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K-Y Filter Testimonials
I have been experiencing significant RF interference since I bought my
plasma television. The RFI causes my ADSL modem to lose synch while the
TV is on. I did not see a specific testimonial on your web site about
that specific problem. Have you heard whether your filter will block
the interference I am getting from the TV?
After reading the article about plasma tv generated rfi, at the following url, I think that the RF-1
filter might indeed work well for you. The RF-1 filters out all of the
K-Y Filter Co.
I need the following filter:
Model RF-1 (price=$24.95 US Dollars) eradicates HF (short wave 1 to 30 MHz) interference and it works with DSL modems as well as dial-up modems.
I attempted to order it through your web page but when attempting to write my address in the fields presented, I couldn't because I am from Australia. In the field STATE, I couldn't write NSW as only American states were available.
That commerce site leaves a lot to be desired but I think I found a way to make it work. When you get a list of USA states, to choose from, just scroll to the very top of the list and you will find a blank line. Enter the blank line. And then put NSW in the next line(province line). Don't forget to change the very first line of the order form from USA to Australia before you start.
I hope that this will work for you. Let me know if it doesn't.
We now have a new purchase page at:
K-Y Filter Co.
Subject: It came today and the good news is!
Date: Mon, 09 Jun 2008 13:01:47 +0100
The filter just arrived and I have put in series with the other one, on my DSL modem, the
good news is that on 80 mtrs, which was the worst I can now transmit 200
watts and the link remains stable. I cannot thank you enough.
I did write to the RSGB with your url etc but I will now write again and
tell them of the outcome and hope they publish the information, I am
sure they will.
I haven't been on the air for months and now I can start yakking again.
Thank you so much I am delighted and it's cost me peanuts.
My ADSL filter arrived in Australia after 7 days and frankly it worked superbly, I was having trouble with our legal limit on 80 metres, after fitting the filter the ADSL remains rock solid, it's great to get something that works exactly as described.
I received the filters on Thursday. I've installed them on two of our phones and the results are phenomenal! I have attached pictures and you are quite welcome to put one or
both on your web site, as well as all or part of the following paragraph as a testimonial.
Before putting the Model RF1 filters on my phones, when I transmitted with 500 watts on
either 40 or 30 meters, I took the phones in my house out completely. Both my wife and my mother gave up their conversations and called the person back at a later time.
I installed the filters and the problem went away! It was not reduced by 50%, or 80%, it was gone completely. I went from totally destroying the legibility of their conversations to
not even a whisper of my CW or SSB transmissions. These filters work as advertised . . . in fact they work far beyond my wildest dreams. There was absolutely no negative affect
on my DSL Internet either. These things are the magic bullet when it comes to solving telephone RFI.
Paul VE1DX Nova Scotia
When i transmit on 80m my Noise margin on the router drops from 18db to 00db and then i lose the connection , would your filters help??
Thanks for the inquiry. I am not sure what type of connectors your system uses. Our filters use the middle two pins of an RJ-11 connector.
Our RF-1 filter should take care of your RF problem, if the connectors are compatible.
K-Y Filter Co.
I just wanted to compliment you on your web site. I do a lot of online
shopping and rarely do you see a merchant giving out this much information.
You present a balanced view of a problem that is absolutely driving me crazy
and let me make an informed decision as to what I should do without a
tremendous amount of hype concerning your product. I wish that other online
merchants would adopt the same approach as it seems to come from a man who
has confidence in himself and is genuinely trying to be helpful. So what I
did is I purchased one. I hope it works! Irregardless of the results I
obtain (hope springs eternal), I respect you for your commitment to poor
people like me who are mystified by the disembodied voices they hear when
they pick up that phone...
Have a happy, healthy and prosperous New Millennium!
Thanks for the order and the email with the nice comments. I just
shipped your filter. You should get it Saturday or Monday in the US
Thanks again and best regards.
John K. Browne
Received the ADSL filter today John,
You can put this on your website.
I am an ex R&D tech and I must say this about your service and product.
