Keep using my Par EF-20/EF 40
Don’t know this one, but the following works best on 20m, with less efficiency on 40m and with some additional lobes on 10m:
I bought this one (or similar) and created a similar low weight version that I always carry with me as backup antenna, additionally with one link for the 17m band.
- 49:1 with 66’ wire (no tuner)
When using a 49:1 (better for higher bands) or 64:1 (better for lower bands) coupler, you have to cut the wire for resonance to lamda/2 minus velocity factor and end effect, e.g. about 20m long for the 40m band. An antenna analyzer is really helpful.
The antenna works also on multiple harmonics, not exactly, but good enough, albeit with additional lobes.
For the upcoming Challenge, I tried a super simple vertical EFHW antenna for 10m that worked just great: about 4.5m wire hanging down from a 6m tall glass fiber pole, fed by a 49:1 coupler and some meter of coax.
- 9:1 with 60’ wire and counterpoise (with tuner)
I have no personal experience with this one, but it seems to work for many activators that use a tuner.
The length of the radiator might be a bit to long (should not get close to lambda/2 on any band) and the number, length and setup (on ground or elevated) of the counterpoises need to be taken into account.
I’m writing a document about a 20m long resonant 7-band EFHW antenna using only one switchable coil to change between two band segments.
Once the document is backed with enough data, I will post the corresponding link here.
Building antennas is so much fun, and I like to analyze them nearly every time I do an activation.