I created and built a new type of antenna during the 1980s for a /P radio trip to the Scottish island of Iona. the principle is very simple but I had never seen or heard of this configuration before I came up with the idea. My thought process was:
Start with a 10m wire dipole with a 'banana' plug/socket soldered to each end;
Using simple insulators, extend each leg with wire 'extensions' that have banana plugs/sockets on both ends;
Continue until you have all bands you want to use available.
By plugging and unplugging banana plugs it is now possible to quickly create a half wave dipole for any band you need. This antenna can be readily raised and lowered in a few minutes to effect a band change. No compromises, no tricky tuning required and guaranteed good performance on all bands that resonant half wave dipoles provide.
Only use solid metal (plated brass) connectors...NEVER anything else. The low cost flimsy ones corrode in weeks.
Cut 2 lengths of each the following sizes:
Band length(m)
10 2.4
12 0.48
15 0.65
17 0.72
20 1.29
30 2.19
40 2.95
80 10.14
These lengths are the actual cut wire lengths and include an allowance to let you tie a fixing knot (I use a reef knot) to the insulators (I use quarter inch lengths of 50mm diameter plastic water pipe). These are lengths for a CW optimised antenna but should take you to within auto-atu tuning range of any part of all bands with the exception of 80m. For 80m SSB you might need to reduce the 10.14m down to around 10m.
In recent builds I've eliminated the WARC band links because I realised that you can get 12/17/30 OCFDs that work fairly well by doing this:
12 - open 10 on one leg and 15 on the other;
17 - open 15 on one leg and 20 on the other;
30 - open 20 on one leg and 40 on the other.
You reduce the number of connectors and insulators needed using this trick.