posted 10-22-2007 04:36 PM ET (US)        

Which 8 foot VHF antennas are deemed the best of their class?

FYI, I heard the ICOM M604 won this year's NMEA award as the best VHF radio.

posted 10-22-2007 06:01 PM ET (US)            

One thing to watch is the length of the cable. Their cheap
VHF antenna has a 15' cable, which won't make it from the
aft end of the side rails to the radio. The Galaxy has a 20'
which will, with a couple of feet to spare.

Antennas aren't a rapidly changing market. Practical Sailor
did a comparison a while back, and the Shake 5225-XT did
well.

posted 10-22-2007 07:54 PM ET (US)            

I currently have a Galaxy 5225 XT Shakespeare mounted on my 170 Montauk. I too have sent and received responses from 20 miles away with my ICOM 402, too bad it's broken.

I have an appointment with and marine electronics shop on October 31 to purchase and install an new VHF radio. The electronics guy said that they will check my current antenna and if it is not up to par they will recommend replacing it with a Digital Antenna model 529. He said since I'm getting a top-notch radio, I should also have a top-notch antenna.

http://www.digitalantenna.com/prods/vhfantenna_8.html

I had read somewhere that the Digital Antenna 529 won the 2002, 2003 and 2004 NMEA award as the product of the year.

I enjoy fishing/boating alone in the ocean. My favorite fishing spots are up to 40 miles away from port so I don't mind spending a few more bucks to get a radio/antenna that is top notched.

Thanks,

posted 10-22-2007 09:56 PM ET (US)            

The GAM Electronics antenna bears some discussion, as Jim's (and HOME ASIDE's matching set) is one of the best radio's I've heard on the water. I don't know if it is from the radio itself, or the antenna, or a combination of both...the signal from their boats is *C R Y S T A L* clear. The only complaint I have is that the VOLUME of their transmittal is low.

However, I don't have any information about how those setups RECEIVE signals.

I do know that I can often hear boats 20-25 miles away on Lake Michigan on the 5225XT.

posted 10-22-2007 10:13 PM ET (US)            

http://continuouswave.com/ubb/Forum6/HTML/000985.html

http://www.gamelectronicsinc.com/tg.html

Do I want a 12 foot antenna on a 170 Montauk?

http://smg.photobucket.com/albums/v665/warrent/Montauk170/?action=view& current=Montauk4-10-04031.jpg

Note where my antenna is currently mounted on my console (click on picture to enlarge). Do I need a 4-foot extension? It looks like the base of the current antenna is obstructed by my console and occupants of the boat. I suppose any antenna would work better if the base of the antenna has an unobstructed line of sight.

posted 10-22-2007 10:49 PM ET (US)            

I see, a 4-foot extension with a 4-foot GAM whip antenna.

posted 10-23-2007 12:35 AM ET (US)            

This will give you a very clean installation and gain you some elevation over where your mount is now, and you will still be able to fold the antenna down to put a mooring or console cover on without interference.

posted 10-24-2007 12:30 AM ET (US)            

I would not drill a hole in the rail. I'd just tiewrap the
cable to the outside of the rail. Now, I do grab the
shepherd's crook to pull myself and full SCUBA gear up.

The Digital 529 did not do as well as the Shake in the
Practical Sailor test.

If your towing config will allow it, do a Shake on a 4'
extension. You may need to extend the coax though.

Chuck

posted 10-25-2007 08:26 PM ET (US)            

I hear you about the antenna being stressed in rough waters.

I actually velcro my antenna at the top of my console rail for additional support. (Not shown on the photo below.)

http://smg.photobucket.com/albums/v665/warrent/Montauk170/?action=view& current=Montauk4-10-04031.jpg

Warren

posted 10-27-2007 12:13 PM ET (US)            

Shakespeare 396-1

This antenna is a five-foot antenna in a fiberglass housing. Electrically it is a half-wave antenna, the same length as the GAM SS-2. However, this antenna utilizes a different feed technique--center-fed. There is one problem with a center fed vertical dipole: decoupling the feedline. The Shakespeare 396-1 accomplishes this with a half-wave coaxial sleeve.