The service is Great from Ordered on July 4, 2007 over the web in the USA
and arrived in Perth Western Australia in my Mail Box July 12, 2007 - Great
About the Filter I have a 4 element monoband yagi at 10m high 2 meters away
from the house also run a linear so the beam hangs over the roof of the
house this induces considerable RF in the telephone lines in the roof. Each
time I send a SSTV picture the ADSL would drop out due to RF overload the
ADSL modem sits in the shack and telephone cables run 300mm apart from the
RF coax to the roof not an ideal installation but one of mechanical
Installed the RF filter and now ADSL modem runs perfectly I can even plug
the house extension back in which was impossible before, so the ADSL RF
filter does exactly as I was hoping and provides sufficient filtering to
allow me to TX pictures while running my website.
Hope to see you soon from VK - Land 73 + GD DX
AMAZING! Restaurant is batch-processing its backlog of credit card receipts
right now. This is the end of a problem that persisted over eight months. My
client thinks we are geniuses! Spoke with the manager when part arrived by
FedEx this morning. He plugged the filter in himself and was thrilled to
hear no more Talk Radio on his modem. You rule and so does the AM-1 filter!
Just wanted to let you know that the filter works fantastic! I just plugged
it into my Imac and then plugged the phone cable into that and the results
are far better than I could have hoped for. Before, my 56k modem was hooking
up as slow as 2400 baud and no matter what speed it hooked up at the
connection was tenuous. I had to slow down the speed of the driver to get
any sort of reliability in the connection and that made my modem act like a
28k with it's accompanying slower data transfer. Now every time it connects
at full speed which makes the internet almost bearable. Every once in awhile
I get a "spike" of interference that will disconnect me so if it becomes a
problem I believe I will purchase another one for the other end of the phone
cord. We shall see...
Anyway, great doing business with you. Great web site, business attitude and
a product that works!
Thank you for your prompt service. Your filter arrived last night, as did a special "bulletproof,
EMI-hardened" phone approved by the FCC. The phone cost me, with shipping, $87.69, and attenuated
the noise by a significant margin (we live within a couple hundred yards of an AM broadcasting tower).
Your $24.95 filter virtually ELIMINATED the interference, and was the clearcut winner.
I'm sending the phone back and buying 3 more filters. I'd previously tried an $11 filter from Radio Shack,
but it was worthless--made the problem WORSE, so I didn't really expect much from yours, but was
pleasantly surprised by its effectiveness.
Thanks for making such a good product!
M. L. from Michigan
Thanks for the quick delivery of the filter. I had it in place within 5
minutes of taking it out of the mailbox. It does a great job on the AM radio
station noise that I was getting on my phone and my modem. There was so much
noise that my modem would not connect to my ISP during the day. In the
evening when the power was reduced I could get connected but daytime hours
were impossible. Thanks for a product that works!
G. from Tennessee
----- Original Message -----
I would like to purchase a tel filter....but don't see any bottom cut-off freq, I would probaly use it mostly on 160 meters (1900 t0 2000 khz) and was wondering which filter would work best, the am or hf.
Thank you very much.
Thanks for the inquiry. There is some frequency overlap between the 2 filters. I need to display a graph showing the attenuation versus frequency for the AM-1 and the RF-1 but have not managed to do that yet.
The AM-1 works better for 160 meters. At 2 Mhz the RF-1 attenuates RF by a factor of 80 times and the AM-1 attenuates RF by a factor of 250 times at that frequency.
Whereas at 7mHz the RF-1 attenuates RF 200 times and the AM-1 attenuates by a factor of 100 times.
I avoid using dB figures because so many other filter manufacturers seem to exaggerate their dB figures.
John K. Browne
I got your filter today and it works better than any I have tried before. I have a Yaesu
FT-1000 that will put out 200 watts and at this range with your filter inline there isn't any interference anymore.
I am a soldier at Ft Sill Oklahoma. I've been reading a little about the rfi interference on the
telephone lines. My question is, Does the filter work on computers too?
When I key my HF radio transmitter, even at 10 watts, it will disconnect me from the internet and
sometimes even lock-up my computer. It's begining to be a pain!
Any help would be appreciated. Thanks.
Hey John,Just got the filter in the mail. WORKS GREAT!!! My video still scrambles slightly but at
least I stay connected, which allows me to send AMTOR over the radio and stay on the internet.
