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NI7J Projects

82 foot in height 80/160 meter four wire caged vertical.

Tower and 21 foot 2 inch DOM tubing is the support means for caged vertical.
77 radials 75' to 85' in length used.

Three tin plated #10 and one #6 copper wires held out 4 feet from east side of tower,
using 1.25 inch solid fiberglass rod. All support arms are 1.25 inch solid fiberglass.

Aluminum tubing on top of 2 inch DOM tubing is insulated by use of Delrin bushing.

The four vertical wires connect to the insulated four sections of 6061-T6 aluminum
tubing at the 72 foot level.

12' diameter 4 lb aluminum capacitance hat located on top.

Multiband dipole support arm at 72 feet fed with 450 ohm ladder line.
Dacron lifting line for dipole is seen to the right of ladder line.
Remote tuner located in upper Hoffman box at base of tower.

Antennas SWR low point is 1.1:1 at 1.850 Mhz using 3.2 uH shunt coil.
2:1 SWR bandwidth is 110 KCs, this is upper Aim-4170 plot.
Lower plot has home brew T type remote tuner in circuit.



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Click here to inlarge upper image