Dear all,
I have heard of a case that a german LF amateur had ruined his
capacitance meter because of a static loading on the aerial!
Therefore I have always preferred to measure aerial capacitance by
checking the detuning effect of the aerial to a tuned circuit. The coil
of this circuit will always ground the aerial for dc.
HW?
73 Ha-Jo, DJ1ZB
"John GM4SLV" <[email protected]> schrieb:
>
> Rog,
>
> That's an interesting idea - I've never thought of trying a digital Cap
> meter. I must try it on the new antenna - and compare it to my homebrew
> RF bridge, calculations and - more telling - to the valuse of L I
> eventually need to resonate it.
>
>
> John GM4SLV
>
>
> On Wed, 1 Aug 2007, GW3UEP wrote:
>
> > Re ant cap: you can use a DMM [Rapid 328] to gnd - I use 1000pF across
> > its terminals to decouple RF for a stable reading. Simply subtract its
> > value. 73, Rog.
> >
> > ----- Original Message -----
> > From: James Moritz
> > To: [email protected]
> > Sent: Wednesday, August 01, 2007 12:05 PM
> > Subject: LF: Re: newbie help
> >
> >
> > Dear Paul,
> >
> > In a nutshell:
> >
> > - You can tune up more or less any bit of wire for reasonable results
> > on 500kHz. For best results, make it as high up as possible, and
> > secondarily as long as possible. An HF long wire, or dipole with
> > feeders strapped would be fine.
> >
> > -Work out the capacitance of the wire (see formulas on ON7YD's
> > antennas pages). and calculate the inductance for resonance around
> > 502.5kHz. For most HF-sized wire antennas, this will be of the order
> > of 100s of uH. The resulting coil is
>
>
>
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