At 11:34 PM 6/8/2010, you wrote:
>So my question is, how long has the G3RUH modem and other CODECs >been around that could make a VHF/UHF communications system like >D-STAR. From my knowledge, the solution has been available for >probably 5+, if not 10+ years. But yet the glorious "Amateur Radio >Experimentation" hasn't come up with a solution that used it. I'd say 10+ years. The reason I say this is: 1. The G3RUH modem was around over 20 years ago, though it was harder getting one on the air than it is now (more radios with suitable interfaces brought out to a connector nowadays). 2. Speak Freely (which IRLP is heavily based on, and Echolink is a more distant cousin of) has had open source implementations of LPC, LPC-10 and CELP (4800 bps), all of which could easily be carried over 9600bps. I was running Speak Freely in 1995 over 14.4k dialup. >What we need is something like the ability to place hot spots all >over the place and the hot spots interoperate and are connected to >the Internet (as well as other possibilities) and are smart enough >to handle handoffs from other hotspots as you move around. And then >the radios are probably similar to today's D-STAR radios, but able >to handle the handoffs and can provide 4.8, even 9.6 bps error >protected data transfer. Hmm, a low speed voice data network, meshed by a mixture of Internet based and RF based high speed backhaul links? That could be interesting. > >Forget about duplexers and use 440 in and 1.2GHz out. That would simplify the engineering considerably! All we need is cost effective 1.2 GHz radio hardware (440 will be a piece of cake). 10m/6m 4800bps nodes would be interesting to play with as well. 73 de VK3JED / VK3IRL http://vkradio.com
