436 receiving what 536 is not same sentinnel loads

[dfw1193]

My 436 with pro voice upgrade receives johnson county sheriff dispatch tg 5769 but my 536 right beside it with the same profile load as the 436 from sentinnel does not receive it at all the 436 is on the original antenna and the 536 is on the outside discone otherwise both have the latest firmware and the same load config, this is crazy but its happened all night long so far without fail the 536 never receives while the 436 does everytime all other systems loaded are received on both units.

Cant figure out whats going on.

 

[dave3825]

You only mention that your 436 has the pro voice upgrade . Does the 536 have the provoice upgrade?

 

[dfw1193]

No the 536 does not however the rr database shows its on the fort worth regional system p25. I dont know how to see if its a pro voice system for them but thats the only explanation that would explain it.

 

[GTR8000]

ProVoice has absolutely nothing to do with P25, so that part is irrelevant.

Try taking the 536 off of the outdoor antenna, and put the little telescoping antenna on the back of the scanner. See if that makes any difference in receiving the Johnson County Simulcast site.

What is likely happening is that with the outdoor antenna, you're receiving too much signal (multipath distortion) from multiple subsites* of the Johnson County simulcast cell, whereas the 436 with the rubber ducky antenna is only receiving the nearest subsite. Sometimes less is more, especially when dealing with simulcast cells.

* A subsite is an individual physical site that is part of a simulcast cell. Simulcast cells are comprised of two or more subsites, all transmitting the same signals on the same frequencies at the same time.

 

[ofd8001]

A while back the cable for the antenna cable for my vehicle's 536 broke. I received my local simulcast system better than I ever did. So as noted about, better antennas are worse for simulcast.

I would not have fixed it, but there are other things I want to receive.

 

[Ubbe]

So as noted about, better antennas are worse for simulcast.

What is important are that you try to receive one tower much better than the others. Reducing the signal level from the antenna until you only receive one tower also works but as you noticed all reception then goes bad. Can you set the 20dB attenuator in the scanner only to the frequencies of that particular system then it might work better without making the rest of systems perform worse.

/Ubbe

 

[dfw1193]

Discovered the opposite issue I swapped the sd card from the 436 to the 536 after the 436 just received a transmission. Then I noticed when the 536 brought up the johnson county simulcast site there were no reception signal bars while the 436 has 3 or 4 signal bars. Tried 5 different antennas on the 536 with the same result, all the other sites I have work fine, so all I can figure is when the 536 went through the power brownouts and losses about 6 months ago something besides the sd also took a hit causing slight desensitizing on the signal path so it needs a stronger signal now. Dont know for sure since that site was not setup on the 536 prior to the power issues, but it works on everything else so its good i have an sds200 coming soon.