Other Method For Field Strength Testing

Other Methods For Field Strength Testing

Calculating db gain or loss by 2 distances

If you are measuring the field strength from a transmitting antenna that is low gain, or under low power, or both, and if you want to calculate db gain; 1st move the field strength meter closer or farther until you get a 1 volt reading on the field strength meter from the reference transmitting antenna, and then measure the distance between the transmitting antenna and the field strength meter. Then change transmitting antennas, and then move the field strength meter until you get a 1 volt reading on the field strength meter from that transmitting antenna, and then measure the distance between the transmitting antenna and the field strength meter. You have the 2 measurements of distant at 1 volt of field strength measurement in order to calculate to the db (decibel) gain or loss.

Table of Definition
db =	gain or loss of voltage or power in decibels*
dbd =	gain or loss of voltage or power in decibels over a dipole antenna*
dbi =	gain or loss of voltage or power in decibels over an isotropic antenna*
D1 =	Distance of reference transmitting antenna in feet or meters @ 1 volt reading.
D2 =	Distance of a directional antenna or another antenna in feet or meters @ 1 volt reading.

*Note: negative db is loss, and positive db is gain

To calculate decibels (db) gain or loss by the 2 distances:

db = 20 x log (D2 / D1)

Notice

This webpage is subject to change without any notice in order to improve more accurate information.