Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 Next   Go Down
  Print  
Author Topic: RFI from router cables  (Read 6339 times)
VE3TMT
Member

Posts: 400




Ignore
« on: May 28, 2008, 05:00:42 PM »

I am using a Netgear wireless router for the laptop upstairs and my shack computer is hardwired to the router which is connected to the cable modem. I am getting RF from the system every 50 khz or so from 160-20m. I have tried powering the router by a battery and the noise is still there. If I shut the router off it goes away. If I unplug the ethernet cable between the router and modem it goes away. So is the noise coming from the router or the modem. If I bypass the router altogether and plug my computers ethernet cable directly into the cable modem everything is quiet.

So it appears to the the cable between the router and modem. If I unplug the same cable at the modem end the noise is still there, it only disappears when I unplug it from the router end. All the antenna cables are closer to the modem than the router.

Any ideas?

Max
VE3TMT
Logged
WA7NCL
Member

Posts: 625




Ignore
« Reply #1 on: May 29, 2008, 08:06:09 AM »

Try clamp on ferrites on the modem / router cable.

I would consider buying another brand or model of router.  They are not expensive and you could spend a lot of time on fixing the one you have.

The repeating frequency of the RFI seems strange for an ethernet signal.  I would have guessed that you had RFI from the wall wart or other switching power supply or RFI from some CRT display (horizontal sweep frequency)

I have an older non-wireless netgear router. It is quiet.  The older netgear stuff is built in metal boxes.  Maybe you can find a router geared more to commercial service that has a metal enclosure with better RFI that the one you have?

Sometimes this RFI stuff is like the lotto!
Logged
KI4CRA
Member

Posts: 62




Ignore
« Reply #2 on: May 29, 2008, 08:46:30 AM »

Max,

   I'm using a Buffalo Tech. wireless broadband router, of course I am totally wireless, at least my laptop is.  The router is hard wired to my desktop and the modem.  I've ha no issues with this one.  I did have an older Linksys wireless broadband router, had some issues with the router itself, but no noise.  I too think, try the ferrite chokes, if that doesn't take care of your problems I think it would be time to replace not only the router, but all the cables you are using.  Hope this helps.


73 de Mark
AI4HO
AEC Indian River Co. Fl.
Tech Specialist
Indian River Co. Fl.
Logged
VE3TMT
Member

Posts: 400




Ignore
« Reply #3 on: May 29, 2008, 07:05:17 PM »

I may end up looking for some higher end ethernet cables. The old router was a Trendnet and it gave off the same noise. I would have thought the Netgear would be quieter. I did try something else but couldn't get the laptop to find the wireless router.

I plugged the cable modem into a 4-port hub. The two basement computers were plugged into ports 1 and 2. I ran a cable from port 3 on the hub to the Netgear router. The lights came on to show connection and the laptops wireless receiver will find the router, but I can't seem to connect to the internet from the laptop. If I could get this to work, I can just unplug the wireless router when the laptop isn't being used, which isn't that often. But for some strange reason, it won't access the internet.

Max
Logged
WA3SKN
Member

Posts: 5484




Ignore
« Reply #4 on: May 30, 2008, 09:11:26 AM »

Max, you are working with square waves here... lots of harmonics!
The short answer is shielding, shielding, shielding.
Make a Faraday shield around the router and any switches out of some aluminum foil and ground it.  Try shielding the CAT 5 cables and grounding at one end, this is better than ferrites.
Those plastic cases and un-shielded cables do not block RF very well!
Oh, and do plan for some ventilation.  Don't block the air holes!
Good Luck!
73s.

-Mike.
Logged
WM2P
Member

Posts: 26




Ignore
« Reply #5 on: June 01, 2008, 07:52:04 PM »

I had all sorts of RFI with Linksys and if you do a Google you will find others with the same problem. I bought a Belkin wireless and my problems went away. Same cables, different brand.
Logged
N0MUD
Member

Posts: 85


WWW

Ignore
« Reply #6 on: June 18, 2008, 10:11:41 PM »

Max, I am also using the Net Gear and I have the main net gear boxes in the radio shack.  I have one desk top in the shack, one desk top in the living room and I also use an HP laptop with the Net Gear disk that slides into the side of the laptop and I have NO interferance from any of them.  I'm using the wires that came with system and the system I am using is totally wireless for all three computers.  I guess maybe I am lucky.  Only thing I could think of is maybe upgrade your Net Gear unless yours is the upgrade model and/or read all the blogs and see what everyone has to say.  Pick and choose as you see fit and good luck.

