PSR-800: Scanner desensitized! Fix?

Status
Not open for further replies.

policefreak

Member
Premium Subscriber
Joined
Jan 5, 2007
Messages
2,087
Location
Berlin, NJ
So at one time I used to have 2 PSR 800s. They both received exactly the same. I sold it recently then was asked to program it. Again, with exception of it being just awful on p25 phase 2 it received fine. I then get a call a few weeks later that it was really acting up. So I look at it. Lo and behold it is only getting 3-4 bars on the same system in the exact same spot compared to my other PSR 800 which is solid 5 bars and stuttering almost as bad. I confirmed ATT was OFF on the unit in question, the DSP was the same, and same results between 3 different RS 800 antennas including 2 new ones. The metal connector attached to the radio did not appear loose. Am I missing something?
 

gewecke

Completely Banned for the Greater Good
Banned
Joined
Jan 29, 2006
Messages
7,452
Location
Illinois
Check the corners of the case for signs of droppage, if no damage to the Bnc connector? Either that or maybe the P25 system you're listening to made changes? 73, n9zas
 
D

darunimal

Guest
ADC, DAC, AGC, and Decode Threshold, all the reason you probably had decode problem before since they all play an important part in the decoding (some call it receiption, which it's not), but the 5 bars could have been showing you it had, with, to high of gain (antenna) applied; for the System to be decoded properly, in the first place. The first 4 settings, I mentioned, are to work harmoniously with the DSP, if set correct; make 1 setting wrong, throws the rest off. As per what and where the second owner took it and what he did or didn't do only he knows. Or possibly, the System's radio tech changed something!!!

Try a reset and reprogram and go from there, with less gain this time, with altered previously mentioned setting; for better Phase II decode-ability.
 
Last edited:

policefreak

Member
Premium Subscriber
Joined
Jan 5, 2007
Messages
2,087
Location
Berlin, NJ
OK that's good to know! Makes sense. So both ADC and DAC deal with gain. Now can someone tell me the difference between the two? And how does the AGC affect decode?
 
D

darunimal

Guest
ADC Analog to Digital Converter,
DAC Digital to Analog Converter,
set them to-high "create noise on the line" to/from the DSP,
set them to-low a "cause image refreaction" on the line to/from the DSP,
same with AGC Automatic Gain Control
0 to +1 have been observed to offer "best performance" for "most" Phase II systems on all three settings.


Decode Threshold is like a Digital Squelch setting for the scanner, for the scanner to understand what conditions "it should use" to move onto (or look for) the next site (and/or tower).

75-99 is perfect for: perfect none mobile conditions,
15-85 is for more imperfect mobile and extremely windy days,
50-90 is for lightly breezy days and none mobile, roam conditions.

1 barely any signal at all, if any.
99 Perfect


DSP changes how the signal is processed, quicker adjustments higher, slower lower, 72 is "somewhat more ideal" for Phase II

Now several members will constantly say this or that but offer no solution, until we take a survey and find what users use across the country use, we will never know. Hence, why firmwares are adjusted by manufactures and number may change between models but these should be used as "starting points" and "guidelines", not absolutes.

Many members just don't want to give up the valuable info they have learned for whatever reason.... Constantly seeding misinformation and just like they use to, with frequencies

Do let the fools play you about purchasing SDRs and Professional radio BS, none is more affordable or as convenient as a scanner, you need at least 1000 radios and 3000 dongles to compete with a PSR-800 ability to listen to the same amount of SYSTEMS.
 

wa1nic

Member
Premium Subscriber
Joined
May 28, 2012
Messages
263
Location
Westfield, Ma
FWIW, I believe there are a couple of back to back protection diodes right across the antenna input connection.

If someone used it within a few feet of, say a 50 VHF/UHF radio, it is possible that one of the diodes is shorted.

I had it happen on a GRE analog/trucking mobile rig once.
 
Status
Not open for further replies.
Top