AboutChris Bushman Expertise I have been an amateur radio operator for about 36 years.
Experience In real life I manage a small motion picture film lab in Hollywood. I've been a fireman, a teacher of English in Okinawa, a personal computer tutor.
I am an Advanced Class Ham radio operator using my originally issued callsign WB6EEQ. I have operated for extended periods of time from Okinawa (KR6FX & KR6OP), Texas (K5VXG), and Mississippi (K5TYP).
While in the Air Force, I was a Manual Morse Radio Intercept Operator.
BS Zoology, UC Davis
Member, Society of Motion Picture/Television Engineers http://www.smpte.org/ - Member, American Radio Relay League http://www.arrl.org/ - Member, Quarter Century Wireless Assn. http://www.lockport-ny.com/radio.htm - President, Zen Nippon Airinkai, So Cal Chapter http://ourworld.compuserve.com/homepages/Chris_Bushman/ - Member, Maltose Falcons Homebrewing Society http://www.westval.com/mfalcons/ - Alumni, American Brewers' Guild http://www.abgbrew.com/
Expert: Chris Bushman Date: 8/7/2007 Subject: Neighbor's Ham, phone and baby monitor radio
Question We just bought a house and our neighbor has a Ham radio. The antenna is probably 20 to 25 feet tall. There are three things we have noticed that might be linked to the radio. The first is our baby monitor was picking up an AM radio station. This has never happened before. We solved it by getting a digital baby monitor. I tell you just by way of back ground.
The second problem is our land line. We have standard phone service, no cordless phones. Our phones pick up the AM radio signal, with better clarity than most car radios. It is so loud, you can barely hear the person on the other end of the line. I know that the neighbor’s Ham is not broadcasting the AM signal, but is it possible his tower is amplifying the signal somehow? What can I do to stop it. The phone company said I needed a frequency filter, but the people at Radio Shack looked at me like I was crazy.
Finally, once in a while our cell phones get loud interference. This interference is not the AM radio like the other two. This is just a loud buzz. However, only the person who is at the house is impacted. For example, if my wife calls me while she is home and I am at the store, she can hear me just fine but I can’t hear a word she is saying because of the buzz. This has happened in the reverse when I was at home and she was at the store as well, so I know it isn’t a problem with one phone.
Any advice would be helpful. Thanks.
Answer Well, David, this is a puzzling one. None of the interference events that you describe sound like Ham interference. The only one that has possibilities is the third one, but even that is a long shot.
First off, it would be helpful to determine if your neighbor really is a Ham radio operator. Hams tend to be considerate and helpful in such situations. CB operators and non-licensed radio ops tend to be otherwise. Ask what his callsign is. If he gives you his "handle" he is a CB'er. If he really is a Ham, a friendly approach might result in him helping you solve your problems, even if he is not the cause.
AM radio is a very low frequency. The closest Ham band to AM radio is a higher frequency and that band is probably the least used by Hams. Chances are that your neighbor has never operated near that frequency (I did only once in 35 years). There is the possibility that you are somehow getting interference from an up-link from that AM radio station rather than their direct AM signal. Radio stations usually originate at a location in a city, then link to a mountaintop or tall building for the actual broadcast. Identify the offending AM station and then call them and chat with one their engineers. He may be able to shed some light on your situation.
The land line problem may be resolved with an EMI (Electro Magnetic Interference) filter or an RFI (Radio Frequency Interference) filter - almost the same thing. Talk to somebody else at Radio Shack. They may also call it a low pass filter. There is a big discussion of it at... http://www.arrl.org/tis/info/rfitel.html
Sorry about some of the Ham specific language.
The cell phone problem sounds like interference from a household power source. Usually the "buzz" is 60 Hz the same frequency as house current. A nearby power transformer can be the problem as well as dozens of local possibilities like somebody welding in the neighborhood or a faulty power supply from any number of non-radio things.
Ham interference usually sounds like garbled mumbling. It starts and stops just like normal human communication and has an up and down pattern. It only happens during active Ham communications, not just because there is an antenna nearby.
There is the possibility that your household electrical system is not properly grounded and this could be causing all your problems. Perhaps a $75 housecall from an electician and a $20 grounding rod is all that you need.
Obviously, this is a complex problem. If you think that I might be able to help some more, please don't forget about that "follow-up question" button.
