Noise on the LAN Cat5e Cable leaving the Router

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  • Updated 3 years ago
  • (Edited)

My setup is Linksys EA6500 wireless/wired router then cable on to Linksys switch.When unplugging switch noise goes a way.So I tried another switch I had and the same issues.
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For Detection I am using a 6 meter RX and I gain 2 S-units of noise using the router switch combo and ((also direct to the router)) it is the same with noise levels.

I tried some beads at both ends at the router and at the switch  and wrapping various combinations and no improvement.

My question could this be fixed by EMI LAN filter or maybe Fiber in between the router and switch? Better Cabling?

Is there hope as this is straight out of the router noise via cat cabling?

73 Jeff

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AA0KM

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Posted 3 years ago

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SteveM

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Are you sure it's from the cables? It could be the wall wart.
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AA0KM

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I put beads on both wall warts switch and router. Just wondering maybe better cable out there?

Just strange right out of the router to the rig I get this. My cable is 50 feet up thru the house and

down the walls to the radio room. But just the radio to the router beads on both ends and still the

noise. I have heard video guys run into this issue and tough to crack. Hope it Is not EMI from in the

attic of the house. Anyway will see what comes up.

Doesn`t effect the other bands to much just 6 meters. 'So trying to clean up the RFI/EMI a little. :)

73 Jeff


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Doug Hall

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This should help:

http://www.w5zn.org/files/Slaying%20the%20Grim%20Reaper%20of%20Internet%20Router%20Noise%20on%206%20...

Sounds like exactly the issue you are facing.
73,
Doug
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AA0KM

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I have been around the house plugging and unplugging stuff and the above picture band noise must be out of my control..73 Jeff

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AA0KM

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One more comment as I forgot to add. I used a 13.8 volt Linear Power supply on the router check this out. It made it worse even with with the added toroid's.
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Al K0VM, Elmer

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Depending on the type of linear PS, it may have gotten worse because the negative terminal of the DC has an internal connection the the AC safety ground..  A linear wall wart would not have that  problem.  Just a thought.  have you tried cores on the DC line to the router ??

AL, K0VM
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AA0KM

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Yes I did very much so.

73 Jeff

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Winston VK7WH

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Jeff, have you tried connecting the flex directly to a laptop and powering the Flex from a 12 Volt battery, with the power to your entire house turned off ?

This will do two things.

1) It will enable you to establish what noise IS coming from within your house and what is Not.

2) It will enable you to isolate the individual things within your house that are causing noise when you turn them back on.. Make sure you turn each circuit on one by one, with your shack power on last again, plugging in individual items one at a time..

In your case, perhaps you have already pinned the source down to the router, but I know in my case it was the only way I was able to pinpoint the real source of my noise, and it was not coming from where I had originally thought it was.

It is an interesting excise to do, and may turn up some surprises, as it did for me

Good luck

Winston VK7WH
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Stan - VA7NF

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I replaced my entire Cisco/Linksys system with NetGear because of uncontrollable noise.
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George Molnar, KF2T, Elmer

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Is there a way to try a metal enclosure? That has helped me with several devices.
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AA0KM

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Plastic router case as most are but my switch is a metal shelf mount Linksys  8 port commercial type. I will keep your enclosure idea just encase Pun intended..lol


(Edited)
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Stan - VA7NF

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My worst noise creator was a Cisco/Linksys SRW2008P backbone (8 ports with POE driving downstream switches.  Metal case, grounded.  It put the noise as common mode on all connected cables.
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Charles - K5UA

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Spent an entire morning trying to eliminate noise and birdies on 17 through 10 meters. Tried multi passes through round torroids on all cat5 cables going into and coming out of the Linksys router" as well as coming out of the computer and the Flex. Nothing helped. Birdies as well and slowly drifting S9 noise humps.

By accident my fellow contester, who was installing N1MM for me, turned off the SteppIR controller to the 4 element SteppIR and the birdies and driftingnoise hump was cut in half. Removing the 33 volt DC SteppIR supply from the controller virtually eliminated the birdies and the drifting noise hump. Since I have two SteppIR antennas, I switched the power supplies and the birdies and drifting noise humps were still gone. Putting the power supplies back on the controllers in the original configuration brought the birdies back and the drifting noise humps back. I can't blame the power supply because it did not cause the birdies and noise on the other SteppIR controller. All I know is the problem goes away when the power supplies are switched between the two controllers. I bring this up because others may have noise that is coming from a SteppIR power supply and may need to check this out.

Another wierd problem showed up just after this one. With both the DB-18 SteppIR and the 4 element SteppIR pointed at Europe, the noise floor on the 4 element SteppIR was nearly 20 db higher than the DB-18 SteppIR. Stations that were easily copy on the DB-18 were difficult on the 4 element SteppIR. I live in a rural area, so I have a 900mhz Yagi for WiFi internet service from town 3 miles away. Just to see what would happen, I removed power from the CAT5 cable going to the WiFi yagi with the 900 Mhz transceiver built into the yagi. The noise floors on the DB-18 and the 4 element yagi were now identical. The 4 element SteppIR is about 40 feet from the WiFi 900 Mhz yagi and in the beamwidth of the WiFi pattern. The DB-18 is 90 degrees off the axis of the 900 Mhz yagi and about 90 feet away. Apparently the 900 Mhz yagi transmitter was raising the noise floor in the 4 element by 20 dB!!! I bring this up because others may have these WiFi internet services in the near field of their antennas and be experiencing noise sources that they can't identify. The noise floor differential was worse on 10 meters and got better as frequency decreases, eventually not being noticed by the time the frequency was down to 20 meters.

