Re[2]: LF: Loading Coils

["John Rabson" <word.factory@zetnet.co.uk>]

On 19/11/2004 at 08:13 Andy wrote:

> When it comes to calculations, the most useful ability is not to be able
> to 
> caculate it exactly, caculator or no, but to quickly be able to estimate a
> ball 
> park answer or approximation.
> Who needs to know that  22uH at 137kHz has 18.93 ohms reactance.
>
> Its quicker to think  " a bit more than 20 times a bit less than 0.14,
> times 
> 6-and-a-bit
> ...    is  2.8 times 6-and-a-bit ,  so call it 18 ohms"
>
> And they don't teach that in schools - and never have done, to my
> knowledge!
>
> Andy  G4JNT
I seem to recall a telecommunications professor (Ken Cattermole?) who expected 
his MSc students at least to have a feel for whether a result was of the right 
order of magnitude.

John G3PAI