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Re: LF: RE: RE: DLF passive received with earth antenna

To: [email protected]
Subject: Re: LF: RE: RE: DLF passive received with earth antenna
From: Stefan Schäfer <[email protected]>
Date: Thu, 15 Jul 2010 10:14:23 +0200
In-reply-to: <BF4A524700075746A6467658DFC7102C51094D0E48@ICTS-S-EXC2-CA.luna.kuleuven.be>
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Hello Rik,

Assume, i will increase the wire length or electrode spacing to 1200m this will not only be a full size dipole for 137 kHz but on 9 kHz the area might become 480000 m^2. Then, 1,75 A is needed. Even that is not really easy. So it will stay a rather ineffective antenna, compared to the kite antenna. But it is an interesting field and i want to know how it works on 137 kHz and how it can be matched and so on ;-)

Maybe i will discover that the DHO level is even lower than -94 dB, than the effective area could be even more ;-) Or if the ERP of DHO38 is lower than 100 kW... We will see...

Tnx for taking part on the discussion :-)

73, Stefan


Am 15.07.2010 09:40, schrieb Rik Strobbe:

Dear Jim, Stefan, LF group,

BTW, if my guess of 5mV/m is correct, and the loop EMF is 44mV, the effective loop area would be about 18000m^2...

that sounds impressive, based on the antenna length (280m) the "hight" of the loop would be 64m.

At 9kHz the radiation resistance of a 18000 m^2 loop is a mere 8 micro-Ohm, thus a current of 11A is needed to radiate 1mW.

But as the penetration depth into the earth is inverse proportional to the square root of the frequency the effective loop area at 9kHz might be 29000 m^2, increasing the radiation resistance to over 20 micro-Ohm. What means that 7A antenna current is need to get 1mW radiated.

But even that would require many kW.

 

73, Rik  ON7YD
________________________________________
Van: [email protected] [[email protected]] namens James Moritz [[email protected]]
Verzonden: donderdag 15 juli 2010 1:40
Aan: [email protected]
Onderwerp: LF: RE: DLF passive received with earth antenna


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