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My biggest question is why fire departments are using consumer-level services over commercial-licensed radio bands when they could be using SDRs with the spectr

My biggest question is why fire departments are using consumer-level services over commercial-licensed radio bands when they could be using SDRs with the spectrum specifically allocated for land mobile communications for public safety and emergency services in the 1m to 10m VHF band?

thaumaturgy 8y ago
Well, it's complicated. The short answer is, "because nobody's come up with a better solution yet." Off the top of my head: In big incidents, there's a ton of radio traffic flying around at different frequencies. You have to make sure they don't interfere. Cellular handles this pretty well out-of-the-box. There are myriad electronics and devices in use, including wireless printers and laptops, so whatever you come up with has to play nice with wifi and also offer a wifi<->your_thing bridge. Again, cellular hotspots do this out of the box. Bandwidth is really important. GIS is a big part of operations, so that's a lot of high-resolution map tiles flying through the air, and when it takes time to load or print a map, it can really jam up operations. Seconds count. It needs to be maintainable by a large number of people. If there are just three people in the whole state who know how to troubleshoot and fix your system, it's no good. It can't be stupidly, ridiculously expensive. It has to work in all kinds of terrain. IC can't just squirt signals through hills. Somebody could probably invent a solution that does all those things. But they haven't yet.
- leni536 8y ago
  > Bandwidth is really important. GIS is a big part of operations, so that's a lot of high-resolution map tiles flying through the air, and when it takes time to load or print a map, it can really jam up operations. Seconds count. Is there a reason that map tiles have to be accessed real time over the Internet and can't be update for eg. daily and kept on a local hard drive? Is it too large? For a fire department it could be only the area that they operate in.
  - thaumaturgy 8y ago
    Mostly technical effort. I'm not sure what fire/OES uses for GIS. The system we use does have a locally-hosted option, but that requires someone knowing how to update it and what to do if the server stops behaving. > For a fire department it could be only the area that they operate in. Not really. Mutual aid happens often enough that that's not really a bet you want to make. Especially in the case of CalOES resources, which are sent from disaster to disaster all over the state.
    - leni536 8y ago
      > Not really. Mutual aid happens often enough that that's not really a bet you want to make. Well in that case it could fall back to Internet access, I guess. Just keep the map of the local area as cache.
mirimir 8y ago
It's probably because they need to deal with people who use cellphones. Including, I suspect, volunteers.
dfox 8y ago
Probably because they have some not-so-critical application that requires high bandwidth burst data (downloading tiled bitmap maps comes to mind), which is not something that you can do on VHF bands with currently available off the shelf technology (not to mention that the spectrum allocation certainly constrains emission types in such way that doing things like wideband MIMO COFDM and other high processing gain modulations is explicitly forbidden)

thaumaturgy 8y ago

Well, it's complicated. The short answer is, "because nobody's come up with a better solution yet." Off the top of my head: In big incidents, there's a ton of radio traffic flying around at different frequencies. You have to make sure they don't interfere. Cellular handles this pretty well out-of-the-box. There are myriad electronics and devices in use, including wireless printers and laptops, so whatever you come up with has to play nice with wifi and also offer a wifi<->your_thing bridge. Again, cellular hotspots do this out of the box. Bandwidth is really important. GIS is a big part of operations, so that's a lot of high-resolution map tiles flying through the air, and when it takes time to load or print a map, it can really jam up operations. Seconds count. It needs to be maintainable by a large number of people. If there are just three people in the whole state who know how to troubleshoot and fix your system, it's no good. It can't be stupidly, ridiculously expensive. It has to work in all kinds of terrain. IC can't just squirt signals through hills. Somebody could probably invent a solution that does all those things. But they haven't yet.

leni536 8y ago
> Bandwidth is really important. GIS is a big part of operations, so that's a lot of high-resolution map tiles flying through the air, and when it takes time to load or print a map, it can really jam up operations. Seconds count. Is there a reason that map tiles have to be accessed real time over the Internet and can't be update for eg. daily and kept on a local hard drive? Is it too large? For a fire department it could be only the area that they operate in.
- thaumaturgy 8y ago
  Mostly technical effort. I'm not sure what fire/OES uses for GIS. The system we use does have a locally-hosted option, but that requires someone knowing how to update it and what to do if the server stops behaving. > For a fire department it could be only the area that they operate in. Not really. Mutual aid happens often enough that that's not really a bet you want to make. Especially in the case of CalOES resources, which are sent from disaster to disaster all over the state.
  - leni536 8y ago
    > Not really. Mutual aid happens often enough that that's not really a bet you want to make. Well in that case it could fall back to Internet access, I guess. Just keep the map of the local area as cache.

mirimir 8y ago

It's probably because they need to deal with people who use cellphones. Including, I suspect, volunteers.

dfox 8y ago

Probably because they have some not-so-critical application that requires high bandwidth burst data (downloading tiled bitmap maps comes to mind), which is not something that you can do on VHF bands with currently available off the shelf technology (not to mention that the spectrum allocation certainly constrains emission types in such way that doing things like wideband MIMO COFDM and other high processing gain modulations is explicitly forbidden)