Out on the open water, a boat’s VHF marine radio can be an important lifeline to summon assistance from the authorities or other boaters in an emergency. Should you ever need to make an emergency marine VHF radio antenna for your vessel, here is how to do it.

No vessel’s VHF radio will work properly without an antenna attached. A sailboat’s VHF marine radio antenna is often located on top of the mast, and if the vessel is dismasted, the radio system will be lost. Antennas may also be located on a stern rail, and may become damaged due to collision or from taking on a large wave. Also, an  antenna may become damaged due to corrosion or other factors, and not be usable in an emergency. For those who venture into coastal waters, calling “Mayday” on VHF channel 16 is often the best way to summon help from the Coast Guard. Here is how to quickly make an emergency VHF marine radio antenna for your boat.

Step One In Making An Emergency Marine VHF Radio Antenna:

Locate your radio’s coaxial antenna cable at the back of the unit. This may be a round white or black wire, connected to the radio with a connector similar to the one below.

Follow the antenna cable and try to find somewhere that you can safely cut it, as close to the malfunctioning antenna as you can. You should try and get a length of coax at least ten feet long or longer. Next, pull the VHF antenna coax out from where it has been routed and throw it up on deck.

Step Two In Making An Emergency VHF Radio Antenna For Your Boat

Now go up and straighten about two feet of the end of the coax out on the deck of your boat. Now take a utility knife and cut the outer plastic covering along 17 1/2″ of the cable. Once you are done, pull the outer plastic covering off the coax to expose the braided wire shielding. Next, at a length of 17 1/2″, double up the wire as shown below and rough apart the wire braid until you see the next layer. Depending on what type of marine VHF radio coax cable you have, you may either see a clear outer covering or one covered in aluminum foil, like the coax in the next photo. Pull the inner part of the cable out of the braided cover until it looks like the the second photo below.

Step 3 In Making An Emergency  Antenna For Your VHF Marine Radio

Now that you have separated the two main parts of the coaxial cable you will need to remove any outer shielding material from the center conductor. If your coaxial cable is clear, you don’t have to do anything, just skip to the next step. Carefully, without cutting the delicate copper center conductor, cut off any aluminum shielding from the wire so that all you have is either plastic or bare copper wire. You should have 17 1/2 inches of wire on one side, and 17 1/2 inches of outer shield on the other side, as seen below.

Step 4 Of Improvising An Emergency Boat VHF Antenna

Separate the two equal pieces of wire and pull them in opposite directions of each other. You now have a marine VHF radio dipole antenna. Antennas work best if placed as high on your boat as possible. There are a couple of ways to rig the dipole antenna you have made. You can take fishing line and stretch out each end and tie them to a part of the boat, or you can take a piece of non-conducting material, such as the fiberglass fishing rod seen in the photo below and tape the emergency marine VHF radio antenna to it.

That’s it. Now all you have to do is place the antenna up at the highest feasible point on your boat, away from other objects.  It takes about ten minutes to make this emergency VHF marine radio antenna. This emergency marine radio antenna is not for long term use. Damage to your radio could result from using an improvised antenna that has not been tuned to your set using an SWR meter.