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VHF mounting location - mast or radar mast

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Gents - first, a note of sincere appreciation to Ben and regular contributors for the quality of research and commentary in this forum.

I have a question about VHF antenna mounting locations. I realize the best location is up high. My carbon mast is 70' above the water. But with that distance and corresponding reduction in power, plus weight of the cable(s), desire for AIS-B, a Lopolight and Airmar PB-200, is it feasible to mount the VHF antenna on a radar mast which is 10' or so above the water? My thinking here is that with less power loss and a higher quality antenna, the effective range may not be substantially different (or substantial enough to be a practical hindrence to coastal New England cruising) and the cleanliness of the installation/maintenance is a valid trade-off.


2 Replies

  • Michael, Typical values for line loss of the most commonly used coaxial cable, RG-58A/U, is approximately 9.5 dB per 100 feet. The loss of range in having the antenna lower will be more than anything you will loose as a result of a longer coax run IMO. Using a larger diameter coax, having good clean connectors and a maximum gain antenna will improve your installation. Chuck

  • Chuck, yes I agree with you. But there are other considerations for relocating this antenna and I'm wondering if in balance, it's viable. My typical max. transmission distance requirements is less than 5-7 miles, most often less (i.e. simple hailing of a launch, etc.). So gaining max distance isn't the objective.