Oscillating Light Bulbs

Oh man, this is some fascinating stuff: old light bulbs found to be oscillating at VHF! Wayne, VA7AT, stumbled upon this phenomenon at age 13 while engaged in Knack activities. Now Joe Sousa explains the physics behind the emissions that caused Wayne's light bulb to interfere with the broadcast of baseball games. How long until AA1TJ has one of these bulbs on the air, making contacts? There is much in this that would appeal to Michael: light bulbs, weird physics, translations from German... You gotta love the BNC connector plugged directly into the bulb. Check it out the radio museum article here.

Hi Bill

There was a question posted on Antennex E-mail discussion group talking about how a vacuum type light bulb will oscillate and radiate RF at about 100MHZ. This answered the question I had since I was a boy of 13 experimenting with a light bulb in series with an electrolysis bath (aluminum electrodes with table salt dissolved in water) and 117vac. The bulb dimmed with the electrodes apart and at a certain position the radio I had on blanked out with fissing sound. I had to shut down the experiment quickly because the neighbors were listening on their favorite baseball game and cussed loudly .

I now know what happened on that fateful day. Here is a site I found about the oscillating light bulb http://www.radiomuseum.org/forum/rustika_lightbulb_fm_measurements.html

Wayne VA7AT

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Sputnik Rigs Cross the Pond, Cambridge to Cambridge

The Chief Designer, Michael, AA1TJ, alerted us to this wonderful post on Roger, G3XBM's blog:
http://g3xbm-qrp.blogspot.com/2011/09/sputnik-across-atlantic-today.html
We clearly see the spirit of the International Brotherhood of Electronic Wizards in Roger's comment: "Nice to think that valves used in missiles aimed at each other in the Cold War end in bringing friendship and joy. CW is a wonderful mode if you want simple equipment capable of DX." Indeed. Well done!

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Google, Supernovas... and DRAKES

I liked this ad for Google, but I now have the urge to decapitate my garden shed. Check out dad's Drake gear. Late in the clip you can see some beam antennas on a tower near the house.

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ALL the Bell System Tech Journals -- FREE!

Thanks to Dave, N8SBE, for alerting us to yet another tech treasure trove:

http://www.alcatel-lucent.com/bstj/

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Earthquake Video -- From Atop the Washington Monument

Check it out. This gives you an idea of what the August quake was like (albeit from a perhaps the scariest location):

http://youtu.be/BgHC2qREslw

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2-B Trouble Continues

Thanks for all the suggestions and encouragement. I agree with WA6ARA that the bandswitch is a likely suspect. For the E socket on the Drake 2-B (that's where my 22 MHz rock goes) the bandswitch switches in not just the crystal, but also a slug-tuned coil. It is presumed to be an overtone crystal.

The receiver works fine on all other bands.

I've already hit the wafer switch with several shots of RadioShack Contact Cleaner (I'm out of De-Ox-It). And I've given position E a good work out. No joy.

I will dig deeper this week.

It may be the crystal. It looks like I got it from Drake -- it is marked "22 MHz 2C" so it may be for the 2C receiver. It has a sort of worrisome dent in the side. I may build the test oscillator that Steve recommends.

Of course, as soon as I get this fixed the sunspots will disappear and 17 will become a white noise generator.

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2B Trouble!

So this morning I hear that the solar flux is up around 190 and the higher bands are coming back to life. I turn to my trusty Drake 2-B and turn the band switch from "40" (where it has been parked for quite some time) to "E." E is the position that kicks in the 22 MHz overtone crystal on the 6U8 local oscillator. I eagerly turn the pre-selector to the area where the 17 meter band used to appear and... nothing. Nada. Silence. No band noise. Nothing.

I thought the 6U8 might be going a bit soft. I swapped it out. The problem remains. I twisted that E band coil from one end to the other. Nothing. I cleaned the bandswitch contacts. No joy. Now I'm thinking it is the 22 MHz crystal. But its kind of strange for a crystal to just suddenly go bad... It worked before. The receiver is working on all the other bands, so the problem is really that the oscillator just won't go on 22 MHz.

What do you wizards recommend?

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