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Re: LF: Re: Re: newbie help

To: <[email protected]>
Subject: Re: LF: Re: Re: newbie help
From: "Paul Tomlinson" <[email protected]>
Date: Thu, 2 Aug 2007 18:29:34 +0100
Delivered-to: [email protected]
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lol
----- Original Message -----
From: GW3UEP
Sent: Thursday, August 02, 2007 10:17 AM
Subject: Re: LF: Re: Re: newbie help

I discharge it thru' the xyl first.
Rog.
----- Original Message -----
Sent: Thursday, August 02, 2007 7:54 AM
Subject: Re: LF: Re: Re: newbie help

Good point Ha-Jo. When using my antenna impedance analyser, I always leave a
50 ohm load in parallel with the antenna, using a BNC T-piece. Only when the
antenna is connected do I remove the 50 ohm terminator, that way hopefully
any static on the antenna is discharged through it.

73
Tom G3OLB

----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Wednesday, August 01, 2007 11:20 PM
Subject: Re: LF: Re: Re: newbie help


> 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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