VHF Radio range

A

Arnold

Member
Joined
Oct 14, 2003
RO Number
12330
Messages
544
How far off the coast can I go before losing VHF capability?
 
VHF radio is "line of sight", which means that as long as one antenna can "see" the other one, they can communicate. Therefore, VHF range depends on antenna height. If you are trying to communicate with a tall antenna, you can be much farther away.

For example, around here, the CG has tall antennae, I can hear them talking to boats 50 miles away, but I can't hear the boat's talking to them.

Rmember, that mountains and buildings limit range, as well.
 
Concerning handheld VHF radios, what's a realistic range used on a small boat?

(I just purchased one as a B/U)
 
I've gotten over 5 miles with my handheld, across water.
 
The question is hinged on the quality and height of your antenna. A USCG helicopter, transmitting 2 watts will cover a large area due to the height of the antenna. Your standard radio with a typical 8' antenna mounted 4' off the water will easily reach 13 miles. After that, you'll hear interference.

The very best way to improve signal, is to mount a short sailboat antenna as high off the water as you can get it. Have no breaks in the coaxial cable. Put a gold connector on the coax where it connects to the radio.
 
On my first boat, I used a 3dB antenna mounted to the frame of my delta canvas and attached to my handheld antenna. It worked very well. I had about a 25 range under the best circumstances.
 
Mitch,

One of the best things you can do to improve the range of a handheld for emergency usage is to purchase a connector to go between it and your fixed mount antennae. You will still only have 5W of power but a much higher and better way of transmitting it.
 
quote:
Originally posted by Arnold

Click to expand...
Here is the formula to determine range:
Calculation for Range of an Antenna:
6db Antennas: Square Root of Height (in feet) above water x 1.15= Range in miles
9db Antennas: Square Root of Height (in feet) above water x 1.52= Range in miles
Remember to perform the calculation for BOTH vessels, then add the results for the range between two vessels.
 
quote:
Originally posted by bigwaveohs

quote:
Originally posted by Arnold

Click to expand...
Here is the formula to determine range:
Calculation for Range of an Antenna:
6db Antennas: Square Root of Height (in feet) above water x 1.15= Range in miles
9db Antennas: Square Root of Height (in feet) above water x 1.52= Range in miles
Remember to perform the calculation for BOTH vessels, then add the results for the range between two vessels.

Click to expand...


This makes so much sense, easy to remember and easy to calculate!

Arnold, in looking at your original question, the answer is simple, you will never lose VHF capability, until the batteries die.
 
Hogan is known for being a smarty pants, but he's not a bad a guy most of the time!
 
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