Future developments in the non-amateur world of radio from that point included cellular technology and the transmission of higher speed data over the air. Commercial applications for broadcast radio and television have changed radically and now include the imposition of digital methods. Military applications for secure battlefield communication use satellite and terrestrial means like mesh networking for voice and data transmission. Our homes, restaurants and coffee shops are bathed in RF transmitted data that keep our mobile devices connected to the Internet.Sure, there's the High Speed MultiMedia HSMM experiments... although the working group for that has disappeared and the general attitude I see about it, over and over is that you can do more with Part15 than you can with the higher power afforded with part97. It's a shame really. I've also seen a couple rare web pages discussing experiments with DATV. Much to my surprise, the experimenters preferred DVB-S to ATSC.
I'm not saying that Ham Radio is completely irrelevant. There's a lot of focus on it's use in emergencies and getting ready to help out in a disaster. And that's great. We have digital modes that run with a soundcard interface on a computer and software defined radio. There is a fairly basic digital voice mode called D-star. That's the big developments lately. Other than that, operating is fairly much the same as it was 30 plus odd years ago.
Why not a Ham Radio Cellphone network? I did some searching and this is what I've come up with..
Okay, the article discusses the use of this stuff to "hack" people's cellphone connections and listen in to their traffic. It misses a point that is blindingly obvious to me.
- European GSM cellphones have 900mhz as a band
- American Ham operators have 900mhz as a band
- Hardware exists to set up a homebrew cellphone base station
- How cool would it be to set up a legal ham radio cellphone network!
Imagine this: Your area sets up a Ham Cellphone node and various operators get a GSM quadband phone of their choice (probably needs to be unlocked). Now they can carry a form of communication around that allows them to contact other hams at any time. It will always work in an emergency. You could potentially allow for a "phone patch" operation. It would be beyond easy to put in an extension number to allow access to any attached repeaters, echolink, etc. Call ex# 270 to access the 147.270 repeater!
I wonder if the data connection works.. Hello hinternet! GSM-APRS? Text messaging? You could set up a truely cell based network with HSMM backhauls between each cell. Put the backhaul in the Ham allocation of 2.4ghz and have fun.
The OpenBTS project is what makes all of this possible. They use a software defined radio called the Universal Software Radio Project (USRP) along with their own Linux-based software to fully act as a Cellphone Base station. There is a blog written by the OpenBTS developers here.
Incidentally, The OpenBTS people have been running a small cellphone network at the Burning Man festival for the past 3 years or so. They get a special temporary license from the FCC and coordinate it with the phone company that covers (or doesn't, in this case) the area. The Wikipedia article references this but I can't find the blog posts that I remember where they talked in detail about it. This is the authorization for 2008 with temporary callsign WD9XKN.
Of course, after writing this whole thing I run across a Wikipedia page with GSM frequencies worldwide. Some of the allocations fall in the 900mhz band but it's not clear to me if there are any channels that fall completely into the 902-928mhz bandwidth that we are allotted. Can uplink and downlink frequencies be set to fall within the allotment? Will that actually work with any phones? I don't know.
Questions? Comments? Flames? Does anyone really read these things?