Light bulbs that produce spontaneous FM band RF oscillations

[ChrisSmolinski]

Rustika lightbulb FM measurements

http://www.radiomuseum.org/forum/rustika_lightbulb_fm_measurements.html

Referenced from: http://www.rexophone.com/?p=1081

Mr. Sousa first links to Hans Hollmann’s 1935 description and analysis of the phenomenon.  He then adds his own description of what is happening inside the light bulb, noting that the effect is not unlike the action of Klystron radio frequency oscillator tubes.  Once bulb makers coiled the filament and replaced vacuum with  inert gases, light bulbs stopped oscillating.  Mr. Sousa then goes on to describe his own experiments using reproductions of these straight-filament tungsten bulbs (yes you can get working reproductions of certain antique bulbs).  He collects some impressive documentation of the radio frequency characteristics of these bulbs.  Then he does something quite amazing—he impresses an audio signal and modulates the radio carrier emanating from the light bulb—actually using the bulb as a radio transmitter!  That’s so cool!  Mr. Sousa uses a scanning radio receiver since the light bulb’s radio carrier drifts as it gets warmer.

[ka1iic]

Mr. Sousa...

Oh I love his march tunage!!!

I've seen Edison bulbs oscillate but never heard the carrier...  Did I miss something?  Must be...

[Pigmeat]

When CFL's of this type first became common, there was an article in a ham mag about how to use them as an experimental QRP transmitter in the lower CW range of 80 meters. The guy went in depth with details on how to do it, then ended with a caveat, this should only be attempted by experienced hams for authorized experimental stations, as it wasn't legal to use and they would throw spurs up and down the band w/o very good filtering, and then it could be iffy.

My reaction on reading it was, "Why print it at all? You've just put out a step by step plan on how to build your very own wideband noise generator for every prankster on the planet." Sometimes those hamsters amaze me.

[Josh]

When CFL's of this type first became common, there was an article in a ham mag about how to use them as an experimental QRP transmitter in the lower CW range of 80 meters. The guy went in depth with details on how to do it, then ended with a caveat, this should only be attempted by experienced hams for authorized experimental stations, as it wasn't legal to use and they would throw spurs up and down the band w/o very good filtering, and then it could be iffy.

My reaction on reading it was, "Why print it at all? You've just put out a step by step plan on how to build your very own wideband noise generator for every prankster on the planet." Sometimes those hamsters amaze me.

Lol reminds me of chucking a 100ft piece of wire with a silicon diode in the middle of it in some bushes near a miscreant swlers house. The rf from all the local tv, fm, and am stations made for fun listening around that block.

[Pigmeat]

I'll have to remember that the next time I visit Cousin Al. He likes figuring out puzzlers like that one.

Besides, the batteries on that regen locked on 6925 kHz in his attic ran out months ago. I knew I should have tapped into the electric lines.