Description

The SW1 Shortwave loading core allows you to easily make tuned resonance dipole antennas for greatly boosting shortwave reception. Matches the natural 75 ohms of a dipole antenna to the 50 ohms of your shortwave receiver or QRP transmitter. Isolates noise pickup. Allows your dipole , one complete length of wire to not have any break in connection at the center point where the highest current flow is at. Will match 1:1 SWR across the entire shortwave band, you simply make adjustments to your antenna length or angles. Typically SWR for low to the ground dipoles or indoor antennas will run between 1.5:1 to 1.7:1 You can adjust this to 1.0:1 by angling the antenna or using thick wire. Its a short wave antenna-experimenters dream come true. Low to the ground antennas or even antennas laying directly on the ground can be easily tuned up. Make bi-directional dipoles and experiment with beam antennas without concern of coaxial cable becoming an unwanted resonance or noise pick-up part of the antenna. This shortwave loading core gives you the ability to make electrically isolated antennas so that stray noise on the outside of your coaxial cable does not get conducted to the antenna of the receiver. The core isolates and matches the antenna to your shortwave radio for maximum reception. Simply pass 1 or 2 wire turns through the core and connect to your shortwave radio’s antenna and ground terminals via your existing 50 or 75 ohm coaxial cable. You will need cable with bare wire on one of the ends. Then pass 1 or 2 wire turns again through the core and this will be your antenna. Comes with instructions and chart of approximate length of antenna wire needed for reception in the various shortwave meter bands. You will have to experiment at peaking the band center by trimming your antenna wire down. Instructions give approximate lengths of wire needed for 2.5 , 5, 10, 15, 20, 25 MHz. Time Signal Radio Station WWV from Colorado can be received easily for initial testing. Instructions include simple formula that works using any calculator to determine approximate antenna wire length for any frequency between 1.8 MHz to 50 MHz. The antennas made with this core are approximately 1 MHz wide and offer high Q. You can build a multi band fan dipole to receive several bands with one antenna system. Experiment with isolated full-wave loop antennas also. The Shortwave Loading Core prevents RF from being received on your coaxial cable shield run. It does this by using low loss magnetic coupling inside the core. Your antennas are effectively free-space dipoles without electrical connection to your coaxial cable, allowing less noise pickup and true dipole bi-directional pickup pattern. You get: The SW1 Shortwave Loading Core and instructions for connecting which tells the approximate wire lengths (that you supply) needed for dipole antennas for various shortwave meter bands.