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LinkSys Routers and other brands known to
cause (We are also
working on a list of computer related equipment See bottom of
article for details we need. Information And A Cure for RFI/EMI from LinkSys Routers and Their Products to Ham Radio? MAYBE! Multitudes of
Ham Radio operators are reporting in various forums, interference in
varying degrees from none, or minor, to MAJOR disruption to Ham Radio
Bands from LinkSys products of all types! The purpose of this page is NOT to downgrade or bash any manufacturer or product line....only to report what others have said and done about the known interference problems specific to the Ham Radio bands and the LinkSys products. There may be other brands causing interference also. Just a little FYI on the noisy wireless router problems causing interference to Ham Bands. Apparently this is a known issue with many Linksys routers and other products from LinkSys whether they are wireless or not and has been ongoing for a long time. We will attempt to give you information, some known models causing trouble, links, sources of discussion, tips, and hopefully at least one cure for Linksys product interference to the Ham Bands. There are other sources on the internet concerning these problems but we will give you some of the more popular ones. You can do a search and find lots more. More about the problem..... Some Hams are of the opinion that the whole bag of Linksys models is involved to one degree or another and that LinkSys knows about the problem but are not very helpful most of the time except in rare instances. Usually the support people just state that they are compliant with the FCC rules and regs and drop the subject! One
interesting question is how did they ever get type approval if they are so
compliant in causing interference to a Licensed Service? Maybe LinkSys has the correct answer! Here are some statements taken from various sources from Ham radio operators concerning LinkSys products: "It seems that all LinkSys products have been produced with absolutely no shielding or RF bypassing of any kind and with total disregard to interference, RFI/EMI, caused to any other device." "Linksys
products have got to be the worst on the
market." "SOME MODELS CAN BE HACKED FOR INCREASED POWER" "My 2 meter rig is now happy that LinkSys junk is gone." "Frankly, I think these things are messier than a spark gap transmitter!" "These routers have also been known to shut down adjacent networks, cordless phones, hf rigs, pagers, baby monitors... you name it." "There's a ton
of pages online about how it creates havoc on Amateur
Frequencies." "Pure hash
caused by trash" "Disconnect it from power......problems are gone!" Editors note...this one says it all! "Try shielding the cables...may help some." "I will
never by another LinkSys product
again." "I have a LinkSys model
DI-524 router. And on and on. What models are involved? According to our research on the web using various forums, input from emails, bulletin boards, etc, as sources, the LinkSys models mentioned below are the worst offenders that create RFI/EMI to Amateur Radio Bands or other frequencies. If you see a model listed below, your results may be different. Please report any rfi issues you may or may not have if you use one of the listed models below......
Linksys
E1200 (Cisco) Router. Since installation I have
had signals, approx. 30 KHz apart from 40 meter thru 2 meters. Power supply is
fine but unplug supply from the router and emission disappears.
Roger Horton K8CIX Silver Springs, NV
89429 Linksys Model EZHUB04 - Doug, G0LQC "I particularly like to use 40M but the Linksys EZHUB04 causes so much interference -- S meter fsd on some frequencies on this band." Linksys Model WRT54G
- John, K8YC...."I had noise spurs about every 30 khz on the 6m band
on my radio. I've owned the same Linksys WRT54G Router/Access Point for at
least 5 years and never dreamed it could be the source of such problems. I
always thought my problem was a local noise source outside the house until
I moved in March 2013 and the noise followed me to the new
house!" Linksys Model WRT110
(info by Larry Mann KD0BLL)----Mine has made 147.585Mhz unusable on 2
meters. BEFSR41 wireless-g router "G" router + WAP BEFSR11 WRT54G
Update....Models in Europe may not be problems ( "CE" marked according to
Roger MW0IDX K3IDX)...thanks to
Roger! BEFSR1 Other Brands Reported To
Cause RFI to the ham bands: Comtrend CT-5374 updated 03-2014 DSL MODEM--- BEWARE! Once the modem is "trained", a wide plateau of white noise takes over 3.795 to 5.15 MHz. No mere annoyance; signal levels to my magnet loop forty feet away, were over S9. With the dipole in the attic, the signal ranged from 10 to 25 over S9. An interesting feature of this noise, is the very sharp walls of the plateau. For instance, there was no signal at 3.79 MHz, but a 10 over signal at 3.8 MHz. On the other end, a 10 over signal at 5.145, and nothing at 5.155 MHz. Already being sufficiently disgusted and disappointed, I did not feel it necessary to check VHF or UHF. The technician has never experienced this kind of radio hobbyist problem before, and had no solutions. We probably should have tried another unit, but being weary of my present noise level, I had no interest in welcoming the Comtrend into my home. The upgrade was cancelled, the technician took it away, and my previous modem was back in place. Until the FCC begins to enforce the Part 15 rules and
regulations again, I strongly suggest that you test any digital devices
that come along. You may be preventing a lot of frustration down the road.
