Re: THOR resonance freq. measurement results

["Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Tesla list wrote:
> 
> Original poster: "Metlicka Marc" <mystuffs-at-orwell-dot-net>
>...
> i would also add that though the trans. line frequency of 60 Hz is
> prevalent at say 4' above ground, that at say 2" above ground i mostly
> have seen 8 - 30 Hz. this being in the range of the freq. of the earth.
> i will also state that my measuring technique is not at all high tech.,
> just using my fluke 87 III and a small cordless phone antenna that i
> keep in my bag. but i get consistent readings from it and have even
> accurately measured the frequency of  ac motor drives by holding the
> antenna around the load wires of the drive and checking my readings
> against the displayed output frequency of the drive.
> any input on this theory?

Certainly you see 60 Hz everywhere if you make high impedance 
measurements. Any frequency meter with high input impedance shows 60 Hz
if you connect open wires to the input, and any oscilloscope will show
a 60 Hz waveform if connected in this way. An useful technique
to see if oscilloscopes and amplifiers are working is to touch the
input connectors. You serve as an antenna, and injects a 60 Hz signal...
Care to avoid interferences is essential in any measurement.
The interference is greatly reduced in low-impedance measurements,
or with use of shielded cables and filters. A last resource is 
to make an spectral analysis of the obtained signal, and ignore 60 Hz
and close harmonics as 120 Hz.

Antonio Carlos M. de Queiroz