", although the older term might be "radio relay league"), you can use lower power and get higher bandwidth.

The only part of this that would be news to radioaficionados decades ago is the radically lower price and low power of complex modulation schemes, due to cheap microcontrollers.

This is, of course, what Rhizomatica, Hermes, and MeshArg are trying to achieve, although MeshArg is using higher frequencies that are not suitable for long-distance communication unless you have a satellite or balloon or something.