Poor trunking reception

[Anderegg]

Having poor trunking reception on local 700 and 800MHz P25 systems. Signal strength is around -35dBm, extremely strong, but for some reason, we get very broken and choppy reception, with decode error rates sometimes so bad the channels are unloackable. Here is our antenna array on top of our newsroom...hoping someone eagle eyed can help identify what the issue could be. 👀

Paul

 

[sonm10]

Simulcast???

Buy a SDS

-35 Seems really high, too. Try the attenuator

 

[Ubbe]

If all systems you monitor are of that same signal strength, then use a 40dB attenuator to bring down the signal to -80dBm. SDS scanners cannot take levels at -35dBm without having a lot of overload issues. You might still need to find a setting of filter and IFX to clear up some intermod issues.

/Ubbe

 

[Anderegg]

This is with SDS200's, yagi pointed at the transmitting site...just to give a little background.

Paul

 

[sonm10]

Try a less efficient antenna - you need to get the signal strength down

 

[bob550]

Aren't those cellular antennas on your tower? If so, could the carrier have made some recent alterations, such as the addition of 5G capability, that may be causing the problems?

 

[Anderegg]

Aren't those cellular antennas on your tower? If so, could the carrier have made some recent alterations, such as the addition of 5G capability, that may be causing the problems?

That's a Verizon/ATT (700/800 LTE bands) tower 50 feet from our scanner antennas. Do you think that could cause any form of interference?

Paul

 

[blackbelter]

Nearby Cell towers or TT has always caused interference or completely block the receptions .

 

[Mike_G_D]

Personally, I think maaaaybeee...Paul shouldn't attempt facetious dry humor with a touch of ironic jest in the wee hours of the morning after a long frustrating day of struggling with his long ongoing and reasonably well outlined in the past saga of the battle of the neighboring cell towers emissions vs. the Anderegg listening post headquarters...

...but, maybe that's just me...

 

[TailGator911]

Your antennas are very close to those cell towers. That has to be causing some interference. I don't think I've ever seen vhf/uhf antennas that close to a cell tower. I know someone 1/2 mile from a cell tower and it wreaked havoc on his reception. He also has an SDS200 and he finally rectified the problem with filter settiings, global attenuation, and IFX adjustment. Luckily the SDS200s filter/IFX can be tweaked up to a certain point.

 

[kruser]

That's a Verizon/ATT (700/800 LTE bands) tower 50 feet from our scanner antennas. Do you think that could cause any form of interference?

Paul

Pretty much guaranteed to cause issues with widebanded front ends like scanners use.
Commercial radios will have issues as well with the cell antennas that close.

 

[blackbelter]

I have had no reception issues driving/ Parking by a Verizon 700/800 LTE cell tower using my Unication G5 and its blue band stubby antenna. The monitored Trunking /Simulcast TT was about 20 miles away.

 

[kruser]

I have no reception issues driving/ Parking by a Verizon cell tower using my Unication G5.

The Unications have a MUCH better front end with proper filtering compared to a scanner. The Uniden SDS series are the worst for strong signal overload with their wide 8 MHz or so TV Tuner front end chip.

 

[bob550]

That's a Verizon/ATT (700/800 LTE bands) tower 50 feet from our scanner antennas. Do you think that could cause any form of interference?

How long have the cell antennas been installed on your tower; and have you had trouble for the entire time they've been there?

 

[Anderegg]

Personally, I think maaaaybeee...Paul shouldn't attempt facetious dry humor with a touch of ironic jest in the wee hours of the morning after a long frustrating day of struggling with his long ongoing and reasonably well outlined in the past saga of the battle of the neighboring cell towers emissions vs. the Anderegg listening post headquarters...

...but, maybe that's just me...