DIY Fuchs shortwave wire antenna

Today I wrote an article on how to make a telegraph transmitter and how I made radio communication with it using a web-sdr radio receiver at a distance of 2500 kilometers. The transmitter has a power of about 1.2 W, and the distance is so great. How are such large distances covered? There are many different conditions, but one of the main ones is a good antenna. The antenna that I used for my transmitter is called a Fuchs antenna. I will tell you in detail how to make it in this article and at the end you can watch a video of how I made radio communications over long distances using such an antenna.

This antenna works well at frequencies of 3.5-12 MHz, the frequency is changed by a variable capacitor. To shift the operating frequencies, it is necessary to rewind the transformer windings. To make an antenna, you will need a wire about 45 meters long, but you can use a wire of a different length. I live on the tenth floor. The wire goes down from my balcony and is attached to a road sign in the yard through an insulator. Of these 45 meters of wire, I cut off about 5 or 7 meters, or maybe more, as unnecessary. In general, the length does not have to be very precise. If you live on the first floor, take as much wire as you need to throw up onto a tree or some support, but not less than 10 meters, or maybe more, I have not conducted tests here. The main thing is that the wire does not go above or under the power lines. Observe safety precautions. And it is desirable that the wire be inaccessible to neighbors, they can cut it. To prevent this from happening, on the balcony I made a kind of fishing rod protruding from the balcony by 1.5 meters. The neighbors below will not be able to reach the wire because of this, well, unless they try really hard. I bought the wire in a store for electricians and it is called a cable. You can buy a field wire, it is thinner and the wind load on the wire will be less. For low transmitter power, the wire diameter can be 1.5 mm

Only one wire can work well at one frequency. In order for this wire to work at different frequencies, it is necessary to make a matching device consisting of a variable capacitor with a capacity of 12-495 pF and a transformer with two windings. The transformer is wound on a plastic frame with a diameter of 20 mm. Winding L1 contains 20 turns of wire with a diameter of 0.7 mm, winding L2 - three turns of wire with a diameter of 0.7 mm. By adjusting the position of L1, you can achieve the best antenna characteristics

I checked the antenna with a radio station at different frequencies. 3.5-12 MHz, the work is quite excellent. The antenna requires a counterweight or grounding. This can be a 2-3 meter long wire dropped to the floor

Here I have secured the antenna below to the road sign in the yard. No one has made any complaints yet, but it would be better if the wire was smaller in diameter and less noticeable