Adding a new P25 system to fastlane.

[merlin]

I added a new system to my fastlane, a neighbor system to an existing system. All looks and works good except the voice on this system is badly garbled. At least with my bad hearing, it is unintelligible.
Are there any tweaks I might do to improve this ?
TNX 73s

 

[Tom_Neverwinter]

Antenna tuning. set proper length and angle for required frequency.

install a lna. be careful not to overpower the sdr though. for instance an FM channel should not require a LNA to receive.

 

[maus92]

Could be any number of issues. Specifics of your circumstances - like the system in question, your fairly exact location, and your equipment would be the basis for further recommendations.

 

[merlin]

Antenna tuning. set proper length and angle for required frequency.

install a lna. be careful not to overpower the sdr though. for instance an FM channel should not require a LNA to receive.

Discone with 55' LMR400 into a preselector then to the SDR. I show a +30DB S/N. frequency error less than 15Hz.
The stream shows practically no errors. This is a one dongle setup so I do expect drops when it reverts to the CC .
It is a fairly quiet 4 channel system and usually 2 active channels during a call.
If I get SelCall tones, even they are broken up a bit. I looked for something overdriven, but nothing.
TNX

 

[merlin]

Could be any number of issues. Specifics of your circumstances - like the system in question, your fairly exact location, and your equipment would be the basis for further recommendations.

The repeater is 28 miles and line of sight. My thinking was sampling rates too fast or slow, but that seems optimized well. I tweaked the front end for best signal/noise ratio so this seems unprecedented.
A neighbor site that is far more busy is more broken up but what audio I get is at least intelligible.
TNX
PS: Funny I shot this after getting my antenna back up. The repeater site is just above that far tree line on a peak about exactly in line with the photo. (eyeshot tower to antenna.)

 

[wgbecks]

If you're getting a fairly decent CC decode then it stands to reason the service channels should as well. Are there any service (voice) channels on the distant site that my fall outside of the bandwidth of whatever preselector you're using? You might try bypassing the preselector and provided
that it's not needed to prevent some local signals from overloading your SDR.

If bypassing the preselector isn't helpful, then I have means to analyze the composite IQ signal that can be captured as an .IQ file using the
(R) record function available from FMP24/FMPA/FMPP. Note, this has to be an IQ capture and not a wav format file that's typically done from
DSDPLus FL.

The .IQ dumps are quite large and grow quickly in size the longer your record making it necessary to post the file(s) via a cloud drive
service that can be shared with others.

 

[mtindor]

I added a new system to my fastlane, a neighbor system to an existing system. All looks and works good except the voice on this system is badly garbled. At least with my bad hearing, it is unintelligible.
Are there any tweaks I might do to improve this ?
TNX 73s

Any chance you can be more specific, by providing an RRDB database link to the exact system you are monitoring, along with a mention of the particular site?

Are you running FMP24/FMPA/FMPP --> Direct Link --> DSDPlus? Or are you running SDR Software --> VB Cable --> DSDPlus?

 

[wgbecks]

Any chance you can be more specific, by providing an RRDB database link to the exact system you are monitoring, along with a mention of the particular site?

Are you running FMP24/FMPA/FMPP --> Direct Link --> DSDPlus? Or are you running SDR Software --> VB Cable --> DSDPlus?

All good questions that may provide answers!!!!