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LF: Re: Re: Radiation from loading coil causing difference in current at

To: [email protected]
Subject: LF: Re: Re: Radiation from loading coil causing difference in current at top and bottom?
From: "Dick Rollema" <[email protected]>
Date: Sun, 13 May 2001 20:54:11 +0200
References: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
To All from PA0SE

Andy, G4JNT wrote:

But these harmonic currents will upset your readings somewhat - where on a
scope trace is the RMS value of
a) the total waveform   and
b) the fundamental  ?

The harmonic currents will obviously be out of phase with the harmonic
voltage, and cannot exit the top of the coil so if they are indeed
entering
the coil base they must be completing their loop in the fields from the
coil
itself - the quadrature, non dissipative,  H or  E fields.  Very little
radiation field will be generated from such a small radiating element,
even
at harmonic frequencies.
The current into the coil,  displayed as the voltage over the resistor in
series with the coil, looked like a pure sinewave. So the harmonics were
only present in the transmitter output VOLTAGE, not in the current into the
coil.

73, Dick, PA0SE


>The output voltage of the TX  was somewhat distorted due to harmonics,
>showing up as some ripple at the positive and negative peaks of the
>trace but  the zero crossings were at exactly the same points as the
voltage
>over the resistor.
>Thus as far as  can be judged from oscilloscope traces voltage and
current
>at the bottom end of the coil were in phase.



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