996 xt no consistancy in reciving

[swstow]

i have programmed several 996 xt for a local fire deptment in butler county ohio, i got a call from the fire cheif today asking about a problem he is having on a few of the radios i programmed, the problem he stated to me is that the reception is not consistant ( like fire dispatch is clear and clean on one transmitton but not on the next ) the radios are in the admin offices and fire houses so they are stationary all have had the factory antenna replaced with 800 antennas, what should i be looking for as a possible prolbem

thanks jim

 

[arvellabill]

I have found that all ditigal transmissions are like that, They go "digital" I think motoral and the rest of the industry have been trying to fix this for years.

 

[ka3jjz]

You have to keep in mind that signal levels are going to change moving from location to location. What sounds perfect at one firehouse may need some tweaking at the next. You can't expect the level of the signal to be the same everywhere you go.

The other possibility - and if the system you are listening to is multi-site, this is a strong possibility - is a multipath distortion issue. This effect is discussed in our wiki at the article below;

Simulcast digital distortion - The RadioReference Wiki

I suspect this would even be an issue if you were trunking a single site, but in an urban area with lots of buildings and such that could block or bounce the signal around.

73 Mike

 

[JStemann]

You may have to go to the actual location where the radios are located just to see what kind of signal levels they are getting. They may have to go to external antennas or, on the flip-side, they could be too close to the site or a cell site, overloading the front end. In that case you could see what happens with/without the antenna. You can also set all of the audio types for the TRS to "digital" if this is the Butler County P25 System.

Also, I'm guessing you're talking about the Butler County TRS. Are they just listening to the fire or are they also listening to the PD comms? I see a lot of encryption used on that system for PD, just wondering if some of the encrypted t/g's are starting to get thru before the 996 catches them.

jeff.

 

[derevs]

Also bear in mind that you are using a back of set antenna and that while distance is a consideration you also have interference from people moving about the rooms that could also effect the reception.
What to do? Place the scanners near a window or install outdoor antennas.

 

[Skypilot007]

I would go with a good quality external antenna for starters. What you decribe is to often the case with indoor antennae. Performance will be intermittent at best when indoors unless your within a mile or so of the repeater site.

 

[swstow]

thanks for all the input guys / to answer some of the comments / yes its the butler P25 system and they are scanner all fire and fire grounds and only their police dispatch / we had talked about out side antennas ( we are using RS 800 rubber ducks now ) i was in the cheif's office today his was next to the window.

thanks again, time to read up and spend some time monday at his office and watch and listen

jim