To: qrp-l@mailman.qth.net Subject: [QRP-L] FYBO From: "Steve L." Date: Fri, 4 Feb 2005 09:48:06 -0800 (PST) Reply-to: n4sl@yahoo.com List-post: W7MRG will be active as a field/alternate power/multi-op station from Arlington, WA for the duration of FYBO '05. Ops: WB7FJG, N4SL, NU7J Rig: K2 with internal ATU, external balun Power: 5Ahr 12V gel cell. Ant: 88' center-fed doublet, few with open wire line. Height will be about 70', strung between two tall trees in a park, shot up with a bow & arrow. I have found the modeling of the 88' cf doublet to show excellent characteristics on 40,20,15 (and I'm sure 30 and 17 as well). Planning on a near-100% CW event at 5W. I made this antenna especially for QRP field use (camping, /Bumblebee, FYBO, etc) from extremely light weight materials: Wire for antenna and feedline: 26 AWG 19-strand copperweld, purchased from Davis RF. This wire is very lightweight yet extremely strong and flexible with an excellent insulation. I highly recommend it. Bottom of this page, their PN "POLYS-26" http://www.davisrf.com/ham1/flexweve.htm I used 1/4" black irrigation tubing for the spreaders. Drilled a 5/64" hole with 1.5" spacing, then threaded them onto the wire. No glue or other attachment required. Yes, this takes some time but the finished product is GREAT! I spaced the spreaders about every 10" on the line. For the center insulator, I cut a scrap piece of Lexan, drilled holes at 1.5" spacing and soldered ring lugs onto the feedline and antenna wires. Using SS wingnut HW, this assembled/disassembles easily in the field into three pieces, making it easier to store and also to install in the field. I fill the ring lugs crimp area with hot melt glue for strain relief. End insulators are small pieces of 1/2" PVC cut and drilled. Simple, cheap. I use a cheap-o plastic extension cord spooler to spool the feedline and antenna wire onto, making unspooling a tangle-free event. Think "Christmas tree string lights" here, same thing. I'd like to hear what other materials/techniques/antennas the portable QRP crowd is using, this one really fits the bill and is just so lightweight and simple. 73, Steve N4SL