At the end of a long wire, the impedance is usual high. With a 49:1 transformer, the SWR is usually well within range of auto-tuners found in most modern rigs. This usually means that a multi-band antenna can be erected covering most or all HF bands. In many cases, the SWR is sufficiently low that no tuner is needed at all.
For those unable or simply preferring not to make one, commercial antennas or baluns are available. One that was available was the X80. I bought mine many years ago. It worked well, but was only up for a few weeks as most of my operating was on a single band - 10m. I swapped mine for an active RX antenna.
I think modern versions can come in fibre glass, but are more expensive.
If you are happy to make your own, all that is needed is the balun in a suitable waterproof enclosure with connectors and a long wire. I think the wire is ideally not a multiple of half waves. There are several designs on the internet I believe. If you are happy to experiment, you can try different wire lengths. The X80, and its successors, looks like a CB vertical. Often people put things inside aluminium ones to make them bend less in high winds. I never did this.
See https://sites.google.com/view/g3xbm4/home/antennas/x80 .
1 comment:
I did build an antenna like this many years ago. If propagation is right it definitely works. However a better alternative is using an autotuner at the feedpoint and use a 1:1 balun or 1:4 balun instead, or no balun at all depending on the tuner range. In the past I also used verticals fed by open line, they work very well and there is no loss in coax cable. 73, Bas
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