[Elecraft] Practical toroid winding question

[Vic Rosenthal]

Mike wrote:

> I am almost ready to start winding toroids for my K2.  I have run into this
> question before but never found an answer.

> Suppose I wind a toroid, then check its inductance afterwards.  I find that
> the value is not exactly the same value as the schematic calls for, but after
> removing one turn (or adding one turn), it's perfect.

> Should you,

> a)  use the # of turns in the assembly instructions, regardless of the value
> obtained, since the designer knows a lot more than I do

> b)  change the number of turns, since the performance of the radio is based
> on the value of the inductance


The correct answer is a).  One of the things the designer knows is that the 
inductance of a toroid varies with frequency as a result of the characteristics 
of the core material.  So unless you are measuring the inductance at the 
appropriate frequency, your measurement may not be correct.

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco