> On Thu, Dec 18, 2003 at 12:44:18AM -0800, H.C. Croon enlightened us > thusly > > > On Fri, Dec 12, 2003 at 09:19:27AM -0800, Torelli, Bruce enlightened > > > us thusly > > > > > > > > I remember reading an instruction placard for leak testing an old > > > > microwave years ago. All you needed to do was pass a small 5"-6" > > > > florescent tube near the door parting surfaces. The tube would > > > > supposedly glow if there was leakage. I never tried it. > > > > > > It does. The technique is commonly used in RF generators > > > (13.56/27.12/41.xx Mhz). But at that frequency, you need a > > > considerable amount of power to light the tube at all. You don't > > > believe it until you see it, but I have seen it. If that much > > > microwave power was excaping, your eyeballs would be cooked before > > > you could see if it was lighting :-/. > > > > > > The RF generators are one big tank oscillator made from a power > > > triode thermionic valve, and used for rapid curing of glue and > > > plastic welding. They suddenly went a bit scarce after CE approval > > > ... > > > > > Hi Declan, > > > > I doubt. Having a fluorescenct tube for p.e. 8W for full light, a > > fraction of a Watt of power would suffice for local illumination at a > > lower, but observable, light intensity. I remember stories of people > > living in the neighbourhood of broadcast antenna's. The fluorescent > > tubes in their houses were lighting spontaneously. They were not > > cooked! > > I for one would certainly not remian in a house where bulbs lit > spontaneously! > > Broadcasting can be at nasty frequencies.
The frequencies involved where 500-2000 kHz In this country there was > regular enough trouble with mobile phone repeaters, and investigations > are being done about the unusually high cancer rates in the locality of > Electric Power pylons. When word got into some small villages that a > local mast or tower was to get a mobile phone repeater, they simply > picketed the area in such force that the installation was prevented. > Others were installed by night, and subsequently vandalized or removed. > > I personally did the bulb experiment with a 2.5KW RF generator, and an 8 > inch tube. This generator had a valve with 4.5KV on it passing 0.56 amps > or so (2.52KW). The current was read on an A.C. Ammeter. I had the side > off. The output was wide strips of flexible brass leading to two sides > of a clamp about 18 inches long, which were for clamping plastic > sheeting. This output was of course capacitor fed, and the frequency > was 13.56Mhz. > > With the jaws open, and the generator on (maximum voltage swing) I could > get no visible light from the inside of the generator or the brass > strips. When I put the bulb parallel with and close to the clamp jaws, I > did get light. That seems to indicate a fair deal of power was required > to light the bulb. The visibility is not only light, but a change of > colour to a yellowish shade of light. Subsequent tests on Plastic > indicated the generator was up to normal power output. > > I am told likewise that larger bulbs (or some section of them) also > 'light' in the presence of rf, and think the effect on the gas of the > particular frequency is a factor that cannot be ignored That's likely to be an important aspect. Thanks for your fast response, Best regards, Harry -- Author: H.C. Croon INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
