In article ,
Vinnie S. wrote:

A 130 ft. dipole fed with 450 ohm ladder-line through a good
choke is hard to beat as an all-HF-band antenna and costs
about $25.

I have to do a inverted V config. I would be unable to run it horizontal. Can I
build one using simply a coax feed?

A single dipole, fed with coax, configured as an inverted V, will
serve well on its resonant frequency and is also usable on its odd
harmonics. For example, a dipole cut for 40 meters (nominally 66 feet
in length for a horizontal, and perhaps 60 feet in length as an
inverted V) can usually be used on 15 meters as well since that's
close to the third harmonic.

Such an antenna will not serve well as an "all-band" antenna. Its
feedpoint impedance will be too high, or too reactive, on non-resonant
bands (e.g. on 20, the above dipole will have a very high feedpoint
impedance). You may be able to tune it on non-resonant bands using a
wide-range external transmatch, but the losses in the coax and
transmatch due to the high VSWR will likely be prohibitive.

Several solutions to this:

- Feed the dipole with ladder line or open-wire line, use a good choke
or balun and a good tuner/transmatch, and if necessary tune the
length of the wire so that the impedance seen at the transmatch is
acceptable.

- Build a multi-wire "fan" dipole, with one set of wires cut for each
band of interest. These are somewhat easier to trim (less
interaction between the wires) if the wires are fanned apart at a
broad angle, but it's quite possible to get them to work with each
wire simply hanging 6" below the next-longest one using simple
insulators of some sort. I use a three-wire fan dipole of this
sort, cut for 40/20/10, fed with coax, and it works quite respectably.

- Use a trap dipole (feeding with coax should be fine).

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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