VHF antennas, when to replace?

[Kiltmadoc]

So, I was at my local west marine the other day and they had an antenna on clearance for $10 (Shakespeare 5247 model). I have already replaced my VHF cable, so now I wonder if I should replace my antenna as well. But, how would I know if the old antenna is bad?

Is there a way I can use a multimeter to test it?

Or do I have to wait until the mast is on the boat in order to know if the antenna is good or bad by powering up the radio?

For $10, i did buy the antenna, but then I began to wonder if I was wasting $10.

[BubbleheadMd]

A VSWR meter can help you determine if an antenna or the cable is bad. This meter measures "reflected power", or power that is being reflected back at your radio, instead of being radiated out of the antenna element.

In theory, you should have a 1:0 ratio- One wave out, zero waves reflected. You'll never get a reading that good, but you can get close.

You know, for $10 bucks I'd just buy the damned thing and keep it around as an emergency spare. Or install the new antenna and keep the old as a spare.

[btrayfors]

Marine VHF antennas almost never go bad, unless they are physically damaged or water is allowed to intrude into the loading coil.

The $10 for a 5247 is a steal (usual price $50 or more), but it's a "lift and lay" foldable antenna. This is not usually one which you'd put atop your mast, unless perhaps you trailer the boat and a folding VHF antenna would be useful.

I'd stick with what you've got, and keep the new one as a spare. Or, if you're feeling frisky, install the new one on the sternrail where it can serve as an emergency antenna or one to connect your handheld VHF to for greater range :-)

Bill

[olson34]

Since most sailors will replace their standing rig on a scheduled basis -- about 15 years max -- that is often done with the spar down. Good time to replace the antenna, coax, and any old untinned wiring in the spar. Lights will usually be at or beyond their lifespan also.
We did this all at about 15 years and the base coil on the orig. antenna was compromised with water and the seal was UV-damaged. Coax ages and needs replacement. The old anchor, steaming, and foredeck lights were shot due to UV.

Just look at this stuff as part of your Preventative Maintenance chores.

Houses, cars, boats, planes, whatever... Alas, they all obey the law of Entropy.


O-my

[mdbee]

Check out Metz with a lifetime warranty. I sent my old antenna in and they check it out for free. They sent me a new one, no charge.

It was over 15 years old and came with my boat. They said it didn't matter that I wasn't the original buyer. (The plastic/vinyl(?) covering on top had cracked.)

I believe the USCG also uses the same model.

I haven't used a Shakespeare antenna however I did buy one of their spliters to connect to my FM radio. I noticed I was having an issue with my VHF radio. After quite of bit of searching, I discovered that the spliter had a short and causing the issue. Actually it was a cable that had come with the spliter from Shakespeare. The center terminal crimp was broken allowing things to move around and short. I ditched the spliter, finding it really wasn't needed with our reception here.

Not a fancy website but good people:
Metz Communication Home Page