Here are some
simple antenna calculators
Simple Dipole
Calculator
A useful and fundamental measurement in radio
antenna work is the "half wavelength". We must know how to calculate it.
It gives the desired physical length of an antenna for any operating
frequency.
The half-wave dipole is one of
the most important and commonly used antennas and is very simple to construct.
The length of a dipole is the main determining factor for the operating frequency.
For the dipole legs use an
insulated copper wire of 14 gauge or heavier. Remember to make the legs
slightly longer than the calculated length to allow for wrapping around
the end insulators.
Use 50 ohm cable such as RG58, RG8X, RG8, RG213, or 75 ohm cable such as
RG11, RG59, RG6 or 75 ohm twin ladder line to feed the centre of the dipole.
Be sure to solder the feed cable to each leg of the dipole for good electrical contact because the
centre of the dipole is a high-current low-voltage point.
It is also a good idea to provide some strain relief which can be a simple
matter of
wrapping the feed cable once around the centre insulator and securing it with
a tie-wrap.
Simple Vertical Calculator
3 element beam Calculator
Simple J Pole Calculator
With thanks to James E. Stewart Jr. - N3DNO for the beam and vertical
calculator javascript
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