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Author Topic: odd sounds, Data sounds over voice audio  (Read 1667 times)
MDNITERDER
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Posts: 146




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« on: September 06, 2012, 12:40:19 AM »

 I listen to my police scanner now and then and lately i hear what sounds like pager data or square wave sounds over the people talking, you can make it out as if its mixed in, what could this possibly be?
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K1CJS
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« Reply #1 on: September 06, 2012, 04:53:26 AM »

How old is the scanner?  After the recent changes to allowed bandwidth, (narrowbanding) there can easily be what you think is interference when using older scanners.  What's happening is that the older scanners are picking up adjacent frequencies in use, and some of the frequency users are going digital--which can sometimes could like data packets being received.

If the scanner is adjustable as to the width of the received frequency, you can eliminate the 'interference' by selecting a narrower bandwidth.  If it's an older scanner that doesn't have that adjustment, you'll just have to live with the interference--or get a new scanner.
« Last Edit: September 06, 2012, 05:10:01 AM by K1CJS » Logged
W4OP
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« Reply #2 on: September 06, 2012, 06:53:36 AM »

It sounds like you may be getting pager intermod- a pretty common problem.
See:
http://www.parelectronics.com/scanner.php

Dale W4OP
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MDNITERDER
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« Reply #3 on: September 06, 2012, 12:47:17 PM »

It is fairly new, its a Bearcat BCD996T not the newest XT version but it has the digital,

 It almost sounds like pager data but just flat square wave sound, and goes away when they un-key, I can turn off the squelch and when the person un-keys its normal static, so Whatever it is, i wonder if its some way form of encryption or they are carrying someone else's signal further. I will see if I can get a short clip of it
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MDNITERDER
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« Reply #4 on: September 06, 2012, 12:55:01 PM »

Also I forgot to mention this is just the Local Sheriff that that this is happening on.
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KD0REQ
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« Reply #5 on: September 06, 2012, 01:02:53 PM »

"what's the frequency, Kenneth?"

side-splatter is quite likely.  have you ruled out any baby monitors, wi-fi, DSL, service-over-powerline, and other stuff?  a bunch of us have grown up using AM signal generators to tune FM radios.

could also be they have newer class multifunction radios, and are not running F1, but maybe F9 with their laptops in part of the sideband.  http://www.acma.gov.au/webwr/_assets/main/lib100342/emission(rib8).pdf
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MDNITERDER
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« Reply #6 on: September 06, 2012, 01:30:29 PM »

 I will post the exact frequency in a little while when I get in my truck, its int he 460mhz range so I know its not wifi or baby moniters. this happens over long distances of 30+ miles. You do present something that i am trying to figure out, maybe something that's a multifunction radio and the proper receiver may break the two signals into there respective uses, One being analog audio and one being maybe a laptop with GPS data
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KE3WD
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« Reply #7 on: September 06, 2012, 02:13:47 PM »

Certain public service systems do exist that also handle short burst of digital data in order to keep track of mobile units, it may be something like that as well.  The purpose-designed transceivers may be able to filter that out, but your scanner likely wouldn't have that capability.


73
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MDNITERDER
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« Reply #8 on: September 06, 2012, 02:18:38 PM »

 I wish it was a short burst, but its not, its the whole time they are keyed down. I will attempt to get a recording of it. if not I can simulate it with adobe audition, its like a rolling square wave constantly over the single,
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