RS PRO-668 Harford County

Hello,
Has anyone had success monitoring Harford Co. with a PRO 668? I have been working with this unit for a few weeks with limited results. Some transmissions are crystal clear, but most are garbled or drop out mid-transmission. Any insight or info would be greatly appreciated.....
Thanks,
Ken

I have a Pro668 also, live just outside of Bel Air and I hate this radio.
I don't think this radio likes Harford county.
It just don't work right.

Please read my post here: Baltimore County P25 CQPSK Explanation.

Sorry for the wordiness, but that explains in laymans terms the issue you're likely experiencing. CMARC uses CQPSK modulation, and it's a real bear for scanners to keep up with when they have competing signals to process.

I have actually had short little hits on the sheriff and MSP down in northern Anne Arundel County in the last couple weeks. Nothing from when they went to CMARC until then, and only on a psr800, the cousin to the 668.

I wonder if they are tweaking their propagation area because they were too tight at the start?

Used to listen to the old Motorola system all the time.

Mark
WS1095/536/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652

Thanks DPCAIN for the explanation on the CQPSK modulation. Seems like the exact problem I am experiencing and I assume Tronman as well. I will have to reread your post to try to grasp more of the concept, as I am new to this. Great big learning curve involved! From what I have read on other threads, the uniden bcd436hp does a much better job decoding on these systems. I would like to find a way to make the pro668 work, but may not be possible. May try a firmware update, once I figure out how to get the software to recognize the scanner. I can update the data base, but not the firmware. I'll keep hacking at it for a little longer until I give up and try a uniden.....

The 436 is not significantly better. No scanner is great.

The keys on any scanner are:

Reduce reception to one tower if you can.

Use of a lousiesr antenna if you have one predominant tower and other weaker ones, or a directional antenna if you are getting hit by many towers. Usually it is the latter but it depends on your situation and location.

Turn on attenuation on the specific system in the scanner. This also reduces incoming signals and can help get it to receiving one tower.

There is a wiki on the Baltimore County system on RR. This system uses the same type modulation. You might find some other things to try.

Mark
WS1095/536/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652

Update: Got the updates on the Pro668 all done and tried a lousier antenna and tweaked a few settings. Not much help. Tried several different locations, including my work location which is inside a big steel building with horrible radio reception. Still most transmissions are garbled. Finally gave up and bought a Uniden 436hp. Night and day difference right out of the box. Haven't really had time to play with it as far as programming and settings go. Can't wait to see how good it can be after some adjusting ect. Very pleased so far. Big learning curve on this radio as well..... Thank you all for your input......