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Re: Terry's New Plane Wave Antenna

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,
It is well known that coils tend to charge up the surroundings negatively due to the fact that negative voltages arc "easier" than positive ones. Ie, mercury arc rectifier.
However, the plane wave antenna does not see frequencies below say 15Hz so and DC or near DC signals are lost. Typically, with the scope on say 10uS/div and AC coupling, that low frequency cutoff is effectively much higher still. Richard was using either an electroscope or field mill which is certainly sensitive to net DC charges unlike the antenna.
Also, the arc effect is independent of the E-fields involved, so perhaps the antenna would not care anyway. I have never seen any net charging on the antenna's or anything "odd" going on like that.
It is interesting to wonder what the charging of surrounding objects does to streamer propagation. If the surroundings had a high negative charge, negative streamers would be suppressed and the positive streamers would be helped. But the only area that really counts is at the streamer head where the effects might not be so great do to the low impedance streamer path.
I suppose one could make a fairly large "array" of little antenna's with suitable shielding so that an x-y grid of voltage could be measured like a crude video CCD array. Each antenna really only needs the load capacitor to make it complete. Typical CMOS IC switches could switch and scan the load capacitor voltage array at a high speed to produce sort of a 2-D "picture" of the voltages. Of course, processing all the data from such a thing would be messy. But a DRSSTC is repeatable enough to reduce the scan rate to minutes if needed... Indeed, the area could be studied "bang to bang" in that case... 

Cheers,

        Terry


At 08:18 AM 12/23/2005, you wrote:

> Original poster: Ed Phillips <evp@xxxxxxxxxxx>

> "The capacitance between the coil and the antenna and the capacitive
> load form a voltage divider. The voltage is directly proportional to
> the coil's secondary voltage."

> i think that what you said above is correct only in the vacuum, coz in
> the air there are such things  like "ion cloud", "rectification" and
> maybe other even more funny stuff"

>     I agree completely, except in the case where there is no
> ionization and no streamer activity.  Otherwise it's highly possible
> that the real distance from the HV point to the pickup plate is much
> less than the distance from the top terminal of the TC.  For example,
> consider the case where a streamer "almost touches" the plate.

you don`t really need any ionization or streamer activity at all, and
especially you don`t need the extreme, when streamer "almost touches"
the plate - read what Richard Hulll said in '96:

"I have just recently sent out a single ping only from a resonant system
(under 15 watts) and recorded a negative dc potential level (NOT A
PULSE!!!) deposited on a 12" ball at a distance of 10 feet.  The volatge
stored on the ball was on the order of 4 volts.  The columbic charge was
~ 10^-9!  That's a net figure of ~10^8 or more electrons!  This voltage
is stored DC and must be discharged from the ball.   Ions?  Not likely.
Life span of the classic ion is too short (milliseconds at most) and the
mean free path too short for a virtually instananeous pulse to pile up
that charge.  There was no normal ion cloud build up time either as with
a coil just running."

"Using an electrometer, I have detected rapid negative charges on
balls up to 30 feet away.  This is pointing to non-ionic tranfer.  Up
close, like you detected, ions are the main factor and supply real
power as I have noted and you have confirmed.  I have found that my
little 20 watt coil can charge a cap with an effective DC impedance of
about 100,000 ohms."

-----
Let the bass kick! =:-D