Any VHF guru's out there?

[Blue Crabber]

I am getting ready to install a fixed mount VHF radio in the boat. I have a 20' shallow "V" open bow boat that i use mostly on the chesapeake bay and some inland rivers. There is a pic in my signature.

I have decided on getting the West Marine VHF650. It is a class D VHF radio made by uniden.

Anyway, my question comes from the antenna side of the installation. What antenna do you guys think i should install? I was looking at an 8' fiberglass antenna but than wondered if that would be to big for my boat. The other option was a 3' stainless steel whip antenna.

Are there any other options that i should be considering? Or which one of these would be my best choice? My gut says go with the taller one for better distance but i don't know if that would be overkill or not.

Thanks for the help guys!

 

[Splat]

Re: Any VHF guru's out there?

Sorry but when it comes to VHF, size matters. VHF communication is line of sight so taller is better. There is no such thing as overkill. I would go with a 8ft fiberglass, and expect to pay for it. You can make a crappy radio perform flawlessly with a good quality antenna and cable, but can't make a top o line radio spit with a crummy cheap antenna.

Possiably look into a shakespere di-pole with 6db gain. They are available right here on IBoats

Bill

 

[Blue Crabber]

Re: Any VHF guru's out there?

Thanks for confirming my thoughts Bill.

Do you think that this antenna would be a good choice?

http://www.iboats.com/Shakespeare_G...2878252--**********.394155448--view_id.359265

Thanks again!

 

[P 0 P E Y E]

Re: Any VHF guru's out there?

Shakespeare makes an awesome product.

They have extraordinary customer service. I have called the 1800 number got great help on an antenna purchase.

It was a big antenna for our base radio and the guys steered me to the right product.

I would double check by calling just for the peace of mind.

 

[arks]

Re: Any VHF guru's out there?

Brandon-
I use the Galaxy 5225XP and it's a good antenna. Make sure you use a good mount. From past experience I recommend a stainless steel ratcheting mount like this:

 

[Boatist]

Re: Any VHF guru's out there?

I agree the 5225-XP is a great antenna and will make a world of difference over cheaper antennas.
That is a great price also.
Still your boat range will be just under 5 miles over open water plus the range of the other station.
Talking to another boat like yours with a antenna top of 10 or 11 feet above the water then will work to about 10 miles.
Talking to a station like the Coast Guard with a high mounted antenna can be 80 miles or more.
Out here along the coast Coast Guard antenna are on top of some mountains 3000 feet high and can reach them from 80 miles away.

When mounting your antenna of course mount so it can lay down on some support.
Also under the deck use a mountain plate for the bolts to go thru.
An aluminum plate 1/8 to 1/4 inch thick or at least the biggest washer you can find so the bolts do no pull thru the fiberglass.
Make sure when complete that the antenna is vertical while on the water.
I see lots of boat with the antenna layed back at an angle. I guess they think it looks cool but it also distroys the range front and back.
The antenna transmits in a narrow horziontal plane so for max range must be straight up

 

[waterinthefuel]

Re: Any VHF guru's out there?

I have a HAM radio license, general class, so I've had to study for and pass some significant tests on radio and how it behaves.​

I would respectfully sorda disagree with "taller is better." While that's true to a point, its not the catch-all end all of VHF. Altitude is your friend, not antenna height, with VHF. You also must consider antenna weight. On a small boat that can pitch back and forth violently in rough water an 8' antenna would snap off at the base whereas a 3' whip would be fine.​

I don't think you need an 8' antenna on the little boat in your photo. Mount a 3' whip it as high as you can and be done with it. A high-mounted 3' will outperform a low mounted 8' any day.​

I have an 18" HAM antenna on my truck and can hit a repeater tower 20 miles away on 20 watts perfectly. Again, antenna length is not that critical if you can mount a short antenna higher. I hope this makes sense.​

Think about this. An airplane's VHF antenna's are sometimes as short as 3 inches, but at 2000' altitude they can transmit to another plane at that altitude for 100 miles crystal clear. I've used a handheld tranceiver, inside of a metal airplane, and talked to another airplane 60 miles away on 5 watts with a stubby antenna.​

So the difference between 3 and 8 feet for a boat won't matter that much unless you're trying to absolutely max out your distance and range which, unless you're going offshore with it, you don't need to do. After all the difference is just about nill, a mile or two maybe. And a little 3' whip is a lot easier to deal with while on the water than the big radio free Europe 8' fiberglass telephone pole.​

 

[Blue Crabber]

Re: Any VHF guru's out there?