Thanks again for your help.
I live across the street from an AM radio station. On
our remote phones, our speaker phones and now on my new computer, I pick the station as if I
had a radio tuned in. We’ve lived with the phone problems for ages but now it is effecting the
speed of my modem transfers (drastically). I have one computer with a modem as part of the
sound card and it has worked well (the speakers are separate and external).
The modems (both internal and external) are receiving so much interference, it takes triple to
quintuple the time to transfer data. I’ve been told to find an RFI modem cable which I will try. But
the problem was just as bad or worse with an internal modem (which I returned thinking it was
defective). Any ideas???? Basically, I've been having problems getting connected as quickly as I
should, and when I'm online, any browser I use will usually "choke" on a simple page download
and freeze, forcing me to force quit it. I've covered all my bases with the modem, my OS and my
ISP, and all the techies I've spoken to point to my line quality. It would make sense that there be
CB interference because I live in a neighborhood in Brooklyn NY that has truckers stopping off
loads during the day. I suppose that they would be the ones using CBs as well as policemen.
Another reason I suspect line interference is that I sent a set of "atdt" modem commands through
my ISP number and usually get a line quality reading that leans towards "25". The ideal, I've been
told, is anywhere between 0-25. A couple of times I did this check, I got some very weird gobbly
gook in the text display--and this was when just dialing through this low overhead modem
command program. I suspect that the same gobbly gook is coming through when I'm at http
addresses online and crashing my browers. Basically, I'm at the end of my rope, and this is the last
resort, other than getting a pricy ISDN. Does this info help you out a little more? I look forward to
Thanks for the quick response sending the filter. It did the trick and my modem is back up to
speed once again. Thanks again for all your help.
I would like to begin by thanking you for you help. As you know we had serious RFI with an
ISDN line coming into the building. The problem occurred after the ISDN line exited the router as
an analog line. We tried everything, we thought (including other filters). We placed two of your
filters on the phone line (one at the router and one at the phone). They worked great!
Thanks again John for you support and good product!
John, The filter arrived on Friday and IT WORKS!! I also mentioned it on the air today and at least one of my buddies is also placing an order.
Thank you again - you've made us very happy.
John, I got the filter yesterday and installed it into my modem line. It works great. I can now run a
full kilowatt output when transmitting SSTV and I still remain connected to the internet.
It has completely solved my problem.
I still connect at 48kbps with my 56K modem so no degrading of performance.
Thank you very much for sending the filter. I really appreciate it.
Many many thanks for sending me the two RF-1 filters. They arrived safely and in good condition.
I installed them the same night and ran a few tests with the Kenwood TL922 linear running at 1200 watts........I was amazed, absolutely no interference either on my telephones or on my internet modem. I normally run only 450 watts, and before the installation of the filters, could not use my telephone / internet facilities, and talk on the air at the same time. I even had interference on the internet modem when running 100 watts.
Your product looks extremely neat and very professional, and I will from my side recommend it to all those here in South Africa who have similar problems.....and there are many !
Thank you once again for an excellent product, as well as taking the trouble to send it to me.
Is the radio enthusiast next door, or your neighborhood radio station, slowing down your modem and
jamming your telephone? Then, you may need a K-Y RFI filter.
I recently visited your website and wanted to ask a question about your Modem Filters. I have a phone modem and I am having an interference problem. I am pretty sure that the interference problem is coming from my neighbors electric fence charger. I can hear the fence charger's tic tic sound through my modem. When the fence charger is plugged up I cannot connect to the Internet, but when we unplug the fence charger my modem connects normally. Does your product stop this kind of interference? If not, can you suggest a possible solution.
Thanks for the inquiry. Our technicians tell us that the problem is caused by bad (corroded)connections where the fence wire sections connect together. The high voltage sparks or arcs across these places causing a very wide spectrum signal that our filters probably will not help. (You might be able to see the sparks, at night, in the dark)
The simple fix, short of soldering all these connections, is to paint across each wire junction with silver conductive paint.
I hope that this is of some help.
