Sam & other BITXers
Your measurements explain my results then. Instead of tap/faucet
washers I used 1/4 inch slices cut from "1/2 inch" PVC pipe (the
schedule-40 or medium-thick-wall type). These measure about 13/16" OD
and 5/8" ID.
In my BITX20 I followed Farhan's instructions regarding the nunber of
turns and my coils came out nearly perfect for inductance value.
I just wound a second set of coils using the PVC material and
facilitated the winding process by cutting a slot in the plastic
former. This means I did not have to thread the wire through the core
150 times. These new coils check out on the dip meter as also being
on-the-money for inductance.
It is interesting that these "air-core" toroids exhibit some of the
same characteristics as ferrite cored units. My dip meter does not
get a strong coupling to the coil itself unless I add a coupling loop
through the core. I thought that phenomena was due to ferrite
channeling the magnetic field, but maybe the shape of the coil has
more influence than I thought.
Arv
_._
--- In BITX20@..., Sam Caldwell <samc@x> wrote:
Hans Summers wrote :
...in which G0UPL travels to his local hardware store to further
investigate
the nature of the infamous tap washers, and in particular the
differences
between ordinary and "delta" washers.
Both are know as 1/2 inch tap washers but both measure more than
1/2 inch
(12.7mm). As close as I can measure with my ruler:
As I understand it, the " half -inch' refers to the bore of the water
pipe with which they are associated - and includes three-quarter and
one-inch as part of the series.
A typical "half-inch" tap washer in the past would measure perhaps
three-quarters of an inch dia., but in more recent times the
proliferation of fancy bathroom ware has given rise to a variety of
custom taps (faucets) with their own washers.
My own houshold taps ( I'm told ) have ceramic washers which ( I'm
told ) never wear out and ( I know ) are drip-free.
Regards, Sam C.
ZL1TOI
