# Antenna Theory

 Electronics Infoline Web

# Waveguide Properties

This page gathers a lot of formulas to calculate waveguide wavelength, cutoff wavelength and attenuation. These formulas are only applicable for dominant mode.

http://df2ck.de/tech/wg/

# RF Output Window Design for HELIX Travelling Wave Tube

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.

http://www.engr.sjsu.edu/rkwok/projects/Report.OutputWindowModel.gurvinder.ankush.pdf

# Easy antenna height measurement

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.

http://www.webx.dk/oz2cpu/ant-height.htm

# Fundamentals of Dipole Antennas

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.

http://www.kyes.com/antenna/dipole.html

# The perfect feedline for wire antennas

It doesn't take very much wire to pick up an adequate signal for anything but the crudest shortwave receiver.

http://www.hard-core-dx.com/nordicdx/antenna/feed/feed1.html

# Antenna for reducing skywave interference

How to convert a standard book-size battery-powered shortwave receivers to directional reception to reduce interference. Easy construction - can be home-built.

http://www.hard-core-dx.com/nordicdx/antenna/special/reducin1.html

# Antenna matching to Improve Sony 2010

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.

http://www.hard-core-dx.com/nordicdx/antenna/special/2010ant.html

# How to fix electrical fence noise

What causes fading of shortwave signals and what you can do to improve the situation.

http://www.hard-core-dx.com/nordicdx/antenna/special/fencenoise.html