Hi all. Looking to see if the Shakespeare 5101 Marine VHF antenna can be used effectively in a base station at home? Thanks in advance for the guidance.
Can a VHF Marine Antenna be Used on Land?
- Thread starter thinbluebbq
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Yes, no problem.
mmckenna
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Just remember to periodically splash some salt water on it so it doesn't dry out.
But seriously…. Those are usually 1/2 wave VHF antenna, and have some useable bandwidth. Should work just fine for 150-170MHz.
But seriously…. Those are usually 1/2 wave VHF antenna, and have some useable bandwidth. Should work just fine for 150-170MHz.
For reception yes, if you want to transmit within the marine band from home you would need a shore station license.
wowologist
Certifiable
And most marine antennas that are made to mount over water don't have physical ground plane elements and are using the water as a giant ground plane, so you may actually need to create a ground plane for it.
Does home mean in the house or at the property? Lol Last year I regularly did radio checks from my boat while it was on the trailer using my marine radio before heading out. I was surprised at the range considering I was 17 miles from the water in densely populated area with lots of trees.
While maintaining radios for a fleet of vessels on the west coast, it was common to see the same antennas commonly mounted to vessels used at ports and marina's for shore stations. These were mostly Shakespeare fiberglass antennas. If they are not good enough for marine grade outdoor antennas, I think their factory seconds become fishing rods......joking. Then there are those that stream the feed to Automatic Identification System (AIS) use to track vessels, which seem to go high dollar and buy Morad fishing boat antennas and use them on land. They work, but beware the legal side as some have noted. They are still 25/1 watt radios in VHF, so you will get decent range, even in the evergreen forests of the West coast.
Not really. All marine antennas I know of are self sufficient and ground independent. If anything, a closer proximity to flat earth or seawater as in below a few wavelengths above ground will push the radiation pattern upwards and loose gain at the horizon. All vertical antennas regardless of ground plane or ground independent and at any frequency will act the same.
wowologist
Certifiable
"
Not really. All marine antennas I know of are self sufficient and ground independent. If anything, a closer proximity to flat earth or seawater as in below a few wavelengths above ground will push the radiation pattern upwards and loose gain at the horizon. All vertical antennas regardless of ground plane or ground independent and at any frequency will act the same.
Since this antenna has one element straight up from the connection at the base, and is "usually" 1/2 wl ....where do you think the other pole of the di-pole is?
Not really. All marine antennas I know of are self sufficient and ground independent. If anything, a closer proximity to flat earth or seawater as in below a few wavelengths above ground will push the radiation pattern upwards and loose gain at the horizon. All vertical antennas regardless of ground plane or ground independent and at any frequency will act the same.
Since this antenna has one element straight up from the connection at the base, and is "usually" 1/2 wl ....where do you think the other pole of the di-pole is?
mmckenna
I ♥ Ø
Often the cheap marine VHF antennas are just stripped back coaxial cable. The other pole is the outer braid pulled back over the coax, or dangling down inside the tube. The shorter sail boat antennas that they run at the top of the mast is 1/2 wave and uses the coax shield on the feedline. Again, no ground plane.
Better fiberglass antennas use actual metal elements.
Keep in mind that most recreational boats are fiberglass, so no ground plane under the antenna.
mmckenna
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Great info on Shakespeare antennas.
That strip of foam does not help there either, as many times the top cap falls off, breaks off, and then water get inside the fiberglass rod, corroding the entire length of wire "antenna" until it fails. Had an entire batch of Shakespeare antennas do this on a small fleet of ships in Puget Sound a few years ago. I switched to Morad antennas at that point.
If its a dipole element then it has everything it needs and no ground required. Many smaller VHF marine sticks are the equivalent of a J-pole with a matching circuit at the base of a 1/2 wavelength element. Its self sufficient and no ground or ground plane required. Some larger versions are stacked elements, 1/2 or 5/8 wavelength with 1/4 wave phase inverting stubs between elements and a bazooka balun or equivalent in the base so no ground plane is required.
A ground plane for an antenna must be right at the feedpoint to be considered a ground plane or counterpoise. I have never seen a marine antenna mounted so its base is touching the water to make use of it as a ground plane.
A ground plane for an antenna must be right at the feedpoint to be considered a ground plane or counterpoise. I have never seen a marine antenna mounted so its base is touching the water to make use of it as a ground plane.
And I'll add to this just because I like to stir sh*t up. In general, with equivalent radios and antennas at each end, you will probably get less range or varying range across sea water on VHF/UHF compared to flat earth due to the better conductivity and reflection of sea water vs dirt. The problem arises from ground bounce, or water bounce where the direct path signal is interfered with by the signal bounced at an angle off the ground or water and when the phase of the reflected signal is near 180deg out of phase with the direct signal you get signal cancelation and degraded reception. Ground bounce happens over earth or water but sea water would be a worse scenario.
With a typical land based antenna on a roof you have much less of a ground bounce problem because the ground is broken up by houses, buildings, trees, etc, leaving mostly the direct path.
With a typical land based antenna on a roof you have much less of a ground bounce problem because the ground is broken up by houses, buildings, trees, etc, leaving mostly the direct path.
hurricane2020
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Hi All newbe here I have a similar question, I purchased a marine antenna and mounted it on a pole on the chimney, its dead compared to the previous cheap one I had up, my question is do I mount the antenna on a metal bracket to the pole or do I mount it with a plastic bracket on the pole I was curious if the metal bracket on the pole is the cause of the problem. Thanks in advance
mmckenna
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As long as the antenna and the pole are not running parallel for more than a foot or so, it's not going to have an impact.
If it's "dead" compared to the other one, double check all your connections.
hurricane2020
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The pole is 8ft long vertical mounted on the chimney and the silver metal bracket with the antenna is attached to the pole, how does that sound to you I also have a plastic mount so not sure which is best I thought the pole might be the problem
To take things a step further--and maybe I'm over-analyzing--if the antenna's designed for installation on a fiberglass boat (i.e. limited ground plane) versus a steel hull--what additional considerations might be needed for optimum operation on land?
hurricane2020
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This is the antenna
SIRIO RATCHET BASE AERIAL 1.5M - Long Communications
longcom.ie
SIRIO RATCHET BASE AERIAL 1.5M - Long Communications
SIRIO RATCHET BASE AERIAL 1.5M - Long Communications
<p> – Marine antenna, Mono-band<br /> – Omnidirectional<br /> – Designed to work without Ground Plane<br /> – Protection from static discharges DC-Ground<br /> – Chrome-plated brass ferrule<br /> – Stainless steel hardware<br /> – High quality whip made of brass and copper protected by...
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