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opensource imbe encoder
Posted: Tue Dec 01, 2009 12:05 pm
by gopher
Re: opensource imbe encoder
Posted: Tue Dec 01, 2009 7:41 pm
by gopher
since this got tucked away in a dark corner...
if anyone is interested in this setup check out op25
http://sedition.org.au/op25/ work continues on this project, expect to see a repeater setup soon.
hard ware used is a usrp1
http://www.ettus.com/ which will set you back 700 big ones, plus rf boards...
my only tx board works in the 900mhz range but there was supposedly to be a 50mhz -1ghz transceiver, however it went vaporware...
the gnuradio toolkit is used for interfacing to the radio.
SDR is here to stay, it is the future of all radio communicatons
Re: opensource imbe encoder
Posted: Tue Dec 01, 2009 11:21 pm
by MattSR
Im currently using OP25 with a TVRX. Need to get a RFX400 so I can test Max's repeater code.
I also emailed him and got him to check in the soundcard transmit code today too so I need to get that done ASAP is it will negate the need for a USRP
Re: opensource imbe encoder
Posted: Wed Dec 02, 2009 12:54 am
by gopher
cool let us know how it works.
i am surprised the range i got with just a 150mw signal. using a small diamond SRH805 HT Antenna mounted directly on the usrp on the 2nd floor of my house i was able to receive clear digital 300 feet down the stree in an urban neighborhood. not bad!
Re: opensource imbe encoder
Posted: Wed Dec 02, 2009 4:59 am
by Wowbagger
Are you sure the vocoder itself is open source? I watched the video, he said "P25 encoder" - which could refer to the vocoder, or to the rest of the framer/dibit coder/pulse shaping/modulation chain.
DVSI are VERY protective of their patents. Yes, you could, in theory, reverse engineer the IMBE vocoder from the patents + examination of the vocoded data stream, and create a piece of software that was GPL and implemented that algorithm. However, such a library would violate DVSI's patents, and would be absolute DEATH to use in any project where there was enough money to sue over.
Also, last I'd heard, everybody was using the DVSI USB dongles to do the vocoding - which means the vocoder isn't Free.
I'd like to hear more about this.
Re: opensource imbe encoder
Posted: Wed Dec 02, 2009 1:33 pm
by gopher
all code used in the test program is open C++ including the imbe vocoder
Re: opensource imbe encoder
Posted: Fri Feb 12, 2010 8:07 pm
by MattSR
gopher wrote:supposedly to be a 50mhz -1ghz transceiver, however it went vaporware...
Ettus released this as the WBX - and they extended the range to 50mhz-2.2Ghz.