"Roy Lewallen" wrote in message
...
amdx wrote:
. . .
My questions still stand,
Question 1
How many gausse is used to measure permeability and set AL?

Essentially zero.

Ok, So I'll use the figure of 1 gausse as where permeability is measured and
from there I can assume the inductance increases 40 percent at 2000 gausse
for the toroid specified on the Magnetics webpage. The only info I have is
from
Ferroxcube Soft Ferrites and accessories 2000 data book, and it simply says
"The initial permeabilty is measured------ at a very low field strength."

Question 2.
Can anyone take a stab at how many gausse in a typical FT140-43 toroid
with 8 turns on the secondary, and 34 or 35 turns on the primary used on
a
flag antenna with a low level signal.

I won't bother to calculate it because the change in permeability would
be so small you wouldn't be able to measure it. This is a non-problem;
you're wasting your time worrying about it.

I'm not worrying, just curious, since I've been using a large potcore to
deliver microwatts that at one time I used at near a kilowatt. Just
wondered
if we were losing some low frequency response because of a change in
permeability. It seems as though the permeabilty measurement is made nearer
the power levels of our receive antenna signals.


On the second question the material can be modified to reflect the
material
and turns as needed.

If your circuit is sensitive to a change in a few parts per million of
permeability, it has serious problems. The permeability will change
several orders of magnitude more than that with modest changes in
temperature.

Roy Lewallen, W7EL

Thanks Roy,
I appreciate the discussion and information.
Mike