Full Sized Dipole

Full Sized Dipole

This page describes the performance of a full sized 20 metre halfwave dipole. It is  fabricated using telescoping tubing so that it can be mounted on top of a sturdy fibreglass mast up to 7 metres high. This allows the dipole to be rotated to the direction of interest for broadside radiation. This antenna is about as big as practical for a portable antenna but can be shortened considerably with aid of low loss loading coils. The merits of this antenna are its high gain and ease of matching. The disadvantages are its relatively large size.  However, it makes a good antenna for field day operation.    Gain @ 14 MHz = 5.1 dbi at a take off angle of 30 degrees. Dimension are given in the 4nec2 file.
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Polar Pattern..Vertical plane Azimuth angle = 30 degrees
Antenna Layout Oriented along the X axis Azimuth = 90 degrees
Horizontal Gain All radiation is broadside
Vertical Gain Small radiation off the end (endfire)
Total Gain Radiation is broadside
Frequency Response VSWR = 1.6 @ 14 MHz SWR varies with height. The loaded dipole give a better match due to smaller radiation resistance.
Dipole Mount for Al tubing antenna.  Very strong but heavy. OK for 14 MHz but very good for 18 MHz and above. The gray tube covers a ferrite 6 element choke.