modem interference

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kc9neq

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i have a rs pro95 with a diamond rh77ca antenna. how do i stop computer modem interference. i am using a telephone dsl external modem. this thing is causing interference on the 154 and 161 mhz range. how do i stop it. whether the scanner is 5 feet or 10 feet across the room i get the interference. its really drivng me crazy. i have coiled the incomming and outgoing lines and i still get it.
any suggestions would be helpful.
 

WP4MZR

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Try moving the modem and (wireless router if you are using one) to a different room. Most of the time the RFI from network devices comes out of the ethernet cables so keep those as far as possible from the radio and change the link speed to 10Mbps on all the ethernet adapters.
 

key2_altfire

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Dude, I feel your pain. I'm having IN-CREDIBLE RFI issues coming from my WiFi router, and believe it or not, it's not the WiFi radio that's the issue, it's the router itself. Part of the problem is the close proximity of the router to my 2M antenna. They're in different rooms, but still not too far apart. I picked up some ferrite toroids that I'm planning on wrapping into all cables attaching to the router to see if RFI is transmitting out of the PS cable, LAN cable, etc. I was able to eliminate RFI coming out of my PC and LCD monitor this way.

Personally I have not had much luck reducing RFI on anything below ~500 MHz by coiling cables... the ferrite seems to be a necessary step to kill off excess noise in the lower frequencies.
 

fuzzymoto

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My DSL modem and wireless router sit on top of my scanners. I have no such interference but I use all external antenna. I did plug in my RH77CA and didn't pick up any noticeable interference. I'd say if you can't identify a bad cable, it may be easier to put an antenna in the attic or outside for yourscanners.
 

Bill_White

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Power Supply?

Are you sure it's the modem??
If I were a bettin man...
I'd bet you have a cheap, unfiltered / bad power supply (wall wart) in the loop.

Check the volts and AMP ratings of the devices.
If they are all 12V they may be connected to a "GOOD" PS which you may already have in your shack.
You may want to invest in a small PS just for these devices:
http://universal-radio.com/catalog/hamps/2184.html
Should be big enough for your cable/DSL box, modem and, router.
Snip the leads off the wall warts and use those.

Add a PWRgate and a battery for an uninterrupted supply..
http://universal-radio.com/catalog/hamps/0965.html
 

kc9neq

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its definately the dsl modem. the model is a speedstream 5100. i coiled the telephone cable and the ethernet cable and it reduced some of the interference, but in i still think the majority is comming out of the modem itself. i get intermittent interferenece when i move the modem back and forth. is there something i can put over or around the modem that will stop the rf leakage?
 

shaft

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If its the modem, then you have a serious defect in it and should be replaced. I doubt its the modem tho, what else is in the room? Computers, flourescent lights, dimmer switch etc...? Is the scanner running on batteries or connected to your residential power when you have the interference?

What happens when you move the scanner further away from what you think the source of the interference is?
 

kc9neq

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i get the interference on both a rs pro95 and a uniden bcd996t. pro95 (battery power) and bcd996t (residental power) when using the stock antennas. i have moved the scanners out of the room and i do not get the interference. when the scanners are connected to an antenna in the attic i do not get the interference. i have eliminated the computer, the computer monitor, the compact fuorescent lightbulb in the room, and the cordless telephone. the interference stops when the modem is turned off.
 

blueangel-eric

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If its the modem, then you have a serious defect in it and should be replaced. I doubt its the modem tho, what else is in the room? Computers, flourescent lights, dimmer switch etc...? Is the scanner running on batteries or connected to your residential power when you have the interference?

What happens when you move the scanner further away from what you think the source of the interference is?
I know this thread is old but i have the same problem only with the Speedstream 4100 modem. i have 2 different size ferrite teroid beads on the ethernet cable but that helps little. I have them stuck through as a pigtail rather then cutting the connector off and sliding them on and putting a new connector on. if i unhook the Ethernet cable or shut off modem and the interference stops.

help?
don't remember the speedstream 5100b being this problematic
 

Diamondmind50

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I know this thread is old but i have the same problem only with the Speedstream 4100 modem. i have 2 different size ferrite teroid beads on the ethernet cable but that helps little. I have them stuck through as a pigtail rather then cutting the connector off and sliding them on and putting a new connector on. if i unhook the Ethernet cable or shut off modem and the interference stops.

help?
don't remember the speedstream 5100b being this problematic

I didnt want to start a new thread being a noob here so I seen this title fit my question so I hope you dont mind me coming in on the tail end of this thread

Military/Air and Satcom/space and NASA seem to be what is most interesting for me to listen to along with what ever carries the most type of various trunked brands so I guess my two choices are the BCD396T or the PRO96 since I have given up on the ICOM IC R20<<< I am going to wait and see if i can grab the IC R20 for 300$ or less in a couple days.

Money I guess isnt the issue vs quality and coverage I am basing that on the 2 comparison charts I printed up and looked over... is there another brand I am missing that carries all that I mentioned and maybe a bag of chips?? ,,

any suggestions from the experts here are greatly appreciated

thanks
 

blueangel-eric

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I didnt want to start a new thread being a noob here so I seen this title fit my question so I hope you dont mind me coming in on the tail end of this thread

Military/Air and Satcom/space and NASA seem to be what is most interesting for me to listen to along with what ever carries the most type of various trunked brands so I guess my two choices are the BCD396T or the PRO96 since I have given up on the ICOM IC R20<<< I am going to wait and see if i can grab the IC R20 for 300$ or less in a couple days.

Money I guess isnt the issue vs quality and coverage I am basing that on the 2 comparison charts I printed up and looked over... is there another brand I am missing that carries all that I mentioned and maybe a bag of chips?? ,,

any suggestions from the experts here are greatly appreciated

thanks

your post has nothing to do with the topic. have you looked at the newbie forum? ;)
 
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