A radio that runs on a VHF frequency commonly functions as a marine radio. That means you can mount its VHF antenna on a boat for broadcast signals while at sea. If you have just set up a VHF radio on your boat, there are quick ways to check the antenna and make sure it's functioning properly.
Turn on your VHF radio and make note of your frequency displayed on the radio transceiver. Give the frequency to a friend with a working VHF radio. Have the friend tune his radio to the same frequency as yours.
Check with the friend to see if she is receiving your signal. If not, you may have a problem with your antenna. For more in-depth testing, proceed to the next step.
Remove the antenna cable from your radio. Plug one end of the antenna cable into the output jack on the side of a VHF radio tester. These testers are small units with front displays that register the wattage output of a VHF antenna.
Plug the antenna cable into the input jack on the opposite side of the tester. Make sure your radio is on and the antenna wattage will display on the tester.