Rick Baumgart KE0NC NetGear WRN3500 03-20-2014 update Actiontec model MI424-WR Rev
D....... generates spurious signals from 2 MHz through 2 meters. NetGear Model FS524S 24 Port Router (N0YFE) D-524 Router (Note, this is not a LinkSys product
but was reported as a noise producer) D-link DIR-601 - Puts out RFI on the 2 meter band. 146.910 is unusable for some reason. Unpluging the router kills the rfi. The RFI covers about 1500 sq. feet due to living in a Faraday cage IE mobile home. I have also found that this router causes problems with cell phones within 1 foot of the device. 73, Benjamin A. Straw - KC9UNS Update added by Keith Thomas 09-11-2012
WB6ANP Brands and model
numbers of routers, switches, DSL modems, etc Linksys SD2005 5 Port Switch
(submitted by Dan, 2e0dpk)
Netgear WNR3500L (reported to work fine on transmit and receive) WNDR3400 Cradelpoint MBR900 Linksys
WRT300N - No problems with rfi on radios or radios causing problems
with it.
Taken from one of the forums and referring to a wireless LinkSys router courtesy of VE3VDC: "When I called their support line they not only knew all about it, they knew exactly who to put me on with for advice. Their support line is at 1-800-326-7114. The problem is
that the cat5 cables radiate the ethernet switching hash from inside the
router." The third harmonics land on mid-VHF frequencies. Basically they suggested: 1) Set all NIC cards to 10 mbps. 2) Coil up extra cable length on a "three finger" form and tape. 3) Disable unused ports. 4) Make certain all connectors are clean and in good condition. 5) Keep the router at least 6 inches from metal objects. 6) Disconnect unused cables. This seems to have worked. No more
washing machine sound every few Khz all across 2 meters... at least for
now. Time will tell if this is a permanent solution. (fingers crossed)
Source of these tips...VE3VDC Another helpful hint....replace
the wall wart power supply with another brand with the same voltage and
current specs...many switching type power supplies are the source of rfi!
Watch that polarity! Some other
good sources, forums, comments, etc concerning the problem with LinkSys
products and Ham Radio: http://www.eham.net/articles/8302 http://www.eham.net/forums/RFI/361 But it doesn't end there... There's lots more on the internet! SOME TIPS IN TRACKING DOWN SOURCES OF RFI IN THE SHACK. These tips may help in locating severe noise sources to 2 meters and bands above that are suspected of coming from your radio or computer equipment. If the source strength is intense and fundamental frequency is low enough, this could be the source of all your ham band problems. Also see tips for HF below. Tips for HF/VHF and above: Stand back several feet from the suspected device or if needed in another room or location if the white noise "floor" is too strong. Adjust the squelch (on vhf transceivers) just to the point that the white noise stops if possible. If it does not, then you will have to remove the antenna and get much closer to the suspect device. On portable shortwave receivers without squelch, tune as needed for a "quiet" hf frequency in the band you have rfi on. Now move the handheld or portable receiver around or near each and every piece of equipment in your station that is near your router or associated cables. This includes it's power supply, wall wart, interconnecting cables, etc. If the squelch breaks and or noise poors from the receiver when you are very close, then you have pin pointed the suspect device! Now remove the antenna from the handheld remembering the device, cable, etc, that caused the squelch to break! After you have removed the antenna, move the antenna connector end of the handheld toward the device.......the noise should increase and break the squelch even higher as you get closer with the handheld if this is the source of the noise to 2 meters. (When you removed the antenna, you greatly decrease the "sensitivity" of the handheld. This helps in pinpointing the exact source.) If your handheld or portable radio has a signal level meter, (S Meter), this will aid in tracking down the source with more accuracy than listening to the noise coming from the speaker. The stronger the reading, the closer you are. With the antenna disconnected, you will have to be very close to the suspected device to detect any rfi coming from it. Now leaving the handheld or receiver probe in the same position (don't move it), remove all cables from the suspect device except the power to the unit. If the noise stops or
gets much weaker and you hear no rfi at or near the power supply (the wall
wart)...one of more cables are most likely radiating trash rf from INSIDE
THE DEVICE! Don't forget the cables going to the computer. Check them too.
