How to get better range out of Handheld VHF

[zz4gta]

Wanted to get a little more range out of my radio without having to upgrade the unit. What kind of antenna can I add to the mast that will help the signal? Right now it has close to 2 miles. But I heard adding an antenna would double that.

[sailingdog]

It would really help if you said what handheld VHF you had. Some do not have removable antennas and as such can't really do much about their range. Others have a removable antenna and can be used with an external antenna fairly easily. If you use it with an external antenna mounted fairly high up, your range will increase.

[Gary1]

There is some simple physics and a little black magic in the range of a radio in the VHF band.

The basic physics says that VHF, because of it's propagation properties is 'line of sight'. That means that it can't transmit any further than you can see.

Now, then, that being said, there is also something called 'thermal ducting', which can extend the range of a VHF/UHF signal. On very rare occasions to hundreds of miles. I haven't ever seen it happen in the marine band, but I have seen it happen on my 2 meter (144-148Mhz) ham radio.

Will a better antenna help? Yes. The 'rubber duck' antennas on most hand held radios are generally not that efficient. They're basically a small coil wrapped up in rubber. The shortest antenna that should nominally work for your VHF is about 17 inches long. That's roughly a 1/4 wavelength.

Take a look at the antenna on your radio. If it has a 1/4 turn to unlock antenna, it's probably a BNC connector, and you can put another, better antenna, mounted higher on the boat. If the antenna screws on, it MIGHT be a TNC connector, and the same thing applies. If the antenna doesn't come off easily, you're stuck with what you have.

The other thing to keep in mind is that your radio signal propagates from the tip of the antenna in sort of a donut shape. The closer to vertical you can hold the radio when you're transmitting, the better it will work. Being cool and holding it upside down at an angle will effective transmit most of your signal right into the dirt (or water).

There's more black magic in antennas, but I won't get into that here. Suffice it to say that most sailboats should restrict their choice of antennas with a gain of 3dB. Using a 6 or 9dB antenna on a boat that heels like a sailboat is not necessarily a good thing.

[sailingdog]

Be aware that some VHF radios don't use either BNC or TNC but use a smaller, more delicate SMA-type connector. If you want to connect this type to a regular VHF antenna, you'll need a pigtail adapter.

[chucklesR]

You could get a connector cable cobbled up and stick an antenna at the top of your mast - likely cost you 100 bucks in cables and such and be of dubious quality based on the quality of the connection, corrosion and other factors. IF you go that route get a real antenna to replace the 1/4 wave rubber stick on the hand held. Radio Shack is your friend when it comes to how to on that.

Best bet if you want true range better than 5 miles is getting a mounted VHF for 100 bucks, small motorcycle battery for 30 bucks and solar trickle charger for 15 more. Handhelds are great for when shouting is to hard, but just not a practical replacement for a real radio.

[Boasun]

If you can't get those connectors then you could climb to the top of the mast for a tad bit more range.
But getting a mast mounted VHF Antenna tuned to the VHF Radio that you are going to use is the best method.

[SEMIJim]

zz4gta,

Check VHF Antenna Location for more than you ever wanted to know about the subject .

Jim

[Iflyka200s]

I started that one!

(I went with a transom mount btw)