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| Twin-Radial ¼ λ 70 cm Ground Plane |
Mounting screws ensure that the base plate and the BNC flange make contact with the pill box.
SWR at 435MHz is better than 1.5:1.
Related post: A ¼ λ Ground Plane for 70 cm
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Twin-Radial ¼ λ Ground Plane for 70 cm
The driven element of this antenna is a telescopic whip. It is mounted in a tubular aluminium pill box using polythene end-caps as insulators. A BNC flange-type socket is mounted on the bottom end-cap, with its centre pin soldered to the whip.
Two aluminium-strip radials are bolted on to an aluminium base plate, beneath which the driven element assembly is attached. The whip clears the base plate through a central hole.
Mounting screws ensure that the base plate and the BNC flange make contact with the pill box.
SWR at 435MHz is better than 1.5:1.
Related post: A ¼ λ Ground Plane for 70 cm
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Mounting screws ensure that the base plate and the BNC flange make contact with the pill box.
SWR at 435MHz is better than 1.5:1.
Related post: A ¼ λ Ground Plane for 70 cm
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Open-stub J-Pole for 70cm
Telescopic whips and an old terminal block insulator make this open-stub J-pole for 70cm.
The stub portion of the driven element is of 3/16" copper tubing (if only to make up for the shortage in length!).
The dimensions are: Driven Element - 495mm, Stub - 165mm and Spacing - 16.5mm.
The elements are wired to a BNC socket mounted on the block.
SWR at 435MHz is less than 1.5:1.
Related post: End-fed Sleeve Antenna for 70cm
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| 70cm open-stub J-Pole Antenna |
The dimensions are: Driven Element - 495mm, Stub - 165mm and Spacing - 16.5mm.
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| 70cm open-stub J-Pole Antenna - Schematic |
SWR at 435MHz is less than 1.5:1.
Related post: End-fed Sleeve Antenna for 70cm
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