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Re: [Amps] measuring rf colis

To: <amps@contesting.com>
Subject: Re: [Amps] measuring rf colis
From: Scott Townley <nx7u@arrl.net>
Date: Tue, 24 Jan 2006 18:31:00 -0700
List-post: <mailto:amps@contesting.com>
Probably at low-frequency...like 1kHz or so.
Remember the RF devices will measure a coil's *apparent* inductance, 
meaning inductance together with distributed capacitance plus any stray 
capacitance to ground.  Typically the apparent inductance will increase as 
one approaches the first self-resonance (which is parallel in a solenoidal 
coil) and then decrease past that, nearing zero at the first series resonance.
Terman (Radio Engineers Handbook) shows how to do lots of fun calculations 
on coils and self-resonance.

At 17:51 2006-01-24, Partain, Chuck wrote:
>probably touched upon 10k times but..
>
>Using my MFJ-259b, measuring some rf coils I have here, sweep the frequency...
>all coils I have, move all over the place. Is there a standard frequency 
>these are rated at?
>
>say a coil is advertised at 10uh. at what frequency? I can pretty much 
>determine the current
>by the size of the wire...??
>
>chuck
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