Re: LF: Loading Coils

["M. J. Powell" <mike@pickmere.demon.co.uk>]

In message <01C4CE0F.A626D2D0.actalbot@southsurf.com>, Andy 
<actalbot@southsurf.com> writes
> 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!
They did in my school, as a check on the calculation. But I went to 
school during the war, and was taught by teachers who had retired before 
the war and came back to replace those called up. WW II, of course!
Mike
--
M.J.Powell