240 Sundeck, which VHF Attenna(s) is best?

[Morpheus]

Right now I have just a handheld VHF radio and would like to install something on the boat. I already have an idea on what radio I want (Thanks Jim at BOE) but I'm still not sure on which antenna(s).

I'm thinking I want 2 a short and a long. The short for when we are staying close to shore or not going out in the harbor or bay, the long for when we go further off shore and need more range.

I'm thinking Shakespear Jim at BOE recomended the 528 4' but should I get a 4' and 8' or a 4' and something shorter?

Of course I need a backet that I can lay the anttena down and also be able to easly remove and put on either antenna at any time. (I won't forget the shims so that it's straight for Gary)

I have about $200 in Boatersworld cards that I'll probably use (sorry jim) as they offer a warranty on antennas so that if you do anything to them they will replace them like snap them off on a bridge or something. I'll be getting the radio from Jim for sure.

So I just need your nice boaters expert knowledge on which antenna or antennas to get.

 

[Woody]

How far away from shore might you go? I would think coastal fl is very well covered by CG. Changing antennas would be a hassle. If you did put a 8 footer on your 240 it wouldn't look bad.

 

[Morpheus]

Well if I know I'm only going out in the bay or the harbor not far from shore I'd rather not have a big antenna wiping around I was thinking.

As far as how far off shore no farther then the radio will let me I might go out far enough where I can't see the shore line just so I can say I did it and to see what the water and waves are like (of course if it starts to get dangrous I would head back)

 

[First Born]

But the tallest and straightest that you can get your wallet around :smt043

 

[Woody]

my 270sd with 5' antenna, 8' would have looked ok

 

[Four Suns]

Changing your antenna out is not something you are going to want to be doing all the time.

There are basically three things you need to concern yourself with for range of a VHF radio: 1. radio power (wattage), 2. antenna height and 3. Gain (dB) of antenna. All three of those work together and will determine if someone can hear you or not. Remember, however, that just because you can hear someone doesn't mean they can hear you.

I'll assume you are talking about a built in radio so your wattage will be much better than a handheld. As far as antenna height, remember that VHF is "line of sight" so generally speaking, the higher the antenna, the better. It also means that once you are out of sight of land, your reception/transmission capability goes away. It's actually measured from around the top of your antenna to the top of the other antenna you are communicating with and land based CG facilities generally have pretty tall antennas. However, for all practical purposes, 20 to 25 miles is about all the range I get on my VHF and I have some tall antennas.

The last thing that will determine your range is the antenna gain. VHF antennas are typically rated from 3dB to 10dB (sometimes 9). The lower the gain, the wider the angle the signal radiates from the antenna. For example, a 10dB antenna will give you greater range than a 3dB antenna but it is far more sensitive to the antenna being vertical due to the tighter radiating angle. So if you have a smaller boat and are going to be rocking a rolling in 6 foot waves, a 10dB antenna isn't going to work very well and a lower dB antenna will do much better even though the range is decreased. Most smaller antennas (3-4 feet) are rated in the 3dB range, 8 foot antennas are usually rated around the 6dB range, and 16 foot antennas are usually around 9-10dB. The ideal situation IMO on a bigger boat is two VHF radios with one on a smaller lower dB antenna for short range/rough seas and a longer higher dB antenna for long range/off shore use.

At the end of the day... put an 8 ft 6dB antenna on your boat and you'll be happy with it.

You could, however, put a Single Side Band radio on your boat and talk to folks over in Europe....

 

[Morpheus]

Thanks Gary for your knowledgable input I promise to make the antenna straight as possible :grin:

I'm still curious why you say I don't want to be changing antennas? I'm not talking about taking both with me out on the water and doing it there. I normally plan where we are going and where we will be before we go and leave a float plan like all good boaters should so I know in advance which antenna I might need. A 16' antenna would look real redneck like on my 26' boat so I was thinking max an 8' but maybe just the 4' but like you said it's line of site. 20 to 25 miles off shore in my boat sounds like suicide, isn't like 1-2 miles off shore before you can't see it anymore?

This is what I'm looking at getting as far as the VHF radio.

http://www.byownerelectronics.com/store/product.php?productid=17277&cat=0&page=1

http://www.byownerelectronics.com/store/product.php?productid=32512&cat=0&page=1

I plan on reconfiguring where the radio is (I believe it's the star-board product) so that both the radio and vhf fit inside the storage area in the helm and then use just the remote mic at the helm so that I don't have to have that LARGE radio in the way all the time.

I'm going to hopefully DIY this I think I can I did my Garmin GPS myself so should be a problem (man I hate drilling wholes in a boat)

Anyways that said can anyone elaborate on why I wouldn't want to just have 2 antennas that could be easliy changed out before each trip out?

 

[Woody]

When I added my vhf radio I moved the trim tab switches to the starboard side gunnel. I then enlarged the cutout where they used to be and flush mounted the vhf there.
The difference between the 4' and 8' antenna is not going to increase your range by much. Shakespeare says take the sqaure root of your antenna height above water x 1.42 and that will give you an approximate range. It just doesn't seem worth the additional costs and hassle for little gain. I suppose you also run the risk of damaged or otherwise poor connections due to changing antennas frequently. About the time you make a mayday call is when that one will show up.

 

[Morpheus]

Yea went to boaters world with my $100 gift card in tow, looked at the antennas 8' just seems so dang long and is about $50 more then the 4' and I'm thinking 4' will be enough for me even if I go off shore a couple of miles. 1.42 * 4' = 5.68 (miles?) seems a bit far even if I got half that out of a 4' antenna I'd be happy. I realize there are other things that affect it.

Thanks for the idea woody on moving the trim tabs, I still think I like the idea of having that remote mic, I was thinking of running the cord out of the storage area next to the throttle and put a hook there to hang it on. I went to MM today (closer then goign to wher the boat is) and measured the Star Board in the helm there which is 20" so I can order some new and fabricate it so that the radio and vhf fit in the storage area under the helm.

Again the only reason I was going to get the antenna from boaters world is that for $30 they give you a 1 year warranty that if ANYTHING happens to the antenna bring it in and they will replace it, the guy even said even if there is nothing wrong with it just before your year is up go ahead and snap it in two and bring it in for a new one. Warranty is even renewable every year.

 

[PMvdb395DA]

You could, however, put a Single Side Band radio on your boat and talk to folks over in Europe....

Hello? :smt015

 

[Morpheus]

Ok here is the next question do I go with the

Shakespeare Galaxy 5400-XP
4' VHF 3db Gain Antenna

OR

What Jim recommeded

Digital Antenna
4' VHF 4.5db Gain