[Elecraft] 40-80m choices antenna for KX3

[Jim Brown]

On 11/2/2022 5:38 PM, Karl W Hubbard via Elecraft wrote:
> How to rig and which antennas for my KX3 (has ATU) given the following  layout andlimitations:

When I moved into a new QTH 16 years ago, I made a scaled drawing that 
included my house, shack in detached garage-apartment, and available 
supports (in my case, tall redwoods), and in relationship to North. That 
took a while.

Antennas have two important functions -- transmit, and receive, and 
every antenna has some sort of directivity. Many antennas transmit well 
enough, but pick up so much noise from our neighborhood that we can't 
hear most of the stations calling us, and if we can't hear 'em, we can't 
work 'em!

The most noise resistant antennas are horizontal dipoles that are 
resonant on the bands where we want to use them, are fed with coax, and 
have an effective common mode choke at the feedpoint. SO -- study your 
own possible skyhooks (trees, buildings, a guyed mast you might add to a 
building) and figure out which combinations might support dipoles. 
Dipoles are VERY easy to build -- you need plain ordinary wire (I mostly 
use single-conductor house wire), a center insulator, end insulators, 
and rope to rig it.

OCF dipoles transmit OK, but they are terrible for receive noise, and 
there's no good way to kill that noise. Ditto for end-fed wires. We're 
moving into a solar maxima, so the higher bands (40-10M) are going to be 
much better than the lower ones (160-60M).

It's also possible to build multi-wire fan dipoles that cover multiple 
bands. Take a look at what I did in Chicago with a fan for 20-15-10. 
Here in California, I've used 2-wire fans for 80 and 40.

http://k9yc.com/LimitedSpaceAntennas.pdf

And it's possible to build 2-band dipoles using loading coils, and 
3-band dipoles using traps. Both types are shorter than a simple 
half-wave dipole for the lowest frequency. In Chicago, I had an 80/40 
with a loading coil that was about 100 ft long, that fit between a TV 
mast on the front of my house and another on the garage at the back of 
my lot, and it worked pretty well in some directions on 30 and 17M. 
HyPower Antenna Company (a Pennsylvania ham in his basement, advertising 
in QST) sold it.

73, Jim K9YC