Bizarre things you have experienced with RFI and the like

[rrsounds]

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At WGBF we found transmission line problems with a flourescent bulb having no power to it. The line was 6 outer wires (copper) and a single ijner conductor (copper). The old Collins 5 kw had transformers that would sing. Lovely to hear the audio even with no radio. Erwin told me never to walk inside the rf cavity (transmitter energized) with keys in my pocket as the6ywould get hot and I would run screaming out of the cabinet with hot keys. Unless ofcourse I electrocuted myself on the way out.
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During my brief tenure as a technician for WNBC 660, in 1986, I went with Engineering Supervisor Gary Blau to familiarize myself with the transmitter site on High Island, in Long Island Sound. As many here know, that facility (now WFAN) was and is co-located and antenna-diplexed with WCBS, 880, both stations clear-channel 50kW ND.

My most lasting impression was the tuning house: as you entered, on your left was the tuning network for 880, loudly brap-brapping with the sound of voices from the News station. On your right, was the (somewhat) tuneful singing of music from the coils and caps of WNBC. Very cool! Especially impressive to this new New Yorker, since the ATU was nearly as big as the apartment I had just rented in the East Village, LOL!

About the only thing that maybe impressed me as much, was looking at the tower's huge base insulator out back, and thinking just how much voltage was sitting on it, with only a small fence separating me from eternity.

Kind Regards,
David

 

[Kmagrill]

I've also heard singing/talking coils on several 5kW AM stations. WRUF-AM has a 4 tower DA and the phasor tended to do that.

A fun thing to do was to slide a 4 foot florescent light tube between the grounded chain-link fence and daytime non-DA tower 1 (without actually touching the tower, of course) and watch the portion between the fence and tower light up brightly. It always impressed the engineering students from the university that came by for a look.

 

[RadeoEngineer]

About 100 years ago I was down in Rosarito Beach to assist in some work being done on the directional antenna system. Tower #6 was not used in the daytime, but had to be grounded to keep the RF from two 50kW AM's located within a mile from burning the tower crew. I'll never forget the first time I saw RF arcing from a "cold" tower.

 

[WNTIRadio]

I've got a 5kW AM that lights up the florescent bulb in the tuning house for tower #2 at day power, and the coils sing quite nicely.

At another 2.5kW AM, the wire ladder over the transmitter provides confidence monitoring sans radio.

It's a fun trick to hold up a 4' florescent light bulb and wave it around like Darth Vader to impress your friends...

 

[rrsounds]

I've also heard singing/talking coils on several 5kW AM stations. WRUF-AM has a 4 tower DA and the phasor tended to do that.

A fun thing to do was to slide a 4 foot florescent light tube between the grounded chain-link fence and daytime non-DA tower 1 (without actually touching the tower, of course) and watch the portion between the fence and tower light up brightly. It always impressed the engineering students from the university that came by for a look.

Small world, Kyle...I was a transmitter engineer (babysitter) at WRUF's Quonset hut for a few months in 1975. I went around the corner to WGVL-FM to do mornings in October of that year. Not soon after, a freak tornado brought down three of WRUF's towers, (plummeting the FM antenna deep, deep into the earth!) and severely damaged the fourth.

Kind Regards,
David

 

[Kmagrill]

The one old Windcharger tower from the 1940s to survive that tornado is still standing today. It took 3 years to fully repair the ground system after the collapsed steel was removed. Lots of digging and brazing of wires went on and on and on...

The quonset hut is still there, but you would not recognize the inside, David. I was there last year for the first time in about 25 years. The old control room was partitioned into rental spaces and the University transmitters ended up in the 1960s fallout shelter. But I digress...

One interesting aspect of the site was watching lightning strike the towers and never taking any damage to the AM or FM. There was also very little problem with RFI there. That's when I realized that proper ground design could eliminate many of these common problems.

I do recall one engineer's car headlights would flash with modulation when he parked at the hut. I've never seen anything like that again.

 

[boiseengineer]

I've seen windshield wipers start up when parked under an FM tower (280% of occupied limit before the antennas were moved). Snowmobile that would die at the same site because the RFI would kill the electronic ignition. Learned where not to park or you'd have to drag the sled around to find a place it would run.

 

[Chuck]

There is a public park in Ceder Hill, TX, that is within "spitting distance" of several very large TV and radio towers. The stray RF pretty well wipes out most automotive keyless entry devices. I've experienced this personally on a 2001 Chevy Suburban. People don't seem to know what to do when this happens, but the obvious answer is "use the key."

 

[DTV-Chief]

There is a public park in Ceder Hill, TX, that is within "spitting distance" of several very large TV and radio towers. The stray RF pretty well wipes out most automotive keyless entry devices. I've experienced this personally on a 2001 Chevy Suburban. People don't seem to know what to do when this happens, but the obvious answer is "use the key."

I can't use my '05 Jeep Grand Cherokee's keyless entry in the parking lot at WEAU TV Studios and thus forced to use the key, but then the alarm goes off and only way to silence is to climb in and start the vehicle (while everyone nearby wonders what's going on).