Your computer, computer
monitor and associated devices, cables, etc may also be adding to your
problem or could be the culprit! If you remove the power to the device and all noise stops.....you have found your source! BEST Solution.....If it is a LinkSys device.......remove it from service and get another well known brand in a metal case with shielded cables if possible with known good shielding all around! Simple as that. Don't spend good money on extra shielded cables, ferrites, etc and just wasting your time....of course this is up to you. Troubleshooting and locating RFI on the HF Bands. Use a short length of coax connected to the antenna input of your HF rig, portable receiver or handleld HT, with a very small "Sniffer or Probe" loop attached to the other end. In other words, build yourself a very small loop, about 1 or 2 inches in diameter, fed with 50 ohm coax leading to your receiver's antenna input......Don't key your transmitter while the loop is used for obvious reasons!!!!!! You will use the Hf receiver or portable radio to help locate the suspected noisy device just like in the 2 meter procedure above using the "Sniffer" loop on the end of the coax. Make it long enough to reach all devices in your station while listening to your receiver's audio. You may also want to use someone to watch the S meter also for maximum deflection or bars. You may need to use attenuation and or RF gain to reduce your receiver sensitivity during this procedure. You want to have the least sensitivity the closer you get to the source of the noise to aid in pin pointing it. Check all bands and frequencies or the band that you are having the noise on by watching the S meter and listening to the audio from the receiver. Hopefully you will find the culprit. Remember...the most simple thing to do in finding the
culprit is to disconnect the power from each suspected device and if
the noise stops.....you have located the source! Then troubleshoot
further. Don't just turn it off....disconnect the AC power at the
wall outlet! Some devices are still 'on' when turned
"off"! Update by
WB3EME 09-2014 Netgear DG834 rfi noise and a
fix! ______________________________________________ Some comments from the UK! 11-05-2011 Extract from article
above:
"Usually the support people
just state that they are compliant with the FCC rules and regs and drop
the subject!
One interesting question is
how did they ever get type approval if they are so compliant in causing
interference to a Licensed Service?
Question unanswered as of this writing!" "In the UK, it is
generally thought that certification of compliance with EEC
regulations, concerning electronic devices and RFI issues
is, generally worthless.
A manufacturer
supplies test models and is given a certificate of compliance. This
however only means that the supplied model and design are compliant at the
test. If then the manufacturer changes the construction, componets or
worse, a third party is contracted to make the units, then that third
party decides it can save money by ommiting components like filter
capacitors and these units are 'imported' from shady origins lets
say..then the games is, as they say, well and trully
over!
In the UK there are
literally thousands upon thousands of dark imports coming on to the market
because of purchases through online Retailers and Auction sellers. This is
a major source of RFI problems.
Policing of these devices
and so called officially certified units is non
existant."
Regards
John
Edwards
GM7NVA
More RFI Tips and Tricks....click here!. Notes from the Editor: You will notice in the response from LinkSys tech support to VE3VDC above, that they AKNOWLEDGED THAT THEY HAVE THE PROBLEM with the particular model listed! We would
like to thank L D Blake, VE3VDC for informing us of this problem
concerning LinkSys products and the Amateur Bands and inspiring us to
produce this article. To file
a complaint for a Part 15 device with the FCC. Thoroughly document
the situation, equipment types, brand and model number including
frequencies involved
Also on this
page we are attempting to compile a list of brands and model numbers of
your COMPUTER equipment that DOES NOT INTERFERE with ham radio
equipment! 73 N4UJW Hamuniverse.com {n4ujw at hamuniverse.com}
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