John K. Browne
Just thought you'd like to know:
New USRobotics 56k Faxmodem was unusable because of severe RF interference.
This modem replaced a Practical Peripherals 38.8 modem. User had complained
about connection difficulties, and unexpected hang-ups.
Your RF-1 filter fixed the problem COMPLETELY. Dialtone is clean and clear,
and we're getting connection speeds of 53.3.
What frequency range is covered by your telephone filter device?
I live 200 yards from an AM radio transmitter (1080 KHz) and the
signal infiltrates everything I own. :-)
Now I know you can't predict the results, because there are so
many factors involved, but will the choke in your filter be a good
filter for 1080 KHz?
Thanks for any info.
Thanks for the inquiry. Yes our filter works extremely well over the
whole am broadcast band (1080kHz). Also we have a money back policy if
it doesn't help your situation.
John K. Browne
Thanks for such a quick response. I ordered TWO. :-) Let's hope that
between the filters and some proper grounding, I'll be free of this radio
station from hell. :-)
Thanks for the order. We shipped your filters earlier this evening
(Monday) first class US post office. You should get them Wednesday or
Thursday. Don't hesitate to contact me if there is any problem or if you
have any questions. Thanks again.
They arrived today.
Simply amazing. The first quiet phone calls I've had in months. ;-)
Tomorrow morning will be the big test. I have some interesting ground loops
in the wiring/cable TV here that are worse when the sun comes up-- and since
the decoders also share this line, it will be interesting to see what
But so far so good! If they pass the morning test, I will likely order two
more for my neighbors.
-Jimbo (Santa Cruz, CA)
I just got your filter the other day, and it completely solved my
problem. I want to extend my thanks and regards for your wonderful
product. I tried everything, from adjusting the phone line to buying a
new modem, months of agony to solve this problem. The aspect that it
might be RFI never crossed my mind until I tried a few experiments until
the clues and suggestions from friends led to the suspicion that it was
RFI. The kicker was that the interference only happened upstairs in the
house (which you said might be because of the phone lines in the wall
acting like an antenna) and was time dependent, only occurring at
specific times during the day, and other times not.
So, when I plugged in your filter I was skeptical and a bit
fearful that it might not work, and was already tired of trying
everything else, I was happily surprised and delighted that it completely
nullified the interference. However, the only thing that I noticed was
that if it's positioned a certain way, the line signal doesn't go through
the filter all the way correctly, so you have to mess with the jack and
the plugs to get it to work sometimes, which is okay, as long as I can
get it to work again. That wouldn't be a defective filter would it, if
it only works in certain positions or are the connections just sensitive? Anyway, thanks for a good product that actually works. I
never knew anything about RFI until I stumbled on your site and fixed my
Thanks for the positive feedback. I'm glad it works for you.
It sounds like the connector is defective, however. I will send you a
replacement asap. It may take a few days to get there. Just keep the
defective one for your troubles.
John K. Browne
Can you help me? I was told that I must have a phone filter on my home
security system to receive DSL and to block the noise. I understand that
it's an 8 wire filter, much larger than a regulr size phone filter. Do you
have one? If not, can you please tell me where I can get one.
Thank's for your help.
Thanks for the inquiry! You might try the following url for the type of
filter that you need:
John K. Browne
That RF-1 did it! Before, 5 watts on 10 meters would
put the computer on the floor. Now I can watch the dx
cluster and run 500 watts and the computer just keeps
on humming along. Many thanks.
73 Waymon from Tennessee
On behalf of M. W., we would like to thank you for the filters
killed the RF on her phone.
The RF only appeared after I installed a headset with amp on her
2 line set. The set is on the second floor and I bypassed the attic
wiring with a
more direct and shorter run of wire to the basement with no difference.
tried using RG58 coax and Radio Shack's ferrites on the set cords with
I temporarily tried one of the filters on a phone with a built in AM/FM
radio in the
bedroom which has always had 2 AM stations booming in and they were
None of the other 6 phones in the house get RF.
I used to carry RF filters on my truck before I retired a year ago
occasionally installed broadcast circuits for the phone company. I will
get one of
those filters for the bedroom phone from my son who had one in place on
line when there was an AM transmitter in his area.
