At 11:33 AM 7/27/04 -0600, you wrote:
Hi,
I got given some poly square plastic stuff and thought hmm I could use this
in a loop somehow and this popped into my mind I am thinking 15 inches on
the outside with wood and the lengths on the inside holding it together that
poly square plastic stuff is 1/2 inch square. So that would make the loop
14.5in square not huge but decent I figure. I was thinking of bringing the
coupling loop in about an inch or two from that so the coupling loop would
be 13.5in or so to 12.5in not sure which is better. was going to make the
"plate" to hold the cap out of lexan and the "plate" for the connections
back to the receiver. question is how many turns of wire for the AM BCB I am
sure there is a calc for this but I haven't seen it and I wanted to share my
design. Also the rest wood be made from wood the longer pieces.
Scott
KC7WDG
My second post. I took a look at your construction schematic. U are using 4 pegs sandwiched between 2 frames. My construction is similar but different. If you look at your schematic cross section (from the side) ... I have just one frame and the pegs are mounted with 1 screw each to only one frame. The other end of the peg is free. The frame I use is simply a plywood sheet (a plexiglass sheet and pegs would be classy). I mount my capacitor in the center on the opposite side of the sheet from the winding. I screw one end of a 12" peg on the same side of the sheet as the winding. I then slide my coupling coil (8" dia. 3 turns) along this peg for optimum coupling.
I mount the whole thing vertically on a 8" square block which acts as a base. I glued a sheet of velvet material on the bottom to avoid scratching the HiFi set.
For normal listening on the HiFi I just slide the pickup hoop right in the loop .... nothing critical. When I am dxing with another receiver I find the coupling adjustment is invaluable.
Jim Dunstan
Thunder Bay, ON
