RFI-Proof WiFi Router?

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  • Problem
  • Updated 2 years ago
After tracking down the source of recurring spikes of interference all across the spectrum, I have determined that I need to replace my RF-noisy Linksys WRT-110 WiFi Router. I have tested its power supply without hooking it up to the router, and it seems to be clean, until I hook it back up to the router. My assumption is that the router itself is the source of the interference. Does anyone else have this problem?

Does anyone have a recommendation for a proven RFI free WiFi router?
I don't want to spend an arm and a leg, but I must solve this interference problem.

Thanks
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Ken - NM9P, Elmer

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Posted 5 years ago

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Photo of George Molnar, KF2T

George Molnar, KF2T, Elmer

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Apple AirPort works well - fine for PCs, too.
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Ed, K0KC

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Ken,

I have had not problems with my very inexpensive Cisco/Linksys WRT 120N router.

I do have a bit of a problem with my Motorola SBV5121 cable modem on 160m however. I just swapped this modem for my old Arris (part number unknown) that was giving me a lot of trouble (spikes) on 160m and 80m. The Arris modem had an internal switching power supply that was causing the problem. I could eliminate the problem by unplugging the modem, but that was not a good solution since I normally need access to the Internet during amateur radio operations. I did buy a backup battery for the Arris which cured the problem, but the modem is programmed to operate only about 20 minutes on Internet, but it does run the modem about 24 hours for the telephone.

The problem with the Motorola cable modem is a signal about 10 dB above the noise floor that floats across the 160m JT65/JT9 spectrum which is where I primarily "hang out" on that band. This is a bigger problem on my 6700 than on my 5000, probably since the 6700 is right on the network.

Ed, K0KC
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W5XZ - dan

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Ken, i find some SMPS's make more rfi when loaded ( with a current demand ), than when just floating; others, vice versa; if it's easy, can you try to power your
existing router with a linear p/s, or even temporarily with a battery?

73. Merry Christmas, W5XZ, dan
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Ken - NM9P, Elmer

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That was my plan for this even when I get home.
First I have to locate some additional power supplies among my many "junque box" (High class junk box) items.
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George Molnar, KF2T, Elmer

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Welcome to the Society for the Advancement of Linear Supplies. For a while, I think I got a reputation as the "choke guy" at my local Radio Shack, as I was buying them out of all their snap-on toroids. Junque Box transformer supplies are great around the house, too. Switch-modes are banned in this casa.

Still pick up the neighbors (and don't get me started on Christmas decorations), but it's better, now. Lots better.
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Rob Fissel

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2 years later, and this made me laugh. Where can I send my dues to join the SALS?
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Ken - NM9P, Elmer

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Update:
I hooked up the router with a radio shack linear 12 supply and the interference pattern is the same, so my thought is that it is the router, not the supply that is to blame.

I had an older WRT54G that I had in storage for several years and tried to hook it up, but apparently it has fallen to static discharge and is now "bricked" until I can "un-brick"it. SO it looks as if I will be in the market for a new router...

Any suggestions, in addition to the Apple Air that are RF-clean?

Thanks
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Bruce

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Ken
I'm using a R6300 from Netgear with gigabit output to a Netgear gigabit switch to Cat 5E cables. The router also has "AC" wireless rates that are very fast but I am all cabled and don't think there many client devices available now. Takes two routers to get near gigabit speeds. My antenna (8.0 Dbd gain)
175 feet away from my three computers with no RFI at 1KW.
Works for me but I don't know how typical my experience is.
Good Luck,

Robert Cline N5FD
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WA6FXT Mike

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Ken,

  I run two Air Port Extremes in my house, with one of them less than 2 feet away from my F6700 and never see *THEM*; now if I could get my solar array to quite down, during the day... But, 6KW is a lot of solar, for an urban home. :^)


73's de Mike


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Tim - W4TME, Customer Experience Manager

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These issue are usually power supply noise being radiated over the connected Ethernet cables and/or the power cable.
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Ken - NM9P, Elmer

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In this case, I tested it with a 3.5 amp linear power supply, not a wall-wart, and the interference is still the same.
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Stan - VA7NF

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I had interference problems to an extreme with gigabit cisco/Linksys brand switches. Returned them all to Cisco (I'm a reseller) and replaced the network with NetGear ProSafe series (GS510TP as backbone with POE and multiple remote GS108T boxes. The backbone supplies power to the remotes thereby eliminating wall-warts.
Also starting to look at testing POE to DC (6/12/18V) to use the network as low power (35W) distribution system.
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K1UO - Larry

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Im using the ASUS System with the RT-N66U dual band gigabit router as close to where the underground phone line enters the building as possible and then use the ASUS USB-N66 USB Wireless Network Adapter to connect the Shack PC to the INET and then use the ASUS EA-N66 Wireless Ethernet Network Adapter directly into the Flex6700 to access the LAN. Works flawless with no downtime due to RFI. I am running K3 and an Alpha 9500 just a couple feet away from the ASUS wireless units with no loss of connectivity at 1500 watts. YMMV
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Tim - W4TME, Customer Experience Manager

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I'll add one vote for Netgear.
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Bob G W1GLV

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I'll add another. no problems with Netgear.
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W4YXU

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My shack is in the basement on an isolated (by a VERY good xfmr designed for isolation), separately grounded (4 ground rods kept moist by condensate from the basement de-humidifier!) and therefore my computer to LAN connection must be wireless.  So I use an Edimax CV-7428NS switch/wireless bridge.  The Flex and PC are direct connected to the Edimax and the Router (DlinkDIR655) are upstairs be hind the TV in the living room.

The noise now seems limited to power line stuff when the outdoors dries out but it isn't very bad most of the time.

Jim
W4YXU
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Ken W9IE

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Ken,

Make sure you do not have a Cat5 cable connected to the router and the other end
open, "not connected to a piece of equipment"....   It can cause hash....

Ken  W9IE
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Stan - VA7NF

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Two notes:  Since you are using a condensate from a dehumidifier, I assume the ground rods are through the floor.  I did that but made sure the holes were sealed to prevent Radon coming into the basement.  The condensate needs a trap as well.

Also if that transformer is using an isolated NEC safety ground, check your local codes.  It probably requires special colour outlet boxes (orange) that identify isolated ground.  I did the same but used MFJ isolation power bars.

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Mike, W8BE

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I Just bought a Netgear G3505 switch and it is noisy to the extreme.  It's not the power supply.  It's the switch itself.  Pretty much wipes out the upper bands.
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Mal G3PDH

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On a related topic I tracked down some spikes down to my Dell monitor with HDMI video. Another Dell monitor without HDMI, only SVGA and DVI is clean so I have switched them around. The spikes were a few khz apart and started on 20m upwards. Interestingly they seemed to be received via the antenna despite being part of the station hardware.
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Tim - W4TME, Customer Experience Manager

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Since RFI is actual radiated RF, so I would expect it to be received by the antenna and show lower (possibly much lower) signal strength with the antenna disconnected.
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Walt - KZ1F

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Ken, I have a Netgear 1750AC router and it is fine plus plus way better than a mere type N router.