Hi,
My PC died on me on friday, so no C-development or mailing list discussions this weekend. Well, it can’t all be about D-STAR and digital voice, and it gives me a little time to play with this: a sparkfun si4735 FM/AM receiver arduino shield. continue reading…
Hi,
I’ve pushed an updated of the gmsk software on github. It can be found on its usual address: http://github.com/on1arf. The GMSK sender is now version alpha2. The last release of the receiver is version beta2.
Overall, four things where added:
With the codec2 vocoder becoming more and powerfull, the possibility of a ham-radio VHF/UHF Digital Voice system using that voice codec is an issue that pops up on different mailing-lists from time to time.
On the codec2 mailing-list on sourceforge, an interesting question emerged: if a new GMSK-based ham digital-voice system would be introduced on VHF or UHF, there is a big change that some day, both systems would be used on the same frequency. As codec2 and AMBE -the vocoder used by D-STAR- are completely incompatible, would this not lead to fellow hams getting lots of R2D2 on their D-STAR radio.
Concidering that D-STAR radios have fixed firmware that cannot be changed, how do we make sure that the two systems do not interfere with eachother?
Or, … how does a D-STAR radio react when receiving a non-D-STAR GMSK stream?
Using the new “gmsk-sender” application (see earlier blog message) which is able to generate any kind of GMSK-stream, I descided to give this a try.
The last weeks and days, I have pushed three software updates on github. As usual, the source-code can be found on https://github.com/on1ARF
The GSM receiver has moved up from “alpha” to “beta” phase as it has achieved a certain level of stability.
It may sound hard to believe but, these days, writing a GMSK receiver is in principe not that hard. All you need to do are these for 4 steps:
The end result: a .dvtool file containing a D-STAR stream.
Easy no? 
Hi,
After a discussion on HF digital voice and the AOR ARD9000 modem in the “digitalradio” group on googlegroups I descided to do a little bit of research on this mode.
According this information on hamuniverse, this modem is based on a “open” standard, developed by Charles, G4GUO, but the specification itself turned out to be more difficult to locate. So I contacted him for more information.
This is the information that emerged from the following email conversation:
As Charles is now mainly working on ATV (check out his blog) and has no time anymore to work on this, I got permission from him to republish the original specification.
You can find it the document here.
Charles as has also provided source-code of a modem to implement this protocol (assembler code for the motorolla 56K DSP CPU), which may be redistributed as open source.
However, a small part of the code is covered by a copyright of a 3th party. To be sure that no Intellectual Property issues will arrize in a later stage, this issue needs to be “cleared up” beforehand. If needed, that small part of code (Fast Fourier Transform) will be excluded.
73
Kristoff – ON1ARF
A couple of weeks ago, I started a small project to experiment with using a ARM development board as GMSK modem, the basis for any D-STAR system. Using a simple FM tranceiver with a “9k6″ data port and a USB sound-dongle, these boards can be used to receive a D-STAR compatible GMSK signal. Transmitting a GMSK signal will be added later.
At this time of writing, there is “alpha” code running that turns these boards into a D-STAR receiver and write the received data to a file. (see photo below):
This article is the first in a series that describes the software and hardware developements in this project.
Hi,
Ken, KE2N, has rapported that the URLs for the audio-files of the NOAA US weather rapports have been changed without notice.
They can now be found here: http://www.erh.noaa.gov/lwx/podcasts/mp3/
An example of a script that plays out the WX-rapport for the Washington DC metro areas is:
date >> /root/voice/wx1log
/usr/bin/./mplayer -really-quiet -vc null -vo null -srate 8000 -af channels=1 -ao pcm:file=/dev/stdout http://www.erh.noaa.gov/lwx/podcasts/mp3/WBCSAFNW1.mp3 | ./wavstream -t “WX RPT” -v -i 192.168.1.111 -p 40000 W4BRM b /dev/stdin id.wav 2>&1 | head -1000 >> wx1log
Thanks to Ken for the new links.
73
Kristoff ON1ARF
Hi,
We have started a experimental internet-stream of module B of the D-STAR repeater in Oostende, ON0OS. This is a first test of the “D-STAR Audio Export Toolkit” (tempory name). The URL are:
)This stream is created inside the repeater using a DVdongle connected to the repeater. No D-STAR “radio” is involved. continue reading…
Hi All,
I have just posted version 0.2.1 of the voice-announcement software for Icom-based D-STAR repeaters.
As usual, it can be found here:
http://villazeebries.krbonne.net/dstar/voice-announce/
This version has been designed with one application in mind: streaming long audio-broadcasts to repeaters. Here are the details:
