From: "Barton B. Anderson"
Date: Wed, 31 Oct 2001 00:06:45 +0000
Subject: Re: [TSSP] EMI measurements
Yea Finn, I too was stunned! I've been playing with antenna's lately seeing just how loud I can get with a few simple cb toys and when I saw the decible levels, my mouth dropped open and my brain has been twirling wondering how to pipe that power intelligibly as another comm toy. It is really amazing to "know this" but I guess it's not overly surprising considering our primitive coils are still "primitive". It does help one understand why sparkgap transmitters are banned. Take care, Bart -- Barton B. Anderson http://www.classictesla.com "Terrell W. Fritz" wrote: > Hi Finn, > > Rest assured, we are still all alive and very interested!! > > Lot going on this summer/fall Robot wars (I played last Sunday with > mine*), I got a new Sun workstation Computer today (yes Paul, that is a > real UNIX 64 bit Computer! :-))) I got it to celebrate the introduction of > Windows XP :-))), Halloween, work classes... Darn busy!! > > * > http://hot-streamer.com/temp/Pa030021.jpg > > In this case of your data, we just look at it with our mouths open > speechless :-)) When you post something and get no response, it means one > of two things. Either no one cares, or we are all too stunned to answer. > Rest assured yours is the latter :-)) > > I was surprised that the emissions were so broadband. Way up into the > 100's and 1GHz region (maybe higher too!). It may help a bunch to use big > ferrite beads around the spark gap. Mine has ferrites on the rotor and > stationary electrodes: > > http://hot-streamer.com/TeslaCoils/MyCoils/BigCoil/Rgap.jpg > > Much more thought is still needed on this!! > > Cheers, > > Terry > > At 04:02 PM 10/28/2001 +0100, you wrote: > >Gang! > > > >I posted this info to the pupman list, but for some reason it did not > >seem interesting. > >However, I think that the first public measurements of a Tesla coil`s > >electromagnetic radiation just has _got_ to be interesting, so in the > >light of this lists longlasting quietness, I allow myself to break the > >silence and tell you: > > > >That the Museum coil was run for some length of time, and the emission > >was recorded by an appropriate Rohde&Schwarz instrument (yeah! I forgot > >to write the No. of the instrument down, but it was as big as a baking > >oven). The antenna was a fancy one too. > > > >I don`t know if there is any need to discuss this much, but I want to be > >sure that this is being noticed by you who are able to picture the > >consequences of the fact that an operating coil is a broadband > >transmitter, starting out 70dB too loud at 30 MHz and continuing to be > >40dB too loud at 1GHz. > > > >The coil during measurement: > >http://home5.inet.tele.dk/f-hammer/measurecoil.jpg > >To give you an idea about the power level that is being used.(345K) > > > >The antenna: > >http://home5.inet.tele.dk/f-hammer/antenna.jpg > >(345K) > >The emission files: > > > >http://hot-streamer.com/temp/Hor_10m.doc > >http://hot-streamer.com/temp/Ver_10m.doc > >http://hot-streamer.com/temp/BG_Ver_10m.doc > > > >For more information about the museum coil, go to: > > > >http://home5.inet.tele.dk/f-hammer/tesla/tesla.htm > > > >Cheers, Finn Hammer
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.