[Elecraft] AADE LC meter for ham radio

Tom Hammond n0ss at earthlink.net
Fri Jan 27 13:29:43 EST 2006


Stephanie, et al:

VA3UXB wrote:
>>  I  used it quite a bit while building my K1 and K2, to verify the 
>> values  of some of the hard-to-read caps, and verify the values of 
>> the  toroids I was winding.

K2VCO wrote:
>The measured inductance of a toroid depends on the frequency at 
>which it's measured because of the characteristics of the toroid 
>material.  I don't know the frequency used by the AADE unit, but if 
>it's far from the operating frequency of a particular toroid, the 
>results might be misleading.
>
>Elecraft has said that they do *not* recommend meauring toroid 
>inductance, just winding the specified number of turns.
>
>If you must measure the inductance of a toroid, it would be better 
>to use something like an antenna analyzer which will allow you to 
>select the frequency at which the measurement is made.

HEED Vic's comments here. It's all too easy to become MUCH too 
wrapped up in the 'accuracy' of being able to measure component 
values, esp. those of the toroidal inductors you wind, and to become 
MUCH too anal about winding 'for' the published value.

Checking the values of FIXED components (resistances and 
capacitances) is not a bad thing, to confirm that the fixed-value 
component you hold in your hand is within the expected tolerance for 
THAT component... and the confirm that you actually picked up the 
component you think you did.

With hand-wound inductors for Elecraft rigs, FOLLOW THE MANUAL!

   1) Ensure you're using the specified SIZE and COLOR toroid
   2) Ensure you're using the specified wire color and size
   3) COUNT your turns! Each time the wire goes thru the core,
      that's ONE TURN
   4) Spread the turns out around the core, generally to occupy 80%
      to 85% of the available core.
   5) Ensure that you have the leads well stripped and tinned, and
   6) Ensure that the leads are installed into the proper holes in
      the PC board.

If you feel the absolutely overwhelming 'need' to measure the 
inductance of the toroidal inductor you just wound, do so with the 
intent or at least confirming that the value is 'within the 
ballpark', rather than being right on the money! IT'S NOT THAT 
CRITICAL, and you'll drive yourself nutz trying to 'hit' the 
published value... and for no significant benefit.

73,  Tom   N0SS

Fresno CA
>http://www.qsl.net/k2vco
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