Thanks for all the replys everyone.

I will absolutely be using a good mounting device. I think i will use one like in your picture Arks, thanks.

I will also be using SS plates on the bottom under the fiberglass for reinforcement. I don't like to take any chances.

WaterInTheFuel - I completely understand what you are saying about antenna heigth. However I will not be able to mount a 3 foot antenna any higher on the boat than I could mount an 8' antenna. So in this case, I think taller will be better.

However, I think I will call Shakespeare just to double check with them.

Thanks again!

 

[Splat]

Re: Any VHF guru's out there?

I have a HAM radio license, general class, so I've had to study for and pass some significant tests on radio and how it behaves.​

I would respectfully sorda disagree with "taller is better." While that's true to a point, its not the catch-all end all of VHF. Altitude is your friend, not antenna height, with VHF. You also must consider antenna weight. On a small boat that can pitch back and forth violently in rough water an 8' antenna would snap off at the base whereas a 3' whip would be fine.​

I don't think you need an 8' antenna on the little boat in your photo. Mount a 3' whip it as high as you can and be done with it. A high-mounted 3' will outperform a low mounted 8' any day.​

I have an 18" HAM antenna on my truck and can hit a repeater tower 20 miles away on 20 watts perfectly. Again, antenna length is not that critical if you can mount a short antenna higher. I hope this makes sense.​

Think about this. An airplane's VHF antenna's are sometimes as short as 3 inches, but at 2000' altitude they can transmit to another plane at that altitude for 100 miles crystal clear. I've used a handheld tranceiver, inside of a metal airplane, and talked to another airplane 60 miles away on 5 watts with a stubby antenna.​

So the difference between 3 and 8 feet for a boat won't matter that much unless you're trying to absolutely max out your distance and range which, unless you're going offshore with it, you don't need to do. After all the difference is just about nill, a mile or two maybe. And a little 3' whip is a lot easier to deal with while on the water than the big radio free Europe 8' fiberglass telephone pole.​

Uhhhhhhh...... Yea ok, I'll agree with that. Altitute of antenna is what were looking for. Overall length doesn't matter as long as it's tuned for that/those frquencies. However mounting a 8' or a 3' in the same place, in theory the 8' will out perform the 3 strickly because it radiates and received at a higher altitude. This is often true of sail boats that use only a 3' antenna mounted atop the sail mast. This altitude in relation to the boat is also why they typically use a 3db gain antenna, with the waves moving the boat, the motion is exzaggerated 10fold at the top of the mast. 3db of gain means the antennas optium receive field is more open and broad, so as the boat pitches the antenna can "see" more signal.

I think that made sense.

Bill

 

[Boatist]

Re: Any VHF guru's out there?

First a 5225 antenna will not snap off from the motion of the boat. I hit trees with mine and it has survived with no damage. The 5225 has a large base and is very stiff.
I am also a Ham advanced class and yes you can reach a repeater 40 miles away but that repeater antenna is on top of a moutain or a tall building.

The main reasons sail boats use the 3 DB 3 foot stainless antennas is it light weight on top of the mast, also when the boat is healed over the 3 db antenna transmits in a much wider horziontal band so can still talk to boat on your beam.

 

[tawood]

Re: Any VHF guru's out there?

I'm also a ham, advanced class, and what "waterinthefuel" is forgetting is that the 8 foot antenna should have MUCH higher gain, something like 6 db, compared to 3 db for a 3 footer. This will make your signal pattern radiate more toward the horizon, less toward the sky. As long as the antenna is mounted vertical, it means much farther transmit range, with much better received signal strength from the horizon.
Tim -- KG8ES

 

[Thajeffski]

Re: Any VHF guru's out there?

