Loop Antenna is designed especially for working from journey.
The Antenna is ready for operation from disassembled to assembled
condition in several minutes. Antenna contains cheap or not hard
to find stuff. I spend less $ 50.0 for kit for the antenna. However,
I have managed to buy the vacuum variable capacitor (old surplus
stuff) for good price. Figure 1 shows design of the Magnetic
Loop of the antenna made of from a RG-213 Coaxial Cable
in 3- meter length. So the loop has diameter near 1- meter. At both sides of the coaxial cable there are installed
male PL- 259 connectors. The loop is formed by wooden spreaders
(in diameter 14- mm) with plastic holders on the ends. Figure 2 shows Central Spreader.
shows End Spreader. Coupling Loop has diameter 200- mm.
The loop made from copper strip in 10- mm wide. One
end of the Coupling Loop directly connected to the central core
of feeding coaxial cable (50- Ohm) another end of the Coupling
Loop is connected to the shield of feeding coaxial cable. Several
ferrite snap RF chokes (what were in my junk- box) are installed
on feeding coaxial cable near the Coupling LOOP. Figure 4
shows the Coupling Loop.
The vacuum variable capacitor was old military Russian
one, type KP, 5- KV, 5- 250- pF. The
capacitor is placed in the box that literally holds the Magnetic
Loop Antenna. Figure
5 shows the box. Figure 6 shows the box inside. Two female SO- 239 connectors
are installed at both sides of the plastic box.