Rope Antennas
Technical Details
Installation Procedure
Antenna Lengths
Grounding Plate
Older Information
How to order


The counterpoise  for the tuner and antenna is a twin ladder 450 ohm ladder line.

On one side of the vessel either port or starboard, cut the ladder line at approximately 42-47 feet. This counterpoise has good RF resistance for frequencies in the low marine bands, which also support the amateur bands.

On the opposite side of the vessel, again below the water line, the same 450 ohm ladder line material, is cut to 32 feet from the start of the autotuner. This line gives a good RF resistance and reactance to the auto tuner for the bands below 12 MHz.

It is best to have the lines on the port and starboard side separated by at least 4-6 feet.

This 450 ladder line should be any length from 32 to 27 feet for the one side of the ladder line and the second side of the ladder line is cut to 17 feet. This side supports the higher frequencies, from above 12 MHz.

In between the radio and the grounding plate you should install a DC Block, which is simply a couple of one-way diodes to stop any DC voltage looping around in the system. This dramatically reduces noise in your radio system.

This DC Block specifically designed for marine frequencies is available on the How to order page.


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Last Modified : 09/21/09 03:48 PM