Thanx again. D.E.
I just wanted to write and tell you how pleased I am that your product exists. I was experiencing so much noise on my phone line that was preventing my fax equipment from receiving calls. It was actually hurting my business. Of course, the phone company was no help and claimed that my line supposedly passed their tests. On my own, I amplified the line and could hear a particular pattern of static that I suspected might be some kind radio interference. Not knowing what to do, I went to my local Radio Shack and purchased their “RF line-noise filter” with high hopes. Believe it or not, introducing this device actually made the problem WORSE. Instead of hearing varying static, I could then hear AM 640 coming through crystal clear on my telephone line.
Having discovered that it was an AM radio station that was interfering, I scoured the internet for a better filter. That’s when I discovered your product. After being discouraged by the failure of Radio Shack’s finest, I was a little skeptical of your filter. However, I still needed a solution and was willing to give it a try. What really sold me was that a customer in one of your testimonials actually mentioned that he also tried the Radio Shack filter and found that it worsened his problem too! This compelled me to believe your site’s claims and actually give your AM filter a try. Sure enough, it reduced the interference COMPLETELY! When I amplify my line now, I don’t hear a speck of static and my faxes come in at high speed every time!
Thank you so much!
A satisfied user of the AM-1 filter
just thought you might like to know. I installed the RF-1 filter at the line input on my answering machine, turned on my HF rig, did a broadcast on 75 meters, and bingo! No interference to my answering machine.
Thanks. There are a couple of other guys I can tell about this. Have a good day.
I recently ordered an AM filter from you and am thrilled at the results.
I wanted to write to say thank you!
My house is located 0.36 miles from an AM radio station that broadcasts
with a four-antenna array at 50kW (daytime) at 990kHz. I thought I would
escape the problem that others in the neighbor hood have with RF
interference by using a Voice over IP system instead of a traditional
landline from the phone company. In theory that was a good idea, but in
practice the VoIP interface box (Cisco ATA 186) is very susceptible to
RF. With one phone directly hooked into the ATA, everything was OK, but
as soon as I hooked the ATA to my house's phone wiring, the AM station
came through loud and clear even if no phones were hooked to any of the
extensions. It was apparent that the house wiring was acting as an
antenna and that the ATA was rectifying the signal. The small filters
the radio station provided had no effect, and I was very frustrated.
I was tempted to replace the house's 27-year-old phone wire with
expensive shielded twisted pair. I also contemplated buying an
expandable wireless phone system for about $250 that would have replaced
my hard-wired phones with mobile extensions. Neither of those options
were particularly attractive.
I am very glad I found your Web site using Google. Your AM-1 filter did
the trick. After I plugged it in, I couldn't believe how crystal clear
the phone became. It was certainly the best $28 I've ever spent on
Very truly yours,
S.S. Pennsylvania, USA
I was looking at your website and have a question. I just recently signed up for voice over
internet phone service and am having issue swith hearing a local AM station on my phone.
When I had landline phone service, I had absolutely no issues with phone sound quality.
I have a Linksys broadband router with phone ports now connected to my home phone
wiring system that is back feeding my house wiring through one of the wall jacks after of
course physically disconnecting my house from the previous land line service.
What filter solution of yours would you recommend?
JK from Michigan
Thanks for the inquiry. I am not really familiar with your setup. It
is possible that one of our AM-1 filters connected between the telephone
line and your computer may solve the problem (I am not sure what type of
connectors are used in your system. Our filters use RJ11 connectors).
If the AM-1 doesn't solve the problem, we have a money back guarantee.
I hope that this info is helpful to you.
I received the AM-1 filter today and immediately installed it on the phone cord between the telephone
adapter and the wall jack backfeeding the house wiring. It was just the ticket. Dead silence!
After the dial tone, I pressed the first number and dead silence. I had to check to see if something got disconnected.
I had a Radio Shack filter in-line which reduced the noise but definitely left alot to be desired.
Your filter was definitely just what I needed. I called AT&T before all this after signing up for the
CallVantage service (phone over internet), they wanted to charge me $135 for the service call if
they sent out a technician and found that the noise was not the fault of the telephone adapter
equipment they provided me for the service. Needless to say, the filter at $28 was money well spent.