First a 5225 antenna will not snap off from the motion of the boat. I hit trees with mine and it has survived with no damage. The 5225 has a large bass and is very stiff.
I am also a Ham advanced class and yes you can reach a repeater 40 miles away but that repeater antenna is on top of a moutain or a tall building.

The main reasons sail boats use the 3 DB 3 foot stainless antennas is it light weight on top of the mast, also when the boat is healed over the 3 db antenna transmits in a much wider horziontal band so can still talk to boat on your beam.

I also have an 8foot 5225 and there is no way it's going to "snap" off.....don't listen to whoever said that - totally doesn't know what he's talking about. I forgot to put it down once and hit it against a train bridge and all it did was make a bunch of noise. Couldn't even find a scratch on it.

 

[Expidia]

Re: Any VHF guru's out there?

I second what Ark and others have said about the Galaxy 5225XP can be found for $79, have iboats price match. I found mine in black too which is the color I wanted. Use the stainless steel ratchet too, as described by Ark forget those cheap nylon/plastic ones.

My boat small, but after reading up on it on various boating sites the only way to go is with an 8 foot.

My helm is small too, so mounting it near there would put it too close to the radio so I opted for a transom mount and just lay it down while fishing.

Mounting directions will give you the minimum distance between radio and antenna. Something like 36 inches apart I think.

Don't cut the antenna wire, just coil it loosely.

Best to solder the connector on but they make some nice gold crimp on's that can get you going quickly until you get a chance to solder it.

The 5225 also has a real small connector unlike others where you have to drill a bigger hole in your boat.

I went with the 8 footer and a fixed mount VHF after the first time I actually needed to call for assistance in the pitch dark while returning to a launch area my handheld was totally useless with it's 2 mile range in the mountains.

 

[Blue Crabber]

Re: Any VHF guru's out there?

Thanks for the help everyone. I will be going with the 5225XP 8' antenna. It may seem overkill to some, but better to have the extra feet than not! I figure if i move up to another bigger boat in the next few years, I will just move it over to the new one.

I didn't know about the antenna location compared to the radio, thank for the heads up Expedia.

Hope to have it installed July 4th weekend. (Next time to the boat!)

Thanks again!

 

[waterinthefuel]

Re: Any VHF guru's out there?

Ok, no I don't know what I'm talking about, it just happened to me! But I didn't mean snap off the bottom of the antenna, I meant break the mount. How do I know? It happened, but I was using a plastic mount. The way you are talking about mounting it with stainless steel and whatnot, yea, you'd be fine.​

And I never said a 3' and 8' mounted at the same height would perform the same. I said a 3' mounted high and an 8' mounted low the 3' would perform the same. You might not have any option other than mounting an 8' on floor almost whereas you might have the ability to put a 3' up on top the thingy that covers the center console area, a good 10' off the boat floor. In that case the 3' would outpermform the 8' simply from altitude.​

And no I didn't forget about the gain, but the gain is meaningless if the antenna is mounted lower. Gain ain't everything, ma friend. What YOU forgot about was this:

Antennas with a high dB rating concetrate signal energy perpendicular to the antenna shaft in a relatively flat wave form. This provides a more concentrated signal, but can also cause fading as the boat pitches and rolls. So if the OP wants his signal to fade in and out as his boat rocks back and forth, go ahead, use the 8'.

Unlike the others, I'll actually post information on what I'm saying, not just attack someone and say they don't know what they're talking about when they obviously do. Here is a nice link with some formulas for calculating VHF range. Unfortunately they don't put up a formula for a 3db gain antenna, but I've never heard of the formula changing much when gain goes up. But here it is anyway, I think this will help you figure out your expected range with the rig you plan on using.​

http://www.catfleet21.org/rigging/June.htm​

Square root of the height (in Feet) above water x 1.42 = range in miles.​