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Does VHF need external antenna?

10787 Views 30 Replies 22 Participants Last post by  hellosailor
I have inherited an old West Marine Zephyer VHF radio from a friend who upgraded on his Cal-27.

He has a mast antenna. I have none on my bare bones Edel 665. I don't even have a battery yet so this "freebie" is going to cost me at least that plus $90 for my VHF license...$200 approx total.

I have read that operating a VHF without the external antenna can damage the VHF. If I have to get some sort of external antenna I may just stay VHF-less. We are never out of reach of cell phone reception where we sail.

Do I need an antenna or not?

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Just to clarify, you CANNOT use a magnetic-mount antenna without a large metal surface to mount it on. For a marine VHF that would be something like a magnetic (so it sticks on) metal sheet about one meter square or in diameter. Not very practical unless you've got an air conditioner or oven at the top of the mast.

If you want reliable communications, permanently installing a mast-mounted antenna (with a loading coil in its base) is the way to go. If the investment (good cable & fittings cost money too) overall is not immediately justified, then even using an "emergency" antenna or a home-made one beats nothing at all.

Inland, in sheltered waters? That's still way better than nothing.

Note that from Canadian web sources, it seems legal to install the radio on the boat, and even to receive with it (monitor the distress channel, the weather, etc.) without any license, so the money doesn't all have to go up front. Traditionally radios had a removable microphone cable, so the microphone could be "secured" elsewhere, ensuring the radio was not being used as a transmitter.
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"p.s. The antenna will generally work better if it is sticking straight up. "
Well, a change from vertical to horizontal, when the other antennas (on other stations) are vertical, will reduce your signal strength by 20db. So starting with a 25W radio, once you reduce the signal by 6db you are now just equal to a 6W handheld VHF. Reduce it by 20db, and you're going to be heard as well as a handheld on the lowest power setting.

Might as well buy the handheld if you're going to do that.

Similarly, using an antenna with no radials, no counterpoise, no loading coil? Is going to be throwing out any advantage the base radio had to begin with.

As Arthur Clarke said, any sufficiently advanced technology will be indistinguishable from magic.

Yes, there is "magic" in antennas and radios.
I know 20db seems huge, but unless I'm really losing it, I remember seeing 20db quoted in a QST (ARRL) article on VHF comms, specifically 2m comms, which are so close to our marine VHF. The number kinda shocked me into remembering it. Maybe the article, or my head, was in error.
Maybe we can get some government grants to study that as a safety issue.(G)
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