BCD996P2 Background Noise

I just purchased my first digital trunking scanner. I have a couple of conventional frequencies that seem to be exaggerating the background noise (static like sound) especially when compared to my BC125AT. The 125 still has its rubber duck antenna while my 996 is connected to a much larger antenna with good coax. I don't see a reason that the 996 is making some of these transmissions completely unreadable when my 125 sitting feet away can receive them perfectly. I expect it from some of the air band stuff but not from these public safety repeaters. I have tried swapping antennas around and moving the scanner away from possible causes of interference. Here is a breakdown of the frequencies for comparison. This is also a replacement...the first one had the same noise issues (also had a non-functional function knob) and the new one hears these the same way. It receives both my local VHF and 800mhz P25 systems perfectly and every other repeater outputs very well. Any thoughts or suggestions?

154.055 - Noisy
154.995 - Noisy
155.430 - Sounds great

My thought is that the rubber duck antenna is attenuating the background noise. I would look at your much larger antenna location as it may be picking up some nearby garbage in the system.

You are listening through the scanner's speaker?

Intermodulation interference? With an antenna that is going to provide more signal than one that is indoor and connected at the radio, there may be strong signals at the antenna input that are mixing in the receiver causing distortion.

Have you tried the attenuator function on those frequencies? If the ridiculously high 20dB attenuator does not kill all the desired signal, is the noise less with the attenuator?

I still cannot figure out why we are still getting scanners with 20dB attenuators. It is useless for reducing signal overload. It usually just kills all the signal you want to receive. 10db would be much more useful and 6dB most useful. 20 dB attenuation passes only 1% of the original signal!

I have tried moving my antenna around a little, however I only have 10 feet of coax so there are not many options.

Yes the sound is present through the built-in speaker. It is also present in my ProScan recordings.

I have not tried the attenuator, I kept reading that in most cases it blocks the whole signal. But I'll give it a shot.

curtisdevault said:

I have tried moving my antenna around a little, however I only have 10 feet of coax so there are not many options.

Yes the sound is present through the built-in speaker. It is also present in my ProScan recordings.

I have not tried the attenuator, I kept reading that in most cases it blocks the whole signal. But I'll give it a shot.

Click to expand...

The attenuator very well could kill the entire signal, but if the desired signal is strong enough it may come through. I would love to know what resistors could be changed out for the BCD436HP to have the built in attenuator be 6dB instead of 20dB. 20db is pretty much a useless value.

Connect the 125 to the same antenna that you have the 996P2 connect to and see what happens.

Is the antenna on the 996P2 located indoors or outdoors? What kind of antenna is it.

Also disconnect any cables that connect to the computer from the 996P2 and see if the problem improves.

I did a little more fiddling this morning (got sidetracked by my Wi-Fi going out) and connected the larger antenna, it is indoors for now to the 125 and it received fine. Switched it back and the signals were so noisy I couldn't copy what was being said. I'll unplug the cables to the computer tonight and see what happens.

So I sat down next to both scanners swapping antennas back and forth. I think the 996 is just making the noise louder since the speaker seems to be to better than the 125. I noticed no difference in swapping antennas around. I think it's just the way it is. But for the heck of it here is a link to the of the recordings. the Law North/West recordings are considerably noisier the MSU ones. The noise seems to come and go...making me think it's environmental. I noticed no difference either when the scanner was completely unplugged from the computer. Just seems weird to me that the noise is really only there on 154mhz channels...

https://1drv.ms/u/s!AglxpY8VKhXIgbAJt4ZfOzbmgjrAGw

Any further thoughts would be greatly appreciated. Should I try requesting a second exchange from Amazon or spend the time on the phone with Uniden? Or is it just the way it is. My commercial radios hear these perfectly...but that makes sense commercial vs consumer.