73s, Mike N0mud
Logged
KI6FOM
Member

Posts: 9




Ignore
« Reply #7 on: January 30, 2009, 07:09:05 PM »

I know this thread is a little old so you may have solved your problem already, but this may help others. I too had this awful noise from the twisted pair cables in my installation. I tried all kinds of stuff including ferrites, rerouting cables, and swearing a lot. It turned out the solution was simple. I just bought a cheap wireless card for my shack computer and switched over to strictly wireless. The only cable in my installation is from the modem to the router and I kept it very short (and left the ferrites on it, though I don't think they are needed).

This totally solved the problem and the wireless card was less than $20.

Hope this helps.
Don - ki6fom
Logged
WB4BYQ
Member

Posts: 179




Ignore
« Reply #8 on: March 29, 2009, 07:41:31 PM »

I solved the RFI Birdes from my neighbors LinkSys wireless router and PC with shielded cat5 cables. One
shielded cat 5 from the cable modem, and the other from
the PC, both to the LinkSys device.  I did not use any
type 31, or 43 snap on ferrite cores.
Logged
N7ZM
Member

Posts: 131




Ignore
« Reply #9 on: April 11, 2009, 06:36:04 PM »

I am completely wireless except for Gateway into phone DSL line. Absolutely no RFI. Change out your equipment for wireless equipment that talk together up in the GHZ.
73 Ron N7ZM
Logged
KB7QND
Member

Posts: 43




Ignore
« Reply #10 on: January 29, 2011, 08:43:13 AM »

I was wondering if the poster solved the issue.

My wireless modem which is over 100 feet from my shack (through the length of my house) is also giving me random interference on HF frequencies at spacings from 10Khz to 60Khz apart.

I've tracked mine down to the wireless router.  Disconnected all cables from the router and unplugged the modem, noise still there.  Then unplugged the wireless router, noise goes away.  Plug back in, noise comes back.

So the wireless router is generating noise from inside its plastic case or along the power cable/wall wart.

Completely wrapped the wall wart power cord around a ferrite core ring, no change.
« Last Edit: January 29, 2011, 08:54:20 AM by KB7QND » Logged
K1CJS
Member

Posts: 6034




Ignore
« Reply #11 on: January 29, 2011, 06:47:44 PM »

Even though this thread is old and the originator probably already solved his problem, quite a lot of these problems are traceable back to the wall wart that runs the router, a separate switch (if used) or the modem itself.  Other problems can be found in the cabling--sometimes cheaper cat cables used are more prone to interference production.

The routers being manufactures these days are also being made cheaper, and sometimes the only answer is to replace it with a better quality router.
Logged
NA4M
Member

Posts: 61




Ignore
« Reply #12 on: February 04, 2011, 06:46:50 AM »


The routers being manufactures these days are also being made cheaper, and sometimes the only answer is to replace it with a better quality router.

What is considered a better quality wireless router these days?  I have an old Linksys WRT54G fed from an Arris cable modem.  Someone earlier mentioned a Belkin.
« Last Edit: February 04, 2011, 06:48:52 AM by NA4M » Logged
DAVER
Member

Posts: 63




Ignore
« Reply #13 on: March 08, 2011, 11:52:19 AM »

I too have had a lynksis router cause problems. It only would happen when plugged into the comp and theconp on(when talking with each other). Assumed it was just the cheap cable...but was the least of problems. I live in a city (20-40 wifi nets in range at all times). With that type of density It all depends on whos got what on at what time...tvs...etc. That mixed with a 50kw clear channel right up the st and about 10 other semi high power stations close by I spend a lot of effort in filtering the front end!
Logged
WB4BYQ
Member

Posts: 179




Ignore
« Reply #14 on: March 08, 2011, 12:24:56 PM »

switch the network to 10 mb and the birdies will go away.  100 mb ethernet will radiate carrier noise on 20 meters at 14.021  14.098  14.151  14.211  14.274  14.332 MHz  these freq all near these areas.  when which to 10 mb the carriers fall away.  i found that 10 mb half duplex works very well for me, running timing test.  i have heard these same carriers on 15 and 10 meters.  running the cat 5 cable thru a 1/2 snap on  type 31 or 43 about 3 turns spaced apart on the outside of the core will reduce or allmost cancle the common mode rfi.

richard
Logged
Pages: [1] 2 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!