 

[boiseengineer]

Not unusual at the ski area http://www.bogusbasin.org/cam_data/tubehill/video.jpg where the towers are located to have cars in the parking lot randomly turn on their alarms. The first season their new quad lift was running they had to do a lot of RFI fixing. The chairs would randomly start stacking up at the top. Rode the lift up that winter with parts for the BE. After I got it up to full power went to leave & discovered the quad lift was down. Got a ride with the ski patrol that day.

Bad snow year. Still can drive to the site!

 

[WNTIRadio]

I have a friend who lives in Meridian, last time I was there we drove up in April and there was still 6 feet of snow on the ground. Pretty impressive site though, looking down on the entire valley all the way out to Oregon. I'll bet even a 10 watt translator is a blowtorch from that height.

Next time I get out there I'll have to bug you for a tour!

 

[OKCRadioGuy]

I know of a certain 50kw station that will light up florecents from about a hundred feet away. It'll also induce so much voltage in an unfeed STL tower that's detuned on the property that it actually arced across a huge insulator they originally installed. Not only does the coils and stuff sing, but so does the fence. The ground near the daytime single tower is warm because of all the juice going through it. RFI for miles and miles away from it, especially at night in it's main lobe...

 

[K4WRF]

I know of a certain 50kw station that will light up florecents from about a hundred feet away. It'll also induce so much voltage in an unfeed STL tower that's detuned on the property that it actually arced across a huge insulator they originally installed. Not only does the coils and stuff sing, but so does the fence. The ground near the daytime single tower is warm because of all the juice going through it. RFI for miles and miles away from it, especially at night in it's main lobe...

I wonder if that same station might be the one that has about 125 (or perhaps more) OG&E power poles detuned????
w/

 

[OKCRadioGuy]

Hi Watt. Yup. That's the one. I also hear that some of those detunes near the station get awfully warm if you reach out and touch the upper wire. In fact some of them will produce one hell of of a spark and RF burn from what I've heard :0

 

[K4WRF]

Hi Watt. Yup. That's the one. I also hear that some of those detunes near the station get awfully warm if you reach out and touch the upper wire. In fact some of them will produce one hell of of a spark and RF burn from what I've heard :0

Chasing that thing *was* tantamount to running a "fools errand"! Long, long story with more turns than Sherlock Holmes novel...

 

[OKCRadioGuy]

Certainly not the easiest pattern to try to keep in either with build-out of power lines in the area...

 

[LA_Guy]

When I worked for WHDH 850 in Boston MA, my GM got an RFI call from a VERY nasty woman about 5 miles from our site and well out of our blanketing contour. She had called the FCC, her Congressman, etc. BEFORE calling the station. He asked me to go there and I did-and there was a lot of RF in her wall phone in the kitchen and also in the living room phone. After unplugging the living room phone, I put a filter on the kitchen phone and found very little difference, so I asked her if there were any more phones upstairs. She told me no but I insisted to look and she relented. When I got into the master bedroom I saw a piece of quad (total length about 50 feet) coming from the cable box around the perimeter of the room and disapperaring behind the bed. Pulling the bed out from the wall revealed a phone jack hanging out of the wall with the red wire (JUST the red wire) of the quad connected to the screws on the back of the jack. It was obvious that the green wire had broken off. I cut the red wire (great antenna huh?) and all the RFI on the phones downstairs was gone. Why didn't I simply hook up the green wire? Because she had been such a jerk to my boss, that's why! I got out of there and didn't even bother to remove the filter I had installed in the phone jack in the kitchen. I never heard a peep from her again.

 

[chrish]

WQIK 1090 Jacksonville 50 KW could draw a hell of an arc off the nails in the fence around the tower perimiter.

 

[Kmagrill]

WAJD, 5kW at 1390 has a 120' tower due to proximity to an airport. The unshielded, cinder block, building is 10' away from the tower base. Because of the short tower and close proximity, RF in the building is so high that if you stand inside the equipment rack and touch the top of it, you can draw a hefty arc. Yes, there's ample 4" strap bonding everything to the radial ground. The site eats transmitters for lunch. Other than the original Gates BC5P, nothing has stayed on the air for more than a few weeks at a time. It's the only site I ever saw where an Optimod 9100 was too overloaded by rf to function. A Gentner Eagle worked well instead.

 

[RadioFan2J3]

It has been reported there was a double engine failure of a blimp passing by A Site at VOA-Greenville a few years back.

http://www.cvel.clemson.edu/pdf/nasa-rp1374.pdf

About 40 years ago, I was home on leave from Vietnam doing some work at the radio station in my home town in east-central Georgia. I was told that at night, or perhaps early, just before morning sign-on, there was interference from another radio station in the console.

I stayed up over night one evening at the station and discovered RF interference on one of the turntable channels, the audio being endless newscasts programming. Seems the TT preamp was picking up what I later determined to be one of the shortwave AFRTS broadcasts no doubt out of Bethany, OH. Interestingly, the TT preamp didn't have any problem from the 1 kW being radiated from the tower less than 50 feet from the TT.