8 Jan
2018
8 Jan
'18
2:43 a.m.
The constellation just shows that you have a stable signal being decoded, not WHAT the
data stream contains. In an ideal world you'd just see four tight clusters of data in
the four corners of a square regardless of whether you are decoding a control channel or
voice. In practice you may see some slight disturbances and spread of the pattern into an
X shape. You may also notice momentary rotation of the pattern due to phase shifts, but
these will (usually) go away as the gardner_costas loop adjusts itself.
There are potentially numerous reasons for not hearing voice, but incorrect command line
parameters are the most common. Make sure you have "-V", "-2" and
"-U" specified. When a tgid is tuned, you should see an indication at the
bottom of the terminal screen showing the frequency and optional (phase 2 only) slot
number as well as the tgid and tag (if available). If you're not seeing that,
it's not attempting to decode audio.
if you are running my version of the code (github.com/boatbod/op25) you have the option to
suppress encrypted audio using the "--nocrypt" command line parameter. In this
instance you should see indication on the terminal screen (bottom right) when encrypted
audio is being suppressed. On Max's version of the code, encrypted audio will be
played and just sounds like garbage noise.
Install is most easily carried out using the ~/op25/install.sh script once you have
cloned your repo of choice.
Graham
---In op25-dev(a)yahoogroups.com, <bwmzzzx@...> wrote :
I finally had time to install new Ubuntu 14 load and op25 and it started working, I
think. I used the constelation window to determine if I was receiving a p25 transmission
but no sound. I finally found out that not all constelations mean sound?? Which brings me
to a question. What is heard or seen on the windows during an encrypted transmission? If
it's the same type of constelation diagram but no sound then it's working. I then
put my old P25 phase 1 scanner running alongside my op25 to see if I was getting the same
transmissions and it appears there is a little bit of difference. I guess they haven't
completly gone to phase 2 yet. One more quick question, do the installation instructions
given back by Bill still hold true for this new version of op25? Hoping all had a Merry
Christmas and Happy New Year too.....