Hi Paul,
it sounds like your impedance bridge is measuring the absolute impedance
(that is Z = (R^2 + X^2)^0.5 where R is the real part, resistance, and X
is the imaginary part, reactance). R is probably a 10 to a few hundred
ohms, most of it is ground resistance - it can be neglected - the major
part of your impedance is the capacitive reactance of the antenna (Xc).
At 9 kHz, where C = 1/(2*Pi*9000*Xc), 70 kOhms means 253pF which is in
the ballpark for your 170' wire (about 5pF/m).
73
Johan SM6LKM
----
Paul A. Cianciolo wrote:
>
> Hello All,
>
> Below is a quote from the Stefan's web page concerning his latest "Dreamers
> Band" DX contact Congratulations again Stefan.
>>From this information alone is it possible to calculate or know the antenna
>>system impedance.
>
>
>
>
> "100m Vertical wire antenna, coil/antenna voltage was abt 15kV rms, average
> antenna current about 480mA, giving up to 1,7mW ERP. Applied power was up to
> 250W."
>
> Pertaining to the coil "Technical and mechanical data: L=553mH, Q=82,
> R(DC)=283 Ohm; 0,4mm diameter enameled copper wire, about 1200 turns! Average
> diameter 0,55m, height abt 0,5m. So, about 2000m wire! :-)"
>
>
>
> I have built a small impedance bridge that operates at 10 KHZ and shows my
> sloping 170' wire as 70K Ohms. I can also see approx 500 PF that can be
> nulled out using the bridge?
>
> Can the 70K value possibly be correct? (3) 6' ground rods about 6' apart
> are the ground... plus the electrical ground of the house.
>
> I am hoping to attempt a local transmission on 9KHZ
>
> Any information would be helpful.
>
> Thank you
>
> Paul
>
> W1VLF
>
>
>
>
>
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