You should call AT&T and offer your filter to them for resale.
Reading you FAQ's section, I came across the comment in regards to
AM and Radio Shack Filters. I live close to KOMO AM towers (AM
1000) in the Seattle Area and get heavy interference on my phone
lines. I have tried Radio Shack Filters and filters provided by
KOMO, all without success. Will your AM-1 filter work for the AM
frequency? I currently have 2 cordless phones, one answer machine
and one modem attached.
Thanks for the inquiry.
Yes, our AM-1 works much better at that frequency. The Radio Shack
filters work best on the higher short wave frequencies similar to
our RF-1 filter. Actually KOMO's frequency of 1000 KHz is just at
the lower edge of what is considered "short wave") The AM-1 is
designed specifically for AM broadcast frequencies and attenuates
1000 KHZ by a factor of a few hundred times.
Your situation is somewhat complicated by the fact that you have
some equipment connected that is powered from the ac lines.
Sometimes the interference comes in over the ac power line and it
may be necessary to filter the ac cord as shown at the following
I hope that this info is of some help.
I am relatively naïve re filters. I have dsl connection with dsl filters
that came with computer; they seem fine. however, I have problems on my
phone line. there is a spanish language station one block away. I have
one corded phone (radio shack) and one mobile phone both on same line. I
have to record a daily phone call for a work project -- recording to be
transcribed. When I added a radio shack filter to phone line it worked
some until I added dsl filter. I have a phone recorder hooked up to the
phone. I get interference across both phones, less on the mobile.
However, I do most recording off the corded phone. which filter and
configuration would you recommend. thanks.
Thanks for the inquiry.
The DSL filter is used to separate the DSL data signal from the telephone
I am not sure where you installed the Radio Shack filter. To stop interference to the telephone, it should go
between the DSL filter and the telephone.
The Radio Shack RFI filters do not filter very well at the AM broadcast
frequencies. I assume that the Spanish language is an AM broadcast station.
Our AM-1 filter works very well on that kind of interference. An AM-1
installed between the DSL filter and the corded telephone should remove the
Spanish language transmissions from your phone. If the telephone itself is
powered from the ac line cord, you may need to filter that line also.
Your situation is complicated by the fact that you have a number of devices
connected and also by the fact that some of them are powered from the ac
You may have to filter the ac cord going to some of those pieces of
equipment. A simple scheme for doing this can be found at the following
I hope that this information is of some help.
I purchased an AM RF filter from you approx. 3 years ago. I must say it has worked absolutely perfect for me up until about a month ago. The interference is back and it doesn't make any difference how or where I plug in the filter now. My surroundings have not changed in my office and I don't know of any changes in transmit power, etc. from the nearby AM radio station.
My question is do these filters fail over time? If so is it covered for replacement?
Any help would be greatly appreciated!
The filter contains a choke made of wire wrapped around a ferrite core. It is a very stable mixture. Nothing, short of a nuclear blast (extreme heat), will change the characteristics of the ferrite or the wire. Most likely, something in the phone wiring, external to the filter, is now rectifying the radio signal.
Rectification changes a radio frequency signal to an audio frequency signal. The RF filter will not filter out an audio signal. It will only filter out RF.
The most common cause of rectification is a bad or corroded connection. I have seen this type of problem solved just by tightening a screw connector at the offending terminal..
Another common rectifier is the lightening arrestor. The house telephone wiring has a lightning arrestor (spark gap to ground) somewhere in the system and these sometimes become fused or welded together from the static electricity and this makes a rectifier.
I can send you a replacement filter, if you like, but if it is what I say it is, a new filter will have the same problem.
I hope that this info is of some help.
Thank you kindly for your expert suggestions to correct my interference problem.
My apologies but I completely forgot my wife had added a printer/Fax/copier to the same business line downstairs about a month ago. After reading your suggestions above, I happened to think of that, unplugged it.... no more background noise/talking from the nearby AM radio station.
I suppose from reading some of the info on your website, the fax was the culprit.
Again, sorry to have bothered you. Thanks again for a product that actually works!
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