This page gathers a lot of formulas to calculate waveguide wavelength, cutoff wavelength and attenuation. These formulas are only applicable for dominant mode.
An output circuit of a helix traveling wave tube was modeled in High Frequency Structure Simulation (HFSS) 3D software. A design change was attempted to make the circuit have a better VSWR than 1.5:1 in the frequency range of 12-18GHz.
Do you find it difficult to measure height of your antenna tower? No you do not have to climb along it with a measurement tape, Just build this low cost jig and measure height in 15 minutes.
Anything that conducts electricity is an antenna, (usually a wire, but it could be your body) but the basic unit from which we build antennas is a wire, 1/2 wave length long having a connection in the middle to equipment. Called a dipole, it is an efficient radiator of alternating current electrical energy and is a standard of reference for other antennas.
It doesn't take very much wire to pick up an adequate signal for anything but the crudest shortwave receiver.
How to convert a standard book-size battery-powered shortwave receivers to directional reception to reduce interference. Easy construction - can be home-built.
There is significant impedance mismatch between most shortwave antennas and the receiver. With this antenna matching device you will get maximum signal to the receiver at most frequencies.
What causes fading of shortwave signals and what you can do to improve the situation.