R.F. Interference and the CB Operator   

Striking the balance between enjoying a hobby to the fullest, and keeping your neighbors from killing you.   


I've covered many of the positive aspects of the CB radio hobby in past articles.  Now it's time to take a look at one of the more painful aspects of having a radio hobby that involves transmitting signals - Radio Frequency Interference, or RFI.  Sometimes known as "TVI" (Television Interference), I prefer the term RFI as it is more generic and applies to devices other than televisions.  What RFI is, in essence, is the reception of an unwanted RF signal on a device that isn't designed or intended to receive it.

Radio operators would like nothing more than to have their signals leave their antennas, and only be heard by other radio operators, in whichever areas they intend to talk. But reality being the imperfect entity that it is, means that along with those intended reception areas, oftentimes your signal will also get intercepted by nearby electronic devices owned by your neighbors, including some devices which were not intended to receive radio signals at all.  Interfering with their passive pleasure is often the beginning of what may ultimately become a mutually contemptuous relationship.  They eventually learn to resent you for disrupting their entertainment.  You resent them for constantly complaining about your hobby and feeling obligated to limit your enjoyment just to keep the peace.  Unless a swift and total solution to the problem can be identified and implemented, your relationship with your neighbor(s) will eventually deteriorate until the point where legal (or illegal) action is attempted.  It's really a shame in cases where the two (or more) warring parties used to be friends, or at least mutually respectful, before the discovery of your radio hobby, or the neighbor buys a new toy which is susceptible to interference. 

 There are many books and much information on the internet dealing with the subject of RFI and what steps you can take to cure or minimize it.  It's true that dirty transmitters can cause problems.  But in most cases, it's not the transmitter which is at fault. Rather, it's the inability of the consumer device to reject RF ingress in the presence of a strong RF field, such as what surrounds a radio transmitter's antenna, that causes the most grief.  But in many cases, there is only so much the radio operator can do on his end to help the problem.  Running lower power, not running "hacked" up radios or class "C" amplifiers, using low pass filters, proper impedance decoupling at the antenna, and running good RF grounds will go a long way to ensure that the signal you radiate is clean.  Sometimes, careful selection of antenna types and how and where they are mounted will minimize that near field signal concentration, which is the cause of most of the consternation.  But once you've done all these things and the problem still persists, there's really nothing more you can do on your end (other than not transmitting at all, which is not an option).  And this is the place where you don't want to be.  It's always far better to be able to change something simple on your end (like changing to a better antenna and raising it 30' higher), and solving the problem, because you are in control.  If you do what you can and the problem is still there, it means that the solution will have to be implemented on the neighbor's end to his equipment, and that's a dicey prospect.  First off, no one wants to hear that the spiffy new $3000 high def TV, or 5.1 surround sound they just bought is a piece of junk.  It's far easier for them to simply blame you.  So consequently, your neighbor may not want anything done to his stuff.  His attitude may very well be that your transmitting is the root cause of the problem, and you should simply stop doing it.  That's a bit unrealistic, but if that's the way he wants to be, it's his choice (See mutually contemptuous relationship above).  Secondly, if you do "something" to his stuff, even if it solves the interference problem,  and then something breaks a week from now, or 20 years in the future, he will blame the malfunction on what you did, and expect you to pay to have it fixed.  Sometimes you might get lucky and live next to a reasonable guy who will agree to attach filters to his stuff (and if you offer to buy them, it may make it all the better).  But in some cases, you may have to try several things to resolve the problem. It could be a high pass filter on a TV or stereo with external antenna.  It may be an A.C. line filter, or shielded speaker wires.  You also have to face the possibility that nothing you can do will completely eliminate the problem.  In this case, you have 3 basic choices.  You can give up your hobby (or transmit from a mobile only), which I'm sure would not be your first choice.  If you really LIKE your neighbor, you can buy him a new device which you've tested to not get this type of interference (which I'm sure will make him a much friendlier guy).  Or finally, you can go the route of mutually contemptuous relationship and prepare to get to know the locals cops on a first name basis (having coffee and donuts at the ready might be helpful) and maybe the local window and tire shops as well.  Sometimes a compromise can be made.  If your neighbor only listens to a particular radio show at 6:00 on Sunday nights, I'm sure you can be quiet for the next hour or two.  On the other hand, if he hears you while he watches prime time TV every night of the week, you start cutting into a much bigger chunk of your limited hobby time (was that a knock I heard at your door?).

I first became aware of the phenomenon of RFI in 1973 when I discovered that my TRC-99 3 watt walkie-talkie could be heard through my old tube "Hi-Fi" record player/AM radio when I transmitted right next to it.  Not being able to "bleed" through the broadcast radio with my 100 mW walkie-talkies, this phenomenon soon became a sign of "power".  When I got my 1 Watt Midland,  W-T, I checked that it too could be heard over the broadcast radio which I figured meant that it was probably "getting out" fairly well.  That was probably the first and last time that a case of RFI was seen as a "good" thing.  Once I got a full powered 23 channel radio and outdoor antenna, my near field signal expanded dramatically. The first "complaint" that I got was from my next door neighbors, good friends of my mother and the parents of my friend "Spud", who also had a brief fling with CB in the mid 70's.  They matter-of-factly told my mother that they could hear me coming through their bed table clock radio when they went to bed at night.  This was only a problem on non-school nights when I was allowed to stay up later.  As the months wore on I slowly heard other reports of my signal being heard in places where it shouldn't.  One was another friend and also one of our original pioneering kids CB group on Channel 14, who lived across the street.  He had an "El-Cheapo" stereo, which he could hear me loud and clear through, unless he disconnected the speakers and used headphones.  Things could only have gotten worse in 1975 when I got my first 75 watt amplifier, which had the potential to further increase my RFI potential.  Strangely, I really didn't hear much more other than third hand accounts from people who knew people, who supposedly could hear me or I put lines in their TV.  I always suspected that I was interfering with more neighbors but they chose to remain quiet about it.  No one ever showed up on my front door step accompanied by an angry mob with pitchforks and flaming torches.  So my radio hobby continued throughout the 70's, although I started getting a little self-conscious that I might be overheard on some as-of-yet unknown neighbor's radio or TV while I was in the middle of a heated argument, or was otherwise not in a "G-rated" mode.  The last thing I needed was to give an old lady a heart attack while listening to her nice soothing radio show, and it was suddenly interrupted by one of my song parodies or some other off-color comic schtick or slapstick nonsense.  I also thought it was strange that I could cause interference to devices hundreds of feet away, while I didn't bother any of my own stuff.

