[Elecraft] Toroids

[Edward Kenworthy]

That's great, thanks Don and Tom.

Edward

On 7/7/03 10:00 pm, "Don Wilhelm" <w3fpr@peoplepc.com> wrote:

> Edward,
> 
> This subject comes up from time to time on this reflector.  Inductance
> meters seem to vary all over the place depending on the variety.
> Inter-winding capacitance and many other factors will have a great influence
> on many meters which makes them frequency dependent.  You likely do NOT have
> a problem.  You could double check the core type you actually used and
> recount the number of turns (count the wires through the center of the
> toroid rather than the turns on the outside).  I will believe the inductance
> tables published by Amidon before I believe my inductance meter for all but
> very low frequency inductors.
> 
> If you used the correct core material and put the number of turns specified
> by Elecraft on it, then it will work in the intended application - ignore
> your inductance meter readings.
> 
> You generated a bit of my curiosity though by your timely question - I am
> building a K2 for another ham and he ordered the toroids from 'The Toroid
> Guy', so I pulled out the ones for the noise blanker and put them on my
> inductance DVM adapter - nothing fancy, the one that has been in the ARRL
> Handbook for a few years - measures at about 60 kHz. -  L1 and L2 measured 2
> uH and L3 measured 123 uH - go figure!!!
> 
> 73,
> Don W3FPR
> 
> 
> 
> ----- Original Message -----
> 
>> I decided to take a break from building the main K2 and thought I'd build
> a
>> couple of the options, so I built the noise blanker. I wound the three
>> toroids and thought I'd done a pretty good job - right number of turns,
>> pretty tight, reasonably well spread over about 85% of the toroid. So
>> imagine my surprise when I measure their inductance. So the two toroids
>> shown as 1.2uH actually measured as 4uH; whilst the 40uH toroid measured
> as
>> 80uH.
>> 
> 
> 
>