You never know til you know.
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KY6LA - Howard, Elmer

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Noise on SteppIR 33V power supplies, especially the older ones is a well known problem.

Likely one SDA-100 controller is drawing more power than the other and pushing the flaky power supply into oscillation when connected to that controller.
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Charles - K5UA

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Spent an entire morning trying to eliminate noise and birdies on 17 through 10 meters. Tried multi passes through round torroids on all cat5 cables going into and coming out of the Linksys router" as well as coming out of the computer and the Flex. Nothing helped. Birdies as well and slowly drifting S9 noise humps.

By accident my fellow contester, who was installing N1MM for me, turned off the SteppIR controller to the 4 element SteppIR and the birdies and driftingnoise hump was cut in half. Removing the 33 volt DC SteppIR supply from the controller virtually eliminated the birdies and the drifting noise hump. Since I have two SteppIR antennas, I switched the power supplies and the birdies and drifting noise humps were still gone. Putting the power supplies back on the controllers in the original configuration brought the birdies back and the drifting noise humps back. I can't blame the power supply because it did not cause the birdies and noise on the other SteppIR controller. All I know is the problem goes away when the power supplies are switched between the two controllers. I bring this up because others may have noise that is coming from a SteppIR power supply and may need to check this out.

Another wierd problem showed up just after this one. With both the DB-18 SteppIR and the 4 element SteppIR pointed at Europe, the noise floor on the 4 element SteppIR was nearly 20 db higher than the DB-18 SteppIR. Stations that were easily copy on the DB-18 were difficult on the 4 element SteppIR. I live in a rural area, so I have a 900mhz Yagi for WiFi internet service from town 3 miles away. Just to see what would happen, I removed power from the CAT5 cable going to the WiFi yagi with the 900 Mhz transceiver built into the yagi. The noise floors on the DB-18 and the 4 element yagi were now identical. The 4 element SteppIR is about 40 feet from the WiFi 900 Mhz yagi and in the beamwidth of the WiFi pattern. The DB-18 is 90 degrees off the axis of the 900 Mhz yagi and about 90 feet away. Apparently the 900 Mhz yagi transmitter was raising the noise floor in the 4 element by 20 dB!!! I bring this up because others may have these WiFi internet services in the near field of their antennas and be experiencing noise sources that they can't identify. The noise floor differential was worse on 10 meters and got better as frequency decreases, eventually not being noticed by the time the frequency was down to 20 meters.

You never know til you know.
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Luis del MOlino

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Charles:

If you have RF in the shack going to electrical ground through your rig through your power supply, the worst thing you can do is trying to get it off adding a good ground cable from the rig to earth.

What you are getting now is a cable ground with RF radiating inside your shack. You'll agree with me that you  wish all your RF goes to your antenna to be radiated there, but not be radiated in your shack.

Worst of all, this ground cable now is becoming part of your receiving antenna too and you'll agree with me that you do not wish to receive all electrical noises generated in your shack to be received by your ground cable.

The RF in your shack is due to RF circulating OUTSIDE your coaxial cable.
So please, use baluns up in any antena (horizontal or vertical) to avoid RF circulating outside braid of your coaxial cable, and ununs with ferrites inside your shack to avoid the braid of your coaxial cable act as a receiving vertical antenna capturing RF directly from your antenna.

These are the good solutions and not the commong ground cables inside the station. Use this ground cables for electrical security but put on them ferrite chokes to avoid they carry RF in your shack.

73 Luis EA3OG.
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KY6LA - Howard, Elmer

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Likely one SDA-100 controller is drawing more power than the other and pushing the flaky power supply into oscillation when connected to that controller.
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Charles - K5UA

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Probably so, just very happy we inadvertently stumbled upon the source. Always assumed it was coming from the neighbors house. Can't assume anything when it comes to birdies and noise. It's especially important when you can see all this junk on a high resolution panadapter because you just can't ignore what's in your face.

BTW, thanks for your effort on the noise presentation. Since viewing some of the Mike Holt videos on Youtube about some of the myths about grounding, I was wondering if you are aware of any good explanations of the concept of an RF ground. Specifically, one of the quotes from the Mike Holt video is "electrons do not want to go to ground, they want to go back to their source". It got me wondering why RF on a chassis or a feedline would be attracted to and dissapated by a connection to ground. We all have accepted this as a truism over the years, but why, or maybe HOW, does RF picked up by conductions in the near field of an RF radiator get resolved by a connection to ground? I've seen it happen, everyone seems to agree it is a truism, but I it would be nice to know why. I understand what an AC ground does and doesn't do, but I would like to understand the RF side too. Thanks in advance for any light on this subject.
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AA0KM

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Added these close to wall-wart in this fashion and it eliminated somemore birdies.

Not sure why the configuration but it works. These are the small snap-ons .25 inside I believe.

 So yes I have the above mentioned toroid's on the cat5 also. 

This thread can be closed if the power`s that be would like to close it.

I am more than satisfied with all the help here.

My thanks to all. I appreciate it.

73 Jeff 

(Edited)