SDRTrunk Increasing SDR Reception?

[KI5IRE]

Is there anything I can do to increase the reception of an SDR, specifically using SDR Trunk?

I am attempting to setup two of my RTL-SDR dongles on SDR Trunk to stream a P25 system near me to the calls platform, but SDR Trunk is not seeing the system.

I am able to get a good lock on the control channel and even decode control channel data in Pro96Com using a Uniden 996XT, but when I connect the same antenna to my SDR dongles, it won't lock on the control channel using SDR Trunk.

This specific system is the Broken Arrow Communications Regional Network (BACRN) in the Tulsa, OK area. I am only 5-10 miles from the main site which if the Broken Arrow site, which is a four-site simulcast site and am well within reception range.

Any ideas what I can do to possibly receive the system on my SDRs?

 

[Bustergrn]

I've had issues with SDRTrunk continually decoding neighboring TRS OKWIN. Loses the CC after a few minutes and then it's intermittent. I switched to OP25 and all is well.

Also, a good portion of that system is encrypted. Almost all of City of BA, Bixby, Glenpool....I think Jenks and Wagoner County are the only one's in the clear.

What type of antenna are you using?

 

[KI5IRE]

I've had issues with SDRTrunk continually decoding neighboring TRS OKWIN. Loses the CC after a few minutes and then it's intermittent. I switched to OP25 and all is well.

I have not messed with OP25. I am running an old Windows PC and trying not to have to purchase Raspberry Pi for this task if possible.

Also, a good portion of that system is encrypted. Almost all of City of BA, Bixby, Glenpool....I think Jenks and Wagoner County are the only one's in the clear.

From what I've found with listening on my SDS100 and Pro96Com logs, BA is mostly encrypted, PD is sporadic sometimes, FD is always encrypted. Bixby PD is mostly encrypted, dispatch console sometimes in the clear, Bixby fire is mostly in the clear. Glenpool Police and Fire are encrypted most of the time as well. Jenks Police and Fire and mostly in the clear. Wagoner Co. is also mostly in the clear, besides Wagoner PD. And Rogers County/Claremore may be moving to this system.

There is also sporadic temporary patches that go on (if you're familiar with Harris systems you've likely seen this before) and you can sometimes hear Glenpool FD dispatched in the clear. I think this is for runs with TFD...could be a patch group though for interop, haven't looked to see if it's always the same TGID or not. That being said, there is enough activity on this system IMO worth streaming to BCFY calls.

What type of antenna are you using?

I'm mostly using a Wilson Electronics 311125 Dual-Band Magnet Mount Antenna 800/1900 MHz Omni Directional that has 6 dB of gain.

Occasionally I'll use the antenna that came with my RTL-SDR configured as either a dipole or a directional antenna.

All of this is from the second floor of an apartment building in Midtown near 15th and Utica.

 

[lwvmobile]

Might be worthwhile to turn the gain down on the dongle, instead of leaving it on the default settings. What does the waterfall look like?

 

[maus92]

SDRTrunk is fairly resource intensive - how "old" is the old PC? I would try starting with only one SDR connected, making sure an appropriate ppm correction is dialed in manually, and adjust that correction as necessary. There's nothing particularly esoteric in setting up SDRTrunk other than compiling the Java library for the installation. Once you get the control channel dongle working, add the second to cover the traffic channels.

 

[PDXh0b0]

couple diy 1/4 wave ground plane antennas preform like champs

 

[squall8ball]

i have a few suggestions, one thing you can try right away is go to playlist editor- channels- and select what ever system your attempting to tune a bit and scroll to the bottom and select LMS. If its on C4FM it will have a really hard time decoding simulcast broadcasts while your that close to the towers.

 

[KI5IRE]

Might be worthwhile to turn the gain down on the dongle, instead of leaving it on the default settings. What does the waterfall look like?

I don't believe there is a way to do this on the RTL-SDR, unless theres settings somwhere in SDR-Trunk?

SDRTrunk is fairly resource intensive - how "old" is the old PC? I would try starting with only one SDR connected, making sure an appropriate ppm correction is dialed in manually, and adjust that correction as necessary. There's nothing particularly esoteric in setting up SDRTrunk other than compiling the Java library for the installation. Once you get the control channel dongle working, add the second to cover the traffic channels.

It's not a matter of resources in this case. Other systems decode fine on this computer. This is a matter both on my Mac which is nearly spec'd out and my PC.

i have a few suggestions, one thing you can try right away is go to playlist editor- channels- and select what ever system your attempting to tune a bit and scroll to the bottom and select LMS. If its on C4FM it will have a really hard time decoding simulcast broadcasts while your that close to the towers.

It's a Phase II system so it's not giving me this option. Is there another way to do this?

 

[maus92]

Clearly there is an option for LSM on Phase 2 - this is a Phase 2 system, and in the Decoder section you can select between C4FM and LSM. I'm not saying that this is your problem specifically, but I am sure your issue is a configuration or hardware problem.

 

[KI5IRE]

View attachment 113924

Clearly there is an option for LSM on Phase 2 - this is a Phase 2 system, and in the Decoder section you can select between C4FM and LSM. I'm not saying that this is your problem specifically, but I am sure your issue is a configuration or hardware problem.

If you enter the system from the radio reference database, it imports it as a P25 phase 2 system which does not show that option. I entered the system manually into SDR-Trunk and then it showed up like what you were showing. But that did not help either.

 

[maus92]

If you enter the system from the radio reference database, it imports it as a P25 phase 2 system which does not show that option. I entered the system manually into SDR-Trunk and then it showed up like what you were showing. But that did not help either.

Interesting, but I did import system using the RRDB and you can see what resulted. Except for the very newest Phase 2 systems, the control channel is 12.5 FDMA so it doesn't really matter. Many systems that are marked as Phase 2 systems in the RRDB are operating as Phase 1 systems btw - or mixed FDMA / TDMA.

The next question is have you corrected your SDR(s) for ppm? You did not answer that question. I'm assuming that you did not forget the step to install Java from within the program.

 

[maus92]

Both gains and ppm can be adjusted in the Tuners page, lower right corner. See below: