Radio won't stop playing Christmas music

It's not coming from the radio. It's coming from the fillings in your teeth.

To make an FM ratio detector or discriminator, you need two diodes and therefore two fillings, probably on each side of your mouth. If you've had recent dental work, this is a possibility. Try gargling with something alkaline and see if the music goes away.

I didn't have any fillings, or I might have. There was also a 5 MW EIRP Ch. 55 and a 1.8 MW EIRP Ch. 64 UHF signal, plus about 100 250 W VHF high band & UHF two way radio transmitters. We were also in the path of a 4 GHz ATT microwave relay and had multiple UHF and microwave STL links aimed at the site. The only place I saw that was worse was the VOA Bethany plant (Morrow Ohio) with 10, 50 KW HF transmitters on various short wave bands. You could hold a florescent lamp inside the facility and it would light from stray RF. It's intensity changed, with the modulation of the various tansmitters. The only way to 'turn it off' was to stick it in a locker. :)

Snopes has never heard of 'Slope Detection'?

They were never in Korea...

Slope Detection was a necessary way of staying alive.

Snickers.

Jeff

Michael, I know you well enough to know you almost know what you're talking about, and you're /not/ a liar, but I find that hard to believe. How could the field strength be high enough to ionize the gas without also ionizing one's brain (or other bodily parts)?

By "mechanism", I meant what was going on electrically. How was the signal picked up, demodulated, and fed to the speaker at sufficient level to be audible?

Not necessarily. If he tilted his head, wouldn't he get slope detection from just one filling?

Weren't the ATT relays 6 and 10 ghz?

Well, I had the same experience while working at Mt. Wilson in the Los Angeles area.

A Bird Watt meter would typically read 3-5 watts by itself. Without being hooked up.

And yes, RF levels like that are why OSHA came up with with requirements for the "lead jump suit from hell".

Jeff

You didn't feel any tingling or other physiological effects?

Nope. be we always made it a point to get in, get done and get out as quickly as possible.

Jeff

No, you tilted your head to change the detection angle of the radio wave polarity, thus, getting bipolar detection.

Jamie :)

Ah, Bird Meters, I have a couple of those with the slugs.

Nice meters how ever, I could never understand their value over other meters that get the job done.

Jamie

Back when CB was the latest new toy I heard plenty of anecdotes about rigs with power boosters causing florescent tubes to glow when keyed.

When I was a kid me and a few lads raided the council tip (which didn't have any fence back then). We found half a skip of dumped florescent tubes.

Initially we got on our bicycles and used the tubes as lances in a jousting contest, but when we held up a tube under the National Grid 400kV pylons we found the tube glowed quite visibly as dusk fell.

We planted a small forrest of tubes in the mud under the overhead cables close to the railway line to entertain the late commuters as their train went past.

In the early days of 625line UHF TV quite a lot of British made TVs used slope detection for the 6Mhz FM sound carrier.

One example, back about 20 years ago, a friend on the Olympic Peninsula had an old Knight Kit tube stereo amp. It was able to pick up both KGEI near San Francisco (a religious shortwave broadcaster, specializing in Russian Language, who had a really strong signal in the 6 Mhz band) and the Soviet's "Woodpecker" over the horizon radar that used HF. His (long) speaker wires were probably a good half wave dipole at that frequency, and the feedback circuit provided a good path from the speaker wiring back to the low level input circuitry.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Slope detection works with some sort of frequency to amplitude conversion contrivance. That might be possible if Jimmy's mouth or head were a fairly high Q resonant cavity with the FM station on the filter skirts. If true, he should be able to open and close his mouth to affect the tuning. Perhaps lining the inside (or outside) of the mouth, or possibly the head, with aluminium foil might improve the Q and therefore the selectivity. Inserting a megaphone in the mouth might be useful for having others share the experience.

Resonant frequency of the human skull (about 400MHz):

Slope Detector:

Patented in 1929. Uses one or two diodes.

More on "cavity" detector technology:

Bird meters and other test equipment were pretty simple to use and calibrated to government standards. I used to repair and install public service communications equipment and the Bird was the gold standard.

High fashion RF protection:

Been there, done that. We had to use incandescent lights in the building under the NBC tower because the fluorescent lights would not turn off until someone kludged a 3 way wall switch to short out the lights when off. I had a bag of NE-2 neon lamps that would light up on some antenna connectors. These daze, the fillings in my teeth would hurt when I go up to Umunhum, Mt Toro or Hidden Hills. I recently had them replaced with UV setting cement, which hopefully will eliminate the problem.

Also, Bird wattmeters are not my idea of accurate. 5% of full scale at best. That means that if you use a 100 watt slug to measure a 25 watt transmitter, your actual power can be anywhere from 20 to 30 watts. What's inside:

I never can get an accurate VWSR reading on a broadcast mountain top because the reverse power from antenna pickup would never really go away. I usually have to throw in a BPF cavity between the antenna and the wattmeter to get rid of the broadcast leakage.