LinkSys Routers and other brands known to cause  Interference to Ham Radio Equipment Another plague for the Ham Bands? Updates added 09-11-2012  This page contains brands and model numbers of routers and other associated computer equipment  known to cause interference (RFI) to ham radio equipment and possible cures for the problem. (We are also working on a list of computer related equipment including routers that  DO NOT CAUSE INTERFERENCE (RFI) to Amateur "ham radio".) Your help is needed in sending us the brands and model numbers of your computer equipment that DOES or DOES NOT INTERFERE with your ham radio equipment.   See bottom of article for details we need. Please share your experience with other hams worldwide.) 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! Hams worldwide are having problems associated with LinkSys products. 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? Question unanswered as of this writing! 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" "Absolute Junk.....put it where it belongs....in the 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. With power on,  the router is breaking squelch on my 2m receiver over 30 feet away.  This is with the squelch full clockwise and scanning is out of the question.  With the router off, the Yaesu 7800 is performing as advertised." "The 624 is history as soon as I can get a replacement." 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 frequencies. If you have 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 Models Reported To Be RFI Producers....(including other LinkSys products)..... this list is not all inclusive..there may be others: (send use the brands and model numbers) Linksys Model WRT110 (info by Larry Mann KD0BLL)----Mine has made 147.585Mhz unusable on 2 meters. LINKSYS SRW208P PoE Switch - Submitted by Dan, 2e0dpk (whooshing noise hf thru 6 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! WRTS54GS "I have a linksys router WRTS54GS. It is "CE" marked and should meet a minimum requirement when it comes to RFI. It does not. It is impossible to use the 6 meter band when this router is on. And i have measured that it radiates form around 21 mhz and up to around 300 mhz. Some of the noise is even in the spectrum used my emergency services. This router is going in the garbage!" LB5KE Norway 10/100 hub from Linksys (Model EFAH05W) BEFSR1 BEFW11S4 Other Brands Reported To Cause RFI to the ham bands: Netgear DG834 (See update and fix below by Bob, G4CPV)   Netgear WNR2000 N300 series.  6 meters is trashed at my station. unbelievable bad noise at regular intervals. Netgear WNR 2000 UPDATE 02-19-2012 Netgear WNR 2000 (From KF5OBM)---- I was getting interference on 147.160 MHz from my Netgear WNR 2000. The tip from VE3VDC was helpfull.  I took the cat 5 cable from the router to the dsl modem and coiled it around a form 2 5/8" diameter (first thing I could find to wrap around).  That fixed the symptoms. It did not seem to be radiating from anywhere else. Dan KF5OBM 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, Model DI-624 ver.  E1. 4 ports & 108 G wireless..... (Also not a LinkSys product but was reported as a noise producer) Hash on 2 meters for 3 to 4 hundred feet away!   D-Link 4300 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 Netgear fs-108 8 port switch produces s9 noise on 14.270 area as well as others. Net gear ndr-3400 v2 produces s5 noise on the same band. Send us your brands and model numbers that cause RFI to your ham equipment n4ujw AT hamuniverse.com Brands and model numbers of routers, switches, etc reported to be OK, FINE or NO interference noted to ham radio equipment 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.   I use a Yaesu ft-8800 and Yaesu FT-450AT Henry D. Akin    AJ4PM Send us your brand and model number that DOES NOT cause rfi to your ham equipment. n4ujw AT hamuniverse.com     NOW ONE (CURE)......HOPEFULLY from VE3VDC! 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." (Editors Note...the keywords here are {INSIDE THE ROUTER}....THE SOURCE!) 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 See his excellent article "RFI From Computer Networks" here. 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: Note, The eham.net links below may require some rather long drawn out reading and sorting time to wade thru all the QRM in the articles. 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: Here is a handy method of locating many noise sources on the HF/vhf ham bands. Using a 2 meter handheld, adjust it to an unused frequency. Leave the "Rubber Duckie" antenna attached. (Note that you may also use a portable shortwave receiver tuned to the respective hf band with an external "loop" probe setup as described below.) 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 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 07-25-2011 from Bob, G4CPV Netgear DG834 rfi noise and a fix! At the shack here I have a Netgear DG834 which is a 4 port ADSL router. This was emitting some hash around 3.68MHz at 20dB over 9 and also at some other frequencies around 4MHz and above. Using your suggested technique of a small loop on the aerial lead I wound about 5 turns around a pen and used it to sniff the source. The router is fed from a 15v AC wall wart and is rectified in the router. The noise was very strong around the transformer and also from the back of the router where the power feed was. Opening the case, the PSU  was standard ie bridge rectifier with a 2200uF smoothing cap. Unfortunately this cap was manufactured by Teapo and from previous experience of computers, monitors and PSU's these caps are useless. The cap was changed and also a 0.2uF cap placed in parallel with it. Once done the noise completely disappeared! The odd thing is the Teapo cap was measured and appeared absolutely fine both in value and ESR but on changing the scope showed a vast reduction in hash and even more so when the 0.2uF was added. I did previously try a few turns on a toroid which reduced the hash somewhat but didn't need it at all afterwards. Flushed with success I am now investigating a lower strength noise which is across all the low frequency bands and it's looking like it might be a Netgear switch. 73's Bob G4CPV -- Bob Fisk Good luck ______________________________________________ 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. We usually do not report on concerns such as this but due to the severe nature of the problems with LinkSys and other brands and RFI on the Amateur Radio Bands, we hopefully can inform more people about what they may be getting into if they use LinkSys products or other brands in or near Amateur Radio Stations...... Use these listings with caution. They are reported here in good faith but your experience may be different depending on your operating conditions and radio equipment setup. SEND US YOUR INPUT! DETAILS NEEDED. If YOU have any valuable input to this article pertaining to other models of LinkSys products or other brands and models interfering with Ham bands and/or known cures, please email us with the exact models and description if possible of the interference and cure if known. Please do not duplicate models and brands already listed. On this page we are attempting to compile a list of brands and model numbers of your COMPUTER equipment that DOES OR DOES NOT INTERFERE with ham radio equipment! Email your info to n4ujw at hamuniverse.com. Please include any or all details that may help others. The best will be edited for posting here. You may notice the Google ads on the left side of the page with LinkSys advertising.....we are not responsible for the Google ad content. They are sorted by Google as related to the content on this page. I doubt that any of you would be interested anyway in buying LinkSys products if you read this complete article and do your research unless you know for sure it does not interfere with you! If you are still interested in LinkSys...then the choice is yours. 73 N4UJW Hamuniverse.com     {n4ujw at hamuniverse.com}