odd interferance

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andy1974

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hello all....i am getting a odd signal interferance when i am trying to monitor my countys trunk system. It sounds electrical.....i have tried a few diffrent thing even s outdoor antenna with the same interferance. i have posted a link from a vid on youtube so you can hear the problem ...as i walk aroung the house it gets better then worse. of course my fav easy chair that i like to sit and listen i get the worst. if someone can help me identify the interferance and how to fix it i would be greatfull.

interferance.3gp - YouTube
 

ipfd320

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do you have a cable modem?? take the radio by it ---also take the radio close to any cable lines in the house see if it gets worse-----i had the same problem and it turned out to be a faulty cablevision modem----i found this out doing what i posted and unplugged the power to the modem and the interference stopped----good luck
 

andy1974

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thanks for the responce...howvever its outside the house also .....even like a block away...
 

zz0468

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A ten second snippet isn't going to be sufficient for anyone to diagnose what the problem is. Have you ever gotten good reception there? Is it something that's just started?
 

andy1974

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I can record more of the transmition if you need me too .i just started back into monitoring, the interferance is very wide spread like the whole street.....litterly....it sound like electrical wave sound also here what sounds like a IDEN pulse. if i move around the house / and outside and the neighbourhood the worse spots comes and go. it almost is like its jamming the signal. we have issues with our wifi , cordless phones cell phones and now scanners. I got a outdoor discone antenna and raised it on a 20 mast with rg-11 and rg-6 cable at 30 ft. and it litterly amplified the interferanece. I have place a formale complaint with the fcc and they called me and sugested i call the cable and power company. however of course they say " there is no problem " i am getting so aggravated with this issue it is ruining my enjoyment of monitoring. also i think i should mention that once i leave my street and head in town the signal improves almost insantly. Another thing i have noticed....when i have the rubber duck ant on my base scanner and i wrap my hand around the middle of the antenna and down toward the bnc connector i notice the interferance goes away . the min i remove my have it returns...am i doomed or do i just have to settle for listening to my scanner at work where reception is perfect. FYI moving is not an option at this time.
 
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andy1974

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is a trunking system hard to receive? i mean i am on a very high elevation also. almost los of the trasmitters.
 

scannerboy01

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When did you notice your interference? I noticed that your post was made on October 25, 2011. On that date, the aurora borealis were out and I noticed that my scanner had reception issues throughout the evening. I have heard that the aurora borealis can cause interference issues with communications devices.
 
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Do some research and contact a local Ham Radio club, they may be able to put you in contact with someone that has experience in tracking down RFI and possibly have the necessary equipment to track it down. A good resource would be American Radio Relay League | ARRL - The national association for AMATEUR RADIO that is the national association for Amateur Radio and they have a technical dept. with information on interference issues.
 

andy1974

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i will try and make contact with a group. i am getting the interferance on the 800 trunking band.
 

zz0468

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See if you can record a couple of minutes of the noise and post it. It would also be helpful if people know what system you're trying to listen to. Who knows... It may not even be "interference" in the normal sense of the word. Some systems are simulcast, and if you try to listen outside the designed coverage area, it can sound pretty cruddy.

If you're trying to listen to just one system, an easy and effective fix can be to install a yagi antenna. The yagi then gets pointed to whatever direction gives you the best signal to noise ratio - and that might not be at the transmitter site.
 

ridgescan

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Does it only happen in the 800 band? How are the vhf lo/hi bands there? If it's only the 800 band you need to put the band in search and see if you can locate a horrendously strong pager or other microwave type transmission. If you do locate one that seems to cause the interference put it in a video here-maybe we can ID it
 

andy1974

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well glad you asked that , and just to give more info. yes it seems to be just the 800 mhz band. i think your prolly right .....i need a antenna directed to a transmitter. however i am using a triple trunking scanner. i love the yagi idea and what to just on that with both feet. however i am listening to other bands on the same scanner. i truely dont want to have to buy another scanner for just my trunk system i listen to .and use the other for my conventinaol listening. it kinda defeats the design of the scanner :( ....however i found a post about using 2 diffrent band antennas with one scanner. and i truely dont understand how that would work . any thoughts?
 

ridgescan

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I use two 2-way coax switches by AlphDelta-one for two scanners to one antenna, and one for two HF rigs to one antenna. You could use these switches the opposite way, one scanner to two antennas, and you can switch between antennas. This will allow you to get your yagi:) hey if you can blow a little coin on this great hobby and you can get away with a second antenna up there I say go for it!
This link is for illustrative purpose-shop around there are cheaper prices
http://www.durhamradio.com/alphadelta-delta2-2position-antenna-switch-ontario-canada.html

as you can see, good old HRO is $20 cheaper
http://www.hamradio.com/detail.cfm?pid=H0-008459

They say these switches are only good to 500 megs but I get perfect 800 reception off this switch-no noticable loss of signal between it and direct fed-keep in mind though my feedline is LMR240 and 20'.
 
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andy1974

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yea , thats a manual switch, not that i am lazy , but.....that would be kinda off a pain to have to switch all the time
 

ridgescan

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yea , thats a manual switch, not that i am lazy , but.....that would be kinda off a pain to have to switch all the time
Im not too well-informed on this but I believe they have what is called a "diplexer" that hams hook to the back of their rigs but I think the diplexer is activated with the transmitter so I don't think you can use it on a scanner. Someone please educate further.
Far as switching goes it's not a huge effort-the only drawback is you could only scan one band with one antenna then throw the switch for the others. If you mount the switch close to your scanner like I did it's so easy.
 

zz0468

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Im not too well-informed on this but I believe they have what is called a "diplexer" that hams hook to the back of their rigs but I think the diplexer is activated with the transmitter so I don't think you can use it on a scanner. Someone please educate further.

A diplexer is a passive device that consists of several filters. The filters separate the signals by frequency. One filter is a high pass filter, the other is a low pass filter. They work as well on a receiver as they do on a transmitter.

To the OP: Using two antennas to solve the problem can work, but read the sticky thread. It can open up a big can of worms if you don't do it right.
 

Nap

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"we have issues with our wifi , cordless phones cell phones and now scanners"

BTW I have a floor lamp with 3x20W 12V bulbs and a voltage converter in the pedestal. I didn't open it up to see what kind of converter is inside but that POS produces a strong RFI interference to the point of shutting down my wifi and making a strong racket on all frequencies of any radio receiver I have. I figured it out by walking around the house with a radio in my hand.

As a desperate measure you can turn off the power in your house from the general circuit breaker and remove batteries from all (cellular) phones or other devices. If the noise goes away, it's something inside your house. You can then turn power on selectively and note which circuit brings the noise back again.
 
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Nap

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I've listened to your recording again. It's too short and there are some other noises over it. But. Can you go to this site:

Digital Modes Samples

and listen to the "BPL" sound to see if it matches yours.

If yes that's bad news.
 
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