VHF Antenna Replacement

[salishmermaid]

I need to replace my mast mounted VHF Antenna. The original antenna is a Metz Manta 6, but I wanted to consider other options.

I found a few on amazon:

1. Metz Manta 6 $34.25
2. Shakespeare 5215 $49.99
3. TRAM 1600-HC $29.99

Does anyone have experience with any of these or have another suggestion? Why would you pick any one over the other?

 

[Ken Cross]

Without first-hand knowledge of each model, it would be a difficult choice. I don't think I'd order an antenna online if I could avoid it. I'd want to have a look myself. Does it look like it will last? Is it mechanically strong and will it fit your mount?

After installation be sure to check VSWR to ensure all is well.

Ken

 

[jssailem]

Ken Cross
"After installation be sure to check VSWR to ensure all is well."
Do you have a SWR meter to do such a check. It is not among the standard tools I have on my boat.

 

[Don S/V ILLusion]

I wouldn't worry about swr as it can often provide misleading info to anyone unfamiliar with their limitations. For example, you could use a light bulb as an antenna and an swr meter would show everything is working fine.
The options you list are all fairly equivalent with a loading coil and mount so it's difficult to differentiate. Just make sure you properly install coax connectors using good quality coax and check for shorts prior to installation.

 

[Ken Cross]

I wouldn't worry about swr as it can often provide misleading info to anyone unfamiliar with their limitations. For example, you could use a light bulb as an antenna and an swr meter would show everything is working fine..

VSWR is the worldwide standard for antenna and transmission line testing. It's also one of the easiest and cheapest methods for testing reflected power. If you don't look at antenna and transmission line performance you have no idea how well a system is working. I wouldn't consider installing a new antenna without checking it. It's true someone could create a dummy load (using a variety of components) that would pass VSWR tests, but that's not what he's doing. I suggest anyone capable of doing your lightbulb test would certainly be able to check VSWR.

VHF is a primary safety system for most of us. I hear too many calls on the radio from people who think they can determine radio performance with a "Radio Check."
Now if you had suggested tuning in a weak station such as a weather channel at a known distance you may have an alternative check, but still really iffy in terms of estimating if your new antenna system is up to spec. You can easily be way off in characteristic impedance and be fooled into thinking it's fine. Even if the antenna is perfect, what about the ground plane, the coax, and the connectors? Did the antenna come properly tuned? Is there corrosion in a connection? You can't know without testing.
Ken

 

[Don S/V ILLusion]

Actually you would need an antenna analyzer to do most of the measurements described but to the point, don't be sucked into analysis paralysis when installing an antenna. If you have access to someone with an swr meter, great but it can give monumentally different readings when connected at the radio end or the antenna end so please rely on someone who knows how to use one. If no swr meter is available and the antenna is new and properly installed, it's unlikely to be a problem compared with bad solder joints on improperly installed connectors.

 

[Jacktar]

Go simple, try this one, got it at west marine, called a racing vhf antenna, about 25 bucks or so. Buy a boot for the cable connector from RV stores (about 2.50), marine dealers don't carry them for unknown reasons.

 

[The Garbone]

Have some of those Tram-1600s, no problem besides the one on the masthead being vaporized in a lightning strike. The one on my spreader (vhf) and the one tied to my stanchion (ais) with velcro seem to work just peachy.

 

[salishmermaid]

Yes, I have a VSWR meter and it currently tests high on the SWR and low on the power. Checking the resistance in the coax that at the bottom of the mast that is connected through the antenna reads closed circuit, which is why I am assuming the antenna is bad. It could be a bad connector, but I will check that once the antenna is removed from the coax and before mounting the new antenna.

I can communicate short range but only a mile or two as far as I can tell.

It was originally testing good for SWR and Power and not sure the distance but was getting loud and clear from Coast Guard on 22A. I was helping a friend trouble shoot his VHF issue and after hooking his radio up to mine and testing it then hooking mine back up I got bad SWR and Power readings. I don't think swapping radios could have caused the issue with the antenna, but just a coincidence and that both of our antennas were about 10 years old.

I originally thought it may have been a bad connection with the coax and fitting at the VHF, but after replacing the fitting it was still bad. Then I found the short circuit in the coax leading from the antenna, so I think the new antenna should fix the problem.

 

[woodster]

get the metz ......the coasties use them on all their vessels and they carry a lifetime warranty.......no need to bother with any other

 

[Don S/V ILLusion]

Yes, I have a VSWR meter and it currently tests high on the SWR and low on the power. Checking the resistance in the coax that at the bottom of the mast that is connected through the antenna reads closed circuit, which is why I am assuming the antenna is bad. It could be a bad connector, but I will check that once the antenna is removed from the coax and before mounting the new antenna.

I can communicate short range but only a mile or two as far as I can tell.

It was originally testing good for SWR and Power and not sure the distance but was getting loud and clear from Coast Guard on 22A. I was helping a friend trouble shoot his VHF issue and after hooking his radio up to mine and testing it then hooking mine back up I got bad SWR and Power readings. I don't think swapping radios could have caused the issue with the antenna, but just a coincidence and that both of our antennas were about 10 years old.

I originally thought it may have been a bad connection with the coax and fitting at the VHF, but after replacing the fitting it was still bad. Then I found the short circuit in the coax leading from the antenna, so I think the new antenna should fix the problem.

How do you know the apparent short is in the "coax leading from the antenna"?
Your antenna (and any antenna with a base loading coil) will show as a short circuit when tested with a voltmeter. The loading coil runs to ground at DC but is isolated at RF to serve to electrically lengthen the radiating vertical element. If you measured conductivity at the coax while connected to your antenna, you simply see the effect of the loading coil.

 

[salishmermaid]

That was one of my original question, if it should read an open circuit or closed, but I was just going by the specs listed with the Shakespeare 5215 that showed it should read as open circuit. I couldn't find a similar spec sheet for the Metz, so was just assuming it would be similar. My friend also bought the Shakespeare 5215 and it did test open. His old Metz tested closed, but I also assumed that was indicating the antenna was bad. Mine tested closed at the coax, but haven't removed it from the mast yet.

 

[Ken13559]

... you could use a light bulb as an antenna and an swr meter would show everything is working fine....n.

Don, you should have mentioned this earlier before I splashed 50 buck for an antenna. I've plenty of light bulbs! How nice it doubles as beacon whenever I transmit.

 

[CloudDiver]

I just got the Shakespeare 5215 because I wanted to be able to put my windex on it, I got the Davis model that is designed for it. Haven't installed it yet, but I like that I comes with a beefy stainless mount.

As far as the engineering behind which one to use... Unless you are a NOAA vessel you will probably never know or never care about any perceived signal performance difference. Any one of those antennas atop that 40 foot mast is going to give you about as much reach as your VHF wattage will possibly put out. Don't sweat it too much.