Arvid Evans <arvevans@...>
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.
--- In BITX20@..., Sam Caldwell <samc@x> wrote:
Hans Summers wrote :investigate
differencesthe nature of the infamous tap washers, and in particular the
1/2 inchbetween ordinary and "delta" washers.
(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