Trunk interference

[securitydan]

Monitoring local PD with my Pro 164, am getting their transmissions but they are boken up. When they send or recieve its like the scanning of the trunk freq or something is interfering. There is a quick interupt about every 5 sec. I am scanning Puyallup PD in Pierce Co. WA. I have the control numbers talk group id's etc all programed in. (p.s. there has been a new control freq added recently due to upgrade I will report to RR).

 

[ka3jjz]

There's precious little details here to even begin to suggest a solution. Are you using the scanner in a home or in a car? What antenna are you using? You mentioned an 'upgrade' - did this system reduce their transmit power (ask in the Washington forum...)? Are there a number of NexHell or pager towers nearby, which could be causing an overload condition known as desensing? And what is this 'quick interrupt' (which might be a pager, since it seems to happen every 5 seconds or so)? The database shows that there are 2 alternate sites for the Tacoma/Pullyalup trunk - did you try using these?

The antenna on that scanner is, at best, a compromise on most bands - did you try a different antenna? It's also possible you are running into a simulcast distortion issue - most scanners have problems with systems like these. This phenomenon is described in detail here...

Simulcast digital distortion - The RadioReference Wiki

More details needed...best regards...Mike

 

[W2PMX]

Do you have a priority channel or weather priority enabled? That sounds like the scanner interrupting itself every 5 seconds to check the priority channel.

 

[gmclam]

MOT 800 Control Channel reception

Monitoring local PD with my PRO-164, am getting their transmissions but they are boken up. When they send or recieve its like the scanning of the trunk freq or something is interfering. There is a quick interupt about every 5 sec. I am scanning Puyallup PD in Pierce Co. WA.

What I would do is program ONE frequency and SCAN it. You can accomplish this by locking out all other frequencies in the same bank and turning off all banks except the one with this one frequency. The frequency to scan is the active control channel of the Tacoma system. It's one of the 4 in the DB, just listen to hear which one it is at the moment.

Put your scanner in MAN mode on that frequency, with the frequency set to MO mode. You can turn down the volume if the noise bothers you. What kind of decode percentage do you see on the display? I like to see a % above 75%, above 50% should give you good results, but a percentage below 25% is really NOT acceptable.

The scanner MUST receive this signal WELL in order to trunk track (monitor) the system. If you are not receiving the signal you could try a different site (which means a different frequency), or try a different antenna. I use the RS800 rubber antenna to monitor such a system and avoid monitoring other bands on the same scanner at the same time. If you're using an outdoor antenna I hope you have great quality coax connecting it to your radio. Long coax runs and/or low quality coax will often present a lower signal level at the scanner than just using a rubber antenna on the scanner.

If you are receiving this signal above 50% SOLID... and with NO other channels on including PRIority, do you still have the problem?

 

[Shutterbug2]

Hey Security Dan in Edgewood ... Shutterbug2 (on-line name) here also in Edgewood. Recently acquired BC346t scanner ... the 'new' generation of computer programed radio. I'm looking for local person to help teach me how to program and use this new technology.