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AW: [TCML] COUNTERPOISE



Dear Matt,
I just see, I alredy got the answer from you, re less efficiency of foil,
you said, it is the eddy current phenomen. sorry, I was not alert.
Fritz

Betreff: Re: [TCML] COUNTERPOISE

Abends Fritz,

    I only see a few possible problems with a  long cable to ground:

1. A long cable will tend to induce RF currents into any wire it  passes
parallel to.
2. A long cable might act as a "bias resistor" to keep the base of the coil

at several thousand volts above ground potential. This is especially bad if

you have one side of the primary connected to the base of the secondary. If
the
 primary is "floating" then it is not so bad.
3. Streamers will tend to "target" this cable for ground strikes.
4. With a well-designed counterpoise, it isn't necessary.

In terms of eddy currents, the least efficient counterpoise is a foil disk,

next best is a wire mesh disk, and best is a large number of wires  laid out

in a "wagon-wheel" pattern with the coil at the hub.

Matt D.



In a message dated 7/23/2008 12:19:26 P.M. Eastern Daylight Time,
fritz@xxxxxxxxxxxxxx writes:

Dear  spark afficionados,

Supposed we have a counterpoise as HF  "earth"   and also a not very good
conventional earth rod  connection available (supposed long cable, too high
impedance, too dry  ground etc.), woud it be a advantage, to connect this
"not so perfect"  ground post earth to the counterpoise-? Or should this
better not be done  for some reason?
Or looked from other end, can a not very satisfactory  earth post HF ground
be improoved with a additional  counterpoise-?

(It is understood as was explained in earlyer postings,  that the
counterpoise shall not be connected to the house mains earth, so  this is
not
the object)

Thank you for a answer,   Fritz


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