Three Easy DIY Antennas for Beginners

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Measurement of Antenna Impedance is influenced by the length of coax (in terms of multiples of wavelengths) between antenna and Measuring Instrument.

measuring antenna performance?

With any analyzer it is necessary to take into account the coax feeding the antenna. The actual antenna feed impedance are modified at the far end of the coax by the characteristic impedance of the coax. Usually some sort of calibration using a load/open-circuit/short-circuit at the end of the cable should be performed, and then this cable piece can be used as a calibration reference for future measurements using that particular cable. If a calibration at the far end of the coax cannot be per…

 

 

measuring antenna performance?

AN EXPERIMENT TO DEMONSTRATE HOW THE MEASURED VALUES ARE AFFECTED BY LENGTH OF COAX BETWEEN ANTENNA ANALYZER AND DEVICE UNDER TEST. MEASUREMENT OF 75 Ω DUMMY LOAD THROUGH DIFFERENT LENGTHS OF RG6 COAX TEST SETUP [image] COAX PIECE #1 Physical length =130 mm (including connectors), Electrical length = 130/0.84 = 155 mm = 0.564 λ Measured R= 44.92 ohm [image] COAX PIECE #2 Physical length =150 mm (including connectors), Electrical length = 150/0.84 = 179 mm = 0.651 λ Measured R= 34.01 …