Previously considered for shortwave antenna in which as of extension elements used inductors and capacitors (w3dzz), on this page on your blog suggest considering another shortwave antenna published in the Soviet journal Radio hobbyist and part-time engineer I.Adamkovskim (UA3APM) of Moscow region, the article came out in 1969.
The figure shows that the total antenna length of about 40 meters, shortwave antenna operates in the 80,40,20,14,10 meters . Input impedance of 600 ohms , depth of about 20 meters from the surface . As the supply line used ribbon cable 300 ohm. This cable is made of transformer converts the input impedance of the short-wave antenna (600 ohm) to 300 ohms resistance . Why do I need this! ? All banal just - in those years in the USSR was not ready supply line impedance 600 ohms , but there were 300 ohms. If you decide to make this dish one to one , then overcame drawing in which all dimensions are in meters and millimeters. Coil wound carcass without winding diameter of 30 millimeters , 43 millimeters winding length . These wire coils - Copper 1.2 millimeter its diameter . ( Having instrumentation I think will be easy to set up ) . Capacitors used in this shortwave antenna pifarad have a value of 300 with a working voltage of at least 1 kV . After setting up the short- circuit antenna to be sealed .
ps: capacitors and coils in the shortwave antenna play the role of automatic switches.
The figure shows that the total antenna length of about 40 meters, shortwave antenna operates in the 80,40,20,14,10 meters . Input impedance of 600 ohms , depth of about 20 meters from the surface . As the supply line used ribbon cable 300 ohm. This cable is made of transformer converts the input impedance of the short-wave antenna (600 ohm) to 300 ohms resistance . Why do I need this! ? All banal just - in those years in the USSR was not ready supply line impedance 600 ohms , but there were 300 ohms. If you decide to make this dish one to one , then overcame drawing in which all dimensions are in meters and millimeters. Coil wound carcass without winding diameter of 30 millimeters , 43 millimeters winding length . These wire coils - Copper 1.2 millimeter its diameter . ( Having instrumentation I think will be easy to set up ) . Capacitors used in this shortwave antenna pifarad have a value of 300 with a working voltage of at least 1 kV . After setting up the short- circuit antenna to be sealed .
ps: capacitors and coils in the shortwave antenna play the role of automatic switches.
