You can buy approximately 1/8" thick Lexan (or polycarbonate) in 8x10 sheets at Lowes or Home Depot.. I cut it into 3/8" wide strips, using a small bandsaw and a fence. Other dimension Lexan sheets can be bought at U.S. Plastics or McMaster-Carr.
I have a stack of already-cut ribs (10" long x 3/8 wide" that would have to be drilled. If you just want a few to play with, verify that your QRZ address is good and I will send you some (8 or so?).. And, I have some factory-punched strips that are good for AWG 12 wire, 6 TPI.. I had to pay for those and order a 1000 to get them. 8-) If you want to try those, I need to get $10 for 4 strips (10" long x 3/8 wide x .090 thick). No charge for shipping. I have forgotten what size wire you were planning to use. I have found that my "process" becomes more difficult if I use less than # 12.. I have had good results using AWG 8, 10 and 12. And, you can get that wire at The Wireman.. Buss wire, solid copper tinned. BTW, with 1/8 or so thick stock, a 3/32 drill works good for #12, 7/64 will work for #10. I have lost my notes for # 8 but I would start with a drill size that is slightly larger than the wire diameter. Too large will work but too small will bind! You can stack the ribs together and tape them (I use wide masking tape, just about two layers, at each end). Then you drill all the ribs at once.. As you thread the wire through the ribs, wear some cotton gloves. Try to keep the ribs straight and evenly-spaced as you do the threading. I have found that if the wire starts to bind a small squirt of WD-40 along the rib will help. After the coil is threaded, position the ribs and run a bead of model airplane cement along the rib where the wire comes through. Do a rib, let it dry, then do another rib, etc.. until all four are done. I usually do both sides of the ribs to get a "firm" coil. Let's see: form size is usually 3/8 to 1/2 smaller than the desired coil diameter. I use a 2 5/8 coil form made from PVC pipe couplings to produce 3" diameter coils. It is pretty close. And, I wind the coil with moderate tension by passing the wire through a bench vise (padded with a shop towel). Figure out the number of turns and add about 10 per-cent to allow for expansion. So, when I wind a 60 turn coil, I actually wind about 66 turns on the coil form. If you need long coil leads, add a couple of turns.. You can always cut off the excess -- it's tough to add wire to the coil.. 8-) Hope that helps.. 73, Larry KQ4BY --- Brett gazdzinski <[EMAIL PROTECTED]> wrote: > Larry, > Where do you get the strips of plastic to drill > and pass the coil through? > > Brett > N2DTS > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf > Of Larry Keith > > Sent: Tuesday, January 02, 2007 1:19 PM > > To: 'Discussion of AM Radio in the Amateur > Service' > > Subject: RE: Coil Construction, was: [AMRadio] Fun > with 4D32's... > > > > > > > > > > > > Thanks Larry. > > How do you keep the spacing of the holes > > exact? > > > > I have a "homebrew" table that attaches to my > small drill > > press. The table > > has a fence and a stop. I use spacers (plywood > > strips)stacked against the > > stop. I drill a hole and remove a spacer, > reposition the > > work, drill a > > hole, etc.. > > > > > > Since the handbook says the antenna tuner is good > > for 250 watts of AM, I would need to at least > double > > the size of things, from the #14 at 8 tpi, about > > a foot or more long, to ? > > #10, or #8, or thin copper tubing? > > > > I have built coils using #12, #10, #8 and using > copper > > tubing, using the > > same construction methods. > > > > > > > > > > Balance is important, maybe hard to do with > > a home brew coil.. > > > > Why? > > > > > > > > I did not study the text, not sure if its supposed > to > > cover 160 meters, but if I built one, might > > as well include 160... > > > > You just doubled the coil size, if it wasn't > designed for 160... > > > > > > > > I know I will need to make some sort of coil > > form/support to achieve a good balance. > > > > Polycarbonate sheet.. Mounted on stand-off > insulators.. > > > > > > 73, > > > > Larry > > KQ4BY > > > > > > > > > > > ______________________________________________________________ > > AMRadio mailing list > > List Home: > http://mailman.qth.net/mailman/listinfo/amradio > > Partner Website: http://www.amfone.net > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:[email protected] > > > > ______________________________________________________________ > AMRadio mailing list > List Home: > http://mailman.qth.net/mailman/listinfo/amradio > Partner Website: http://www.amfone.net > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > Larry Keith 231 Shenandoah Trail Warner Robins, GA 31088-6289 [EMAIL PROTECTED] [EMAIL PROTECTED] 478-329-0030 ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected]
