From: mystuffs@orwell.net (Metlicka Marc)
Date: Mon, 25 Dec 2000 23:38:42 -0500
Subject: [TSSP] early idle testing
all, after i bought my fluke counter/tracer on 9-10-00, i decided to try my hand at doing some resonance measurements and such. i really didn't know what i was doing but i thought i would post my notes from some of the interesting things i saw. (please don't laugh to hard), i mostly was amazed at the proximity effects as you will see. first off, i used my 10-1 ratio secondary, 21g wire wrapped 42" on a 4" pvc form. in my setup i connected my signal generator to the base. to the top of the coil i connected channel one of my scope and channel one of my counter. (these are my uneducated notes as i wrote them down at that time with questions to myself) generator settings:45khz, 1/2 amplitude, square wave, 1/3 offset counter settings: .1s, cycle rate inc.= 1/2, mode=cont., slope=+, ac, atten.=x1 scope settings: .5 v/cm, time/cm=1us, sensitivity = 1/2, trig.=1/2, ac, mag = x1 putting 45 khz in base fed i see 87.34 khz output at top, moving my hand into the bottom of the coil the frequency starts to rise, at 2" from coil freq. raised to 120khz. moving hand into center of coil causes a proximity type reaction? starting from aprox. 8" out, raising freq. up to a max of 210khz at a distance of 7" ? seemingly the field balloons out in a slight football shape? the waveform looks almost like a sine wave but the strange thing is that the wave is made up of small spiky caricature in the form, almost like a sine wave of 210khz that is made up of a very much higher frequency in itself (i drew a picture here), very strange. why does close proximity of hand raise frequency? metal rod placed in field creates same effect, max frequency rise is at 4" from center, 236khz falling back to 87khz when closer? raising signal to 50 khz input, effect falls off. increasing to 80 khz gives 132khz out but the prox effect extends out to 16" with a max rise of 300khz at 12"? i apologize to any that find this to be absolute nonsense because after i did these and other tests terry informed me that i was going about it all wrong. i just thought i would post these notes in case they may be of use or may spark an idea or two? i duplicated these results on three separate days after taking the setup apart and resetting, just to check my ability to duplicate my results. this was the start of my interest in measuring the parameters of the tc and am looking forward to doing much more testing on the several unique coils i have. i have cleared my testing area in my tesla room as best as i can so far, the cleared area dimensions for the space are 9' x 11' x 7' floor to ceiling. i have moved my pole pigs as close to the corners of the room as i can so if some can offer suggestions to measuring techniques, as paul has, i will start getting info for the list and project. also if anyone has experience with the ESI 250de impedance bridge operation or a place where i can get a manual, i could use this info. this LCR has very nice features that may offer valuable data and is battery operated for clean measurements, some features are- Q parallel, D-Q series also external input terminals for DET, G, D-Q, bias. i have worked with it quite a bit and am learning fast and now feel confident on my measurements. i also have checked it with some very accurate L standards, R standards and C standards that i have and could use. i would very much like to help but i know that it is hard to try to explain to a newcomer principles and techniques that most already know so i will understand if it is just easier to leave it be and i will go on on my own. thank you all for your kindness and time. marc
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.