In 1982, I had my most serious issue with RFI.  The neighbor directly across the street (himself ironically a former CB'er), replaced his ailing bedroom TV with a new one, and he immediately started hearing me blasting through the speakers.  He accused me of "changing something" on my end, or running "heat".  Yet he either couldn't or didn't want to see that the only thing that had changed was his new TV.  I guess when you fork out a sizable chunk of change for something, you don't want to accept that it's faulty in some way.  It was far easier for him to try bullying me around.  But being the radio geek that I am, I couldn't miss any of the local radio drama for even one night, so limiting my prime-time talking just wouldn't work.  Eventually the situation escalated to the point where I got a letter from the FCC over the issue.  But fortunately (for me), I responded with my ham station call sign and when they found out it was a ham station involved, they washed their hands of the situation.  The problem ended when my neighbor got divorced and moved out.  Hopefully his new digs weren't near any radio operators.

Throughout the 80's the incidents continued to pop up as new and ever more cheaply made consumer devices debuted on the market.  When cordless phones became popular, yet another source of heartburn for both me and the people who owned them reared it's ugly head.  I was told that I could be heard on a cordless phone a whole 6 doors up the street, while running stock, legal power.  When I started listening in on cordless phone conversations, I overheard more than one conversation where my antennas (both CB and ham at this point), and the interference they allegedly caused, were discussed at length.  It was also interesting in a "paranoid imaginations gone wild" sort of way to hear people speculating whether I was a spy, whether my antennas could cause cancer, or if I could get HBO for free.

Probably the last known (to me) case of long term RFI from my old station occurred in the 90's. The neighbor behind me on the opposite street, evidently could hear me coming over his stereo.  This situation lasted until I finally moved out of my old neighborhood in 1999. Interestingly, for all the years that this was going on, I never had a face-face, or direct telephone conversation with this guy. The first time he complained, it was to my wife when I was out.  She sweetly told him, that there was nothing she could do and that he should come back and talk to me (which he never did).  Then some time later,  I got a call from a "ham friend" of this guy who wanted to work as a sort of "subject matter expert" mediator to try to resolve the situation.  But he adopted an attitude which assumed that I was doing something wrong and that the interference was due to my equipment being faulty.  However, I was no dope when it came to radio,  and most of my counter-suggestions involved attaching filters to the offended stereo, and running shielded speaker wire etc.  The "ham friend" could not get me to change anything on my end (which by now I had a spectrum analyzer to prove that my transmitters were clean), so he gave up. Then for the longest while, I heard nothing, and if it weren't for hearing the neighbor bad-mouthing me to his friends over his cordless phone, I would've assumed that the problem had been solved.  But since he had such nice glowing things to say about me, I decided it was time to screw with him.  I started messing with his phone when he was talking (See this article for details on how). He also had one of those motion detector lights on his back porch, which are very susceptible to RF interference.  I found out that if I cranked the power up to about 100 watts on 6 meters, I could make that light turn on.  So I used to blip it on randomly just to see him look out the back door to see what invisible critters might be trespassing in his yard (he he).  The joyous day for my neighbor, and any others still plagued with RFI, came in November of 1999, when I pulled up stakes and moved out. Problem solved!

I half expected the neighbors to throw a big party the day after I moved out.  The source of their RFI angst was finally gone.  While I didn't have all that many actual complaints, it stood to reason that if one or two people were having issues, that there would be others. Many of my neighbors were older people who really didn't want to become confrontational, and they probably kept it to themselves, especially if it wasn't all that bad.

When I moved into my new location, I was starting off with a clean slate and I really didn't want to have RFI problems again. I had one thing going for me this time, the homes were all new and the utility lines were underground thereby eliminating one big source for RF ingress.  But despite all that, I did manage to have one complaint.  My next door neighbor, who was probably the only guy left on the planet who still watches TV with rabbit ears for an antenna, had a problem with interference on his TV.  I was running a ground mounted omni-directional antenna at that time, and since then, I've gone to a direction beam antenna, mounted about 35' above the ground.  I haven't heard any more complaints, and when February of 2009 rolls around and all analog TV goes the way of the dinosaur, that should be the end of it for good.

I'm sure my situation is not all that unique. I've had other radio guys lament about their own RFI issues, and the radio forums on the internet are always bustling with questions about it.  I'm sure that RFI is one reason why newer home developments have specific prohibitions on transmitting antennas. It's really a raw deal too. While there are some irresponsible CB operators out there who run trashy hacked up radios and way too much power, most of the time, the RF interference issues are due to manufacturers electing to forego good engineering practice when it comes to effective shielding, in order to shave a few bucks off of their B.O.M. cost and add to their profit margins.  Considering that the percentage of people having to deal with interference from radio guys is relatively small, it's probably a good business decision.  But it puts us radio guys at odds with the gadget-crazed general public, and we're severely outgunned. A little diplomacy can go a long way in this case. It's probably a good thing that I only operate a couple of nights a week these days.......