An alternative: David Brin has proposed that cell phones should be capable of peer-to-peer text messaging when they can’t connect with a tower.
(My father, a professor of electrical engineering, says that this proposal would be technically difficult to implement because cell phones transmit and receive on different frequencies.)
It also runs into a public good problem, unless turning off the functionality is somehow made impossible. Battery life of cell phones is inconveniently short as it is, and the last thing people want is to spend even more energy on routing strangers’ messages. (If necessary, of course, they can turn it on just to send a message.)
Hams do this sort of thing already. If they could hook their G3 cell phone to a car battery and easily make it into a G3 APRS digipeater, they would do that too.
If the cell phone towers are down, maintaining a charge cell phone battery is near useless in current emergencies.
You need the distinct transmit/receive channels for full-duplex communication. The frequencies often only differ by <10MHz or so, with the uplink band being adjacent to the receiving band so they can share the same antenna an RF circuitry. The RF circuitry isn’t the technical difficulty, it’s in the software/firmware that is controlling the hardware. With some firmware/software changes, cell phones should be able to do some ham-APRS-like protocol.
The Hams have already solved this once using APRS at 144.39MHz, and it’s dumb that we don’t have a similar solution ported to cell phones at a convenient one of their working frequencies when not in reach of an on-line tower.
An alternative: David Brin has proposed that cell phones should be capable of peer-to-peer text messaging when they can’t connect with a tower.
(My father, a professor of electrical engineering, says that this proposal would be technically difficult to implement because cell phones transmit and receive on different frequencies.)
It also runs into a public good problem, unless turning off the functionality is somehow made impossible. Battery life of cell phones is inconveniently short as it is, and the last thing people want is to spend even more energy on routing strangers’ messages. (If necessary, of course, they can turn it on just to send a message.)
Hams do this sort of thing already. If they could hook their G3 cell phone to a car battery and easily make it into a G3 APRS digipeater, they would do that too.
If the cell phone towers are down, maintaining a charge cell phone battery is near useless in current emergencies.
You need the distinct transmit/receive channels for full-duplex communication. The frequencies often only differ by <10MHz or so, with the uplink band being adjacent to the receiving band so they can share the same antenna an RF circuitry. The RF circuitry isn’t the technical difficulty, it’s in the software/firmware that is controlling the hardware. With some firmware/software changes, cell phones should be able to do some ham-APRS-like protocol.
The Hams have already solved this once using APRS at 144.39MHz, and it’s dumb that we don’t have a similar solution ported to cell phones at a convenient one of their working frequencies when not in reach of an on-line tower.