I’ve wanted to build a ladder-line dipole for a while now. Last summer during field day, my partner Steve constructed a brilliant one for operating on 15 meters and he gave me a spool of 450Ω ladder line to play with. I was browsing on DX Engineering the other day and saw a hardware kit for building dipoles. I remembered Steve’s ladder line, and decided to order the kit in hopes of cobbling together a nice antenna for SPAR Winter Field Day coming up this Saturday.
The kit arrived Monday, along with an LDG 4:1 voltage balun for connecting the ladder line to the antenna tuner. I noticed two problems: My roll of ladder line was too wide for the dipole “T” which was apparently designed for something much narrower. Not really a big deal, but annoying.
Problem two manifested itself later when I started assembling the centerpiece and realized the included nuts were the wrong gauge and they only supplied three of them, instead of the 8 listed on the parts sheet. Rather than send the kit back to DX Engineering, I just bought the parts I needed from a local home improvement store.
I sought narrower ladder line locally, and arrived at this stuff, sold at Radio Shack of all places: 300Ω TV twin lead. Not really ladder line, but it’s low-loss balanced line and many hams seem to like it, evidenced by the numerous reviews on eHam for it. I bought a 100-foot roll, and enough 18-gauge spooled wire to make a dipole for 40 meters and on up.
Once I arrived home I set out to strip back the covering and foam insulation to get at the twin wires. I found the process much more difficult than I expected. Fortunately I have a technique now: Split the strip down the middle 2-3 inches with a very sharp knife and spread the wires apart. Carefully cut some of the plastic around the wire, but don’t cut too deeply or else you’ll cut the copper wire itself. Just score it. You can then give the scored portion a twist and the plastic will break. Pull upwards and the foam and outer plastic will slip off the copper wire. I don’t know if that’s the right way to do it, but it worked for me.
Anyway, I assembled this thing and I’m looking forward to seeing if it works at all on field day this weekend. If it fails, I still have the vertical…