The one thing I love about this antenna is your transmitter power goes directly to the radiating element. There are no shunt matching stubs or other devices. Your 25-watts go down the feedline, right to the radiating element, and right into the ether. This is known as a series-fed antenna. Many vertical end-fed antennas have to employ a shunt element in the matching network to permit proper impedance matching. This simple Shakespeare 396-1 has none of this, and therefore there can be no losses in the matching network.

The only disadvantage to the vertical dipole with sleeve decoupling is the potential for antenna currents to flow onto the feedline and distort the pattern. We never see any precise vertical radiation pattern measurements of Marine antennas, anyways, so to speculate that this one suffers more than any other style is not justified. If the decoupling sleeve is well designed, it should suppress this tendency.

The Shakespeare 396-1 is a ruggedly constructed antenna and it is claimed to be used extensively in Coast Guard vessels. The Shakespeare brochure says, " [the 396-1] is probably the most widely used antenna on Coast Guard vessels."

In my own installation I did not opt for this antenna because I wanted to elevate the antenna on a four-foot extension, and I thought that the weight and wind loading of this antenna would be too great for my existing ratchet mount and the light-duty extension I planned. Also the feedline exit at the base is not good for mounting on an extension.

I have not seen any test results from this antenna, and my interest in it is based primarily on my attraction to its very simple electrical design. I think it will give a good account of itself if mounted to advantage, that is, in the clear and not surrounded by metal rails and people. The implied endorsement from the Coast Guard is also a positive influence.

posted 10-27-2007 12:23 PM ET (US)            

An advantageous arrangement for an antenna mount on a center console might be to use a 4-foot or 5-foot fiberglass antenna, mounted to a 4-foot extension. Because of the heavy loading that an all-fiberglass antenna creates, the base mount will have to be supplemented with support bracket.

Locate the support bracket as high as possible on the center console. Locate the antenna mount at least one foot lower. This will give proper support and allow a heavy duty 4-foot extension to be use. A 4-foot or 5-foot antenna can be mounted on the extension. The extension is not part of the antenna, and, if of heavy duty rating and well supported by the mount and bracket, the extension could also function as a grab rail.

posted 10-28-2007 01:58 PM ET (US)            

the higher the antenna is mounted the better it will work

the lower the frequency the longer the antenna will be

the higher the gain of the antenna the narrower the beam
width will be

the more directional the antenna is the higher the gain
will be (yagi)

The installation and placement should determine which antenna is selected. For instance if you are using a bimini top will the antenna be out of the way? On my 150
Sport this was an issue, so I mounted the antenna to the port gunnel with a ratchet mount and used a 4' extension so that when raised the baso fothe antenna is about even with the top of the bimini. When folded forward it rests on the edge of the bench seat and is tucked into rod holders on the port side out of the way.

If I were to mount an antenna to a center console I would have to consider a ratchet mount with an upper yoke support, this takes a great deal of stress off the single point mounting. I would also prefer that the actual antenna is elevated as far as practical, so I would use either a 4' or 8' extension. I chose to use a base loaded steel whip similar to the GAM antenna made by Shakespere with the included 1" 14 thread mounting and about 36" whip. You could use a 4' or 8' fiberglass antenna on top of the extensions as well but the overall length might be too cumbersome.

On a T top I would consider whether I needed to fold the antenna down or not, if clearance was not an issue then an 8' antenna would be perfect. If clearance is an issue then the 3 ft base loaded coil with a spring may solve that problem.

Truth is if properly installed all of these antennas will work well. I would not be overly brand concious but instead would be application concious.

Interesting to note that both Jimh and myself were/are broadcast engineers and both use the 4' extensions with base loaded antennas. There are a lot of myths about antennas out there and spending more money may not yield any better results, a good well thought out installation will help the most.

Steve

posted 10-28-2007 02:36 PM ET (US)            

A 4 foot antenna which is unobstructed may work as well if not better than an 8 foot antenna that is obstructed by a center console, people, motor, etc.

The higher the base of an antenna is mounted the better. There would be less chance of obstructions the higher you go and the line of sight for the antenna will be further.

If I add a 2 foot base extension to my existing antenna it will extend off the bow by 2 feet in the down position. I think 4 feet is too much length to stick out off the bow in the down position.

Or I can just leave everything alone.

I hate making decisions.

Thanks,