Question about back round noise

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chazcarly

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Question
Freq. 453.5625 my local PD here in NJ...There is like a static noise in the back round??? Also the NFM signal strength has no bars???? I dont under stand how that could be. I am less than 5 miles away from the tower. Other freqs miles away are stronger?? Do I have somthing set wrong??
Thanks

BC785D
 

jim202

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Have you thought that they may have a problem with their radio transmitter or antenna system. Maybe your not listening to the station you think your listening to. The PD may have changed frequencies.




Question
Freq. 453.5625 my local PD here in NJ...There is like a static noise in the back round??? Also the NFM signal strength has no bars???? I dont under stand how that could be. I am less than 5 miles away from the tower. Other freqs miles away are stronger?? Do I have somthing set wrong??
Thanks

BC785D
 

chazcarly

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Ringwood NJ
Have you thought that they may have a problem with their radio transmitter or antenna system. Maybe your not listening to the station you think your listening to. The PD may have changed frequencies.
Well I have a scanner at work and they come in clear......???? BC8T. I think it started when I set the tone to the freq, because I was getting a overpowering PD on the same freq from far away....
Anyone???
 

ilgrant

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I wonder if the receiver is being overloaded if you are less than 5 miles away. If your radio has an attenuator feature you might want to turn it on and see if it solves the issue.
 

davedaver1

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Auburn, CA
If there's interference from either a transmitter on the same frequency or Intermod, that will definitely leave noise on a signal being received. Once the proper tone is detected, you essentially have two signals in the receiver. It sounds like that's what the issue is.

One possibility is setting attenuation on that channel (I think the BCT8 and BC785 support that). Attenuating that frequency may reduce the distant transmitter's effect.

One thing you can try is to reposition the antenna - sometimes that will improve the balance of things. I use an Antenna Craft ST2, and I had one somewhat distant transmitter that was always really noisy. Rotating the antenna on the pole 90 degrees completely resolved the issue. Even with omnidirectional antennas, you can try to "null" out the offending signal.

If the distant transmitter is in a different direction from the transmitter you want to listen to, a directional antenna might help, point towards the transmitter you want to hear.

Good luck!
 

chazcarly

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Location
Ringwood NJ
If there's interference from either a transmitter on the same frequency or Intermod, that will definitely leave noise on a signal being received. Once the proper tone is detected, you essentially have two signals in the receiver. It sounds like that's what the issue is.

One possibility is setting attenuation on that channel (I think the BCT8 and BC785 support that). Attenuating that frequency may reduce the distant transmitter's effect.

One thing you can try is to reposition the antenna - sometimes that will improve the balance of things. I use an Antenna Craft ST2, and I had one somewhat distant transmitter that was always really noisy. Rotating the antenna on the pole 90 degrees completely resolved the issue. Even with omnidirectional antennas, you can try to "null" out the offending signal.

If the distant transmitter is in a different direction from the transmitter you want to listen to, a directional antenna might help, point towards the transmitter you want to hear.

Good luck!

Ok ....This is what I found........I had the Attenuating turned on already.....I turned it off and now I get signal bars...Full Strength !!!!!!!! and the back round noise went away!!!!!!!!!
Thanks A lot BUT Any Ideas Why???
Matt
 

kruser

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Ok ....This is what I found........I had the Attenuating turned on already.....I turned it off and now I get signal bars...Full Strength !!!!!!!! and the back round noise went away!!!!!!!!!
Thanks A lot BUT Any Ideas Why???
Matt
Any idea why you were getting background noise? Is that your question?

If so, the attenuator reduces the signal level by up to -20dB. Even though your signal without the attenuator on shows FULL bars, that does not really mean the signal is a full strength signal. The digital (bar type) meters used in many modern day devices are not true S-Meters.
They only give a visual indication of a signal but do not really tell you the signals true strength. When you had the attenuator on, that lowered the signal by 20dB which was enough too weaken the signal enough to make it sound noisy. That is normal behavior for an attenuator and does not mean anything is wrong.

The main use for the attenuator on scanners is to reduce strong nearby signals so the scanners can continue to recieve other signals such as the ones you want too hear. Too much of a strong nearby signal will cause overload or desense which can kill other signals and you would hear nothing or you may hear signals with other signals mixed in with each other.
If you have no problems on the frequencies you monitor, then by all means, leave the attenuator off. On the other hand, if you hear odd sounds or what sounds like other transmissions coming in on the channels you normally monitor, then try and turn the attenuator on for those channels. Having it on can eliminate intermod, overload or desense but not always depending on how strong the interfereing signal is at your antenna.
Sometimes more drastic measures need to be taken but I'd not worry yourself with anything else at this point.
Be warned that turning the attenuator on when trying to monitor a distant station will or may reduce the signal so much that you can no longer hear the intended signal. This sounds like what was going on with your signal and why you had noise. The attenuator was reducing the signal level so much that there was hardly any signal left for the scanner to capture. This in itself will introduce background (white noise or hiss) noise into what you hear. There is a point where a signal is considered "full quieting". This is the point where there is no perceptible noise in the received signal. As the signal strength decrease, more noise is added into the signal and a point is finally reached where the human ear can detect the noise. As the signal gets even weaker, the noise grows stronger. By turning the attenuator on, you are weakening the signal by about 6 times its original strength hence the added noise.

Hope this helps!
 
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chazcarly

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Joined
Nov 24, 2006
Messages
143
Location
Ringwood NJ
Any idea why you were getting background noise? Is that your question?

If so, the attenuator reduces the signal level by up to -20dB. Even though your signal without the attenuator on shows FULL bars, that does not really mean the signal is a full strength signal. The digital (bar type) meters used in many modern day devices are not true S-Meters.
They only give a visual indication of a signal but do not really tell you the signals true strength. When you had the attenuator on, that lowered the signal by 20dB which was enough too weaken the signal enough to make it sound noisy. That is normal behavior for an attenuator and does not mean anything is wrong.

The main use for the attenuator on scanners is to reduce strong nearby signals so the scanners can continue to recieve other signals such as the ones you want too hear. Too much of a strong nearby signal will cause overload or desense which can kill other signals and you would hear nothing or you may hear signals with other signals mixed in with each other.
If you have no problems on the frequencies you monitor, then by all means, leave the attenuator off. On the other hand, if you hear odd sounds or what sounds like other transmissions coming in on the channels you normally monitor, then try and turn the attenuator on for those channels. Having it on can eliminate intermod, overload or desense but not always depending on how strong the interfereing signal is at your antenna.
Sometimes more drastic measures need to be taken but I'd not worry yourself with anything else at this point.
Be warned that turning the attenuator on when trying to monitor a distant station will or may reduce the signal so much that you can no longer hear the intended signal. This sounds like what was going on with your signal and why you had noise. The attenuator was reducing the signal level so much that there was hardly any signal left for the scanner to capture. This in itself will introduce background (white noise or hiss) noise into what you hear. There is a point where a signal is considered "full quieting". This is the point where there is no perceptible noise in the received signal. As the signal strength decrease, more noise is added into the signal and a point is finally reached where the human ear can detect the noise. As the signal gets even weaker, the noise grows stronger. By turning the attenuator on, you are weakening the signal by about 6 times its original strength hence the added noise.

Hope this helps!
THANKS for taken the time to explane this to me..... I fully understand it now. That is what was happening..
Matt
 
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