Can I splice a random wire antenna?

Question

I have an Icom AH-4 with a random wire antenna. I have a fence around my property that is 60 feet long by 70 feet wide. The outdoor tuner is placed at the begining of the 60 foot section which leads to the 70 foot section. I intend to both receive and transmit. I would like to be able to tune 80 through 10 meters and have used a webpage with a chart which suggests that I use between 134-136, 140-142, 150-152 or 169-171 feet of wire to make my antenna.

1. I can only buy outdoor wire in 100 or 500 feet lengths. Can I buy 2 X 100 feet of 16 guage PTFE cable and splice them with solder in the middle? I don't really need 350 extra feet of wire.
2. Does it really matter if I make the right angle turns at the corners and go around the fence?

I do not need suggestions about other types of antennas unless they are shorter in height than 6 feet. HOA rules.

Answer 1

A spliced joint makes very little difference to an HF antenna electrically, but if you do solder it then you should protect the solder joint from the weather, because the solder will corrode faster than the wire.

Right-angle turns in the wire will affect the radiation pattern, but since the radiation pattern of a "random" length wire antenna is funny-looking anyway, you're not likely to notice the difference from a bend or two. The wire bends will probably change the antenna's impedance somewhat, but since you plan to use an antenna tuner, you probably won't notice that difference either.

You could simulate the antenna to get a more exact idea of the radiation pattern and the impedance, but if I were in your shoes I'd just try it. You might find that a particular length makes trouble for the antenna tuner on one or more bends; if so, just change the length of the antenna a bit and then try again. If you double the wire back on itself, then electrically the doubled-back part of the wire vanishes. (OK, really it couples to the wire it's laid against and radiates along with it, making a slightly thicker wire electrically, which makes no difference.) So if you have extra wire you could double the extra part back on itself, and then if you want to lengthen the antenna later then you could just straighten part of the wire out, and then you wouldn't have to splice wire again.

Answer 2

Ham radio is about experimenting, Wire antennas are relatively cheap to make. Go ahead and try it and see how well it works.

I am not sating you should not read about various antennas and ask other people's opinions. You should, but at the end of day go ahead and try it.

In my experience splicing wires should not be an issue. mechanically fasten the wire together by twisting them around each other then solder them. I would also protect the spice from the environment by wrapping with tape or maybe plastic sleeve filled with silicone.

Look up the Western Union splice, https://en.wikipedia.org/wiki/Western_Union_splice

Answer 3

Splicing the wire is just fine electrically, but if you're using multistranded cable you probably won't want to solder it. Soldering makes a stiff section which concentrates the stress at the joint, leading to premature failure.

Swaging is ideal, but if you don't have the necessary tool then rope clips are an acceptable alternative.

Answer 4

Yes, you can. If you want it to stand up physically for a long time, you should

1. Make a good, strong splice. To make a "lineman splice" you strip several inches of each wire, overlap them, and closely wrap each one around the other one, as in this diagram (A through D are the four steps of one variation; E and F are other variations with slightly wider spacing. Any of them are fine).

2. Solder thoroughly and evenly. You want solder to flow throughout the splice, not just cover up the outside. This needs consistent heating.

3. Protect it from the elements. Use heat-shrink tubing, or self-amalgamating tape wrapped over with vinyl tape, and cover at least an inch of insulation on either side to avoid water creeping in.

If you're just throwing it over a tree for a summer, feel free to ignore all of this and do whatever.