9 Jun
2017
9 Jun
'17
4:57 p.m.
Thanks for the quick replies. Attached are:
1. trunk.tsv and the local talkgroup list montgomery.tsv
2. Screenshot of the console after starting, using -v 255.
3. Screenshots of spectrum, datascope, constellation, and traffic.
Here is the command line I'm using:
./scope.py --args 'rtl' -f 853.5e6 -N 'LNA:35' -o 17e3 -V -v 255 -S
2480000 -q 0 -T trunk.tsv
My RTL-SDR.com dongle seems to be just about on frequency; it has a
TCXO. I've messed with PPM correction as well as fine tuning and,
though I'm not sure just what I should be looking for, changing those in
either direction tends to result in tuning error messages.
I am not sure if Montgomery County is C4FM or CQPSK. Radio Reference
seems to indicate C4FM; I've mainly used that, but tried CQPSK a couple
of times with no "traffic" shown in either case.
Thanks!
John
----
On 06/09/2017 09:44 AM, 'wa8wg' wa8wg(a)centurytel.net [op25-dev] wrote:
John,
You should normally get an error message when starting scope.py if your
trunk.tsv if your trunking system occupies more bandwidth than is
supported by the sample rate capability of your SDR. Maybe you could
post your trunk.tsv for a look see? However, it sounds like your
constellation doesn’t look the best. Is scope showing the P25 frames
being decoded and does it indicate any errors on those frames? I have
my op25/GNU Radio running on Ubuntu 14.04 virtualized in Oracle
VIrtualBox on my Windows 10 laptop.
Bill, WA8WG
William G. Becks, WA8WG
N7027 Shady Lane Circle
Porterfield, WI 54159
Telephone: 715.735.0131
E-Mail: wa8wg(a)centurytel.net <mailto:wa8wg@centurytel.net>
*From:*op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com]
*Sent:* Friday, June 9, 2017 7:28 AM
*To:* op25-dev(a)yahoogroups.com
*Subject:* [op25-dev] OP25 setup once built
Hi --
After looking at the archives, I think I may need to use a different
software branch, but here's where I stand:
1. Downloaded OP25 from the oscomcom site.
2. Built without any problems on Mint 17.04 with Gnuradio 3.7.11.
Computer is an i7 laptop with 8GB RAM. I'm using an RTL-SDR dongle for
now; I can try a USRP but wanted to start with the simpler hardware.
3. Cobbled up .tsv files for local P25 system (Ohio MARCS-IP,
Montgomery County site, C4FM). This site has 30 channels and the 2.4
msps rate of the dongle can't catch them all, but I am covering the
control channel pllus several more channels.
4. Scope.py seems to run fine with all windows looking proper.
Selecting some tabs causes timeout errors on the console, but those stop
when I switch tabs..
5. I seem to be tuned to the control channel (853.600) and see a
not-terrible constellation.
6. But I don't see any traffic decoding, much less get any audio (I
know that the 30 channels at this site are spread over a bandwidth
greater than the RTL-SDR dongle can provide; I can bring a USRP to the
game but for now would be happy just to decode control data.
I'd appreciate any help, particularly on what the scope.py command line
should look like. And should I be using a version other than what is on
the Osmocom site?
Thanks much,
John Ackermann N8UR
jra(a)febo.com <mailto:jra@febo.com>