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Uniden Owner Tech Support For current owners to get support with their scanners from existing or past owners. If you do not own or have model experience please restrict yourself to the other sub-forums.

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Old 05-27-2014, 7:27 PM
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Default USB cord reduces reception

I just noticed that when I have the usb cord plugged into the computer or wall charger, my reception is cut down to nothing. I found this out by using WX channel. It would be loud and clear without the cable plugged in but dropped to nothing when usb is plugged in. Any ideas.
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Old 05-27-2014, 7:32 PM
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Quote:
Originally Posted by a23051coug View Post
I just noticed that when I have the usb cord plugged into the computer or wall charger, my reception is cut down to nothing. I found this out by using WX channel. It would be loud and clear without the cable plugged in but dropped to nothing when usb is plugged in. Any ideas.
I have a 436 plugged in to vehicle power and see no issue like that on 700/800 Mhz but I did previously detect poor UHF performance... With your report, I may try the same reception test on battery only power.

Have you tried 700/800 Mhz reception with and without the power supply?
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Old 05-27-2014, 9:15 PM
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Yes I have tried 700/800mhz with same results. Could it be a scanner issue that needs to be sent in.
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Old 05-27-2014, 10:56 PM
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Originally Posted by a23051coug View Post
Yes I have tried 700/800mhz with same results. Could it be a scanner issue that needs to be sent in.
You may be correct that it needs to be sent in to be fixed but it might help if you could try a different USB cable to try out and use a different USB port on your computer just in case it is not the radio.

Although I sure do not see how this would affect reception unless something is wrong with the radio. My 436HP works just fine with the USB plugged into an AC adapter, computer, or car DC adapter.
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Old 05-28-2014, 7:11 AM
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Default BCD436HP USB cord reduces reception

I have noticed when I use my older Dell laptop to program the BCD396XT, 436HP and even my GRE PSR-800 I get noise on some analog freq's after I am done programming and the scanner starts to scan and I still have the scanner plugged into the laptop. I have had to lock out a few of them to be able to keep scanning. When using a wall wart to power the scanners I have no issue with noise on any of them and no change in reception with or without the wall wart powering the scanners.

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Old 05-28-2014, 8:55 AM
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Quote:
Originally Posted by a23051coug View Post
I just noticed that when I have the usb cord plugged into the computer or wall charger, my reception is cut down to nothing. I found this out by using WX channel. It would be loud and clear without the cable plugged in but dropped to nothing when usb is plugged in. Any ideas.

Using an attached antenna? If so anything metallic in the vicinity will attenuate the signal. Depending on the signalstrength , type of item,size,etc., etc.. Just basic radio theory.
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Old 05-28-2014, 9:01 AM
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PC's are very RF noisy. Likely a lot of RF getting directly into the scanner conducted by the USB cable, which will result in RF AGC kicking in and reducing apparent sensitivity in multiple largely unpredictable places across the spectrum.
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Old 05-28-2014, 10:55 AM
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I use a right angle USB that seems to help. An external antenna does help significantly reduce local (PC) interference.

Last edited by Russell; 05-28-2014 at 11:19 AM..
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Old 05-28-2014, 11:21 AM
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Default Try a ferrite bead

Find a clamp on ferrite bead large enough to wrap the USB cable around a couple of times. I wanted to use the USB cable on my BCD396XT for remote control and it wiped out stuff too. Placed a clamp on ferrite bead on it ,and it got rid of all the RFI coming thru the cable from the computer.

Measure the thickness of the cable. Double it and see if the inner diameter will fit inside one like this. Pack of 5 Steward 28A0640 0A2 Ferrite Cylinder Clamp on Black 100 MHz | eBay
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