VHF Antenna Replacement

3

300sflyer

Chief Petty Officer
Joined
Jan 1, 2009
Messages
610
I have discovered I need to replace a 15 year old broken VHF radio antenna. The current one I have is a 8' Shakespeare 5206-N. Should I just replace it with the same one, or are there better ones now available?

Thanks
 
Fireman431

Fireman431

Rear Admiral
Joined
Sep 17, 2007
Messages
4,292
Re: VHF Antenna Replacement

The need for which antenna depends a lot on how far from shore/other boaters you are. If you usually boat within conventional waterways and don't stray too far from civilization, the standard antenna will be more than adequate. The farther out you are, the longer antenna you need. How far your radio transmits is based on the radio, not the antenna. The antenna is for reception. They operate on a line of sight basis.

That being said, I would still go with the better antenna. I just wanted you to know it wouldn't make your radio any stronger. Also, when you buy the new antenna, you'll have to solder the connector on the end so run the cable first, then put the end on it.
 
Boatist

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: VHF Antenna Replacement

I also like the 5225-XP or the 5225-XT antennas. Both have solid brass or copper radiators and the XP is sliver plated. Copper is a good conductor and silver is even better. Both also come with better Coax It is RG8X instead of RG58.
I started with a cheap flexible 8 foot 6DB gain antenna and it worked fine. But fishing offshore in open waters often I would be near another boat and they were picking up stations I could not receive. Later I upgraded to the 5225-XT antenna and I could here twice as many stations. In the camp ground that is next to a good launch would be mostly boater during the fishing seasons. I got to know a lot of the boater that were there year after year and many now were coming up to me saying I could here your radio picking a station I could net here.
I am also a Ham Radio Operator and have a lot of test equipment so I started taking it to the ocean camp ground when we go there along with 35 feet of Coax. When people would ask me about why I could here more stations then I would tell them when we get the fish cleaned and boat dry pull your boat over to my location and I can test your antenna Standing wave ratio and also hook you. up to my antenna.

Everyone helps everyone there with a few exceptions. Many of the station I checked had stand wave ratios over 3 to 1. So we would try and find the problem. Many had Coax problems. Some the PL259 was not installed right. Either they shorted when soldering or the braid was not connected. Some coax was cut where it went thru the deck or broken inside where it made too tight a bend when lowering the antenna. Also many of the more felexable antennas had problems with the radiators inside the antenna. You could flex the antenna some and it would be pretty good let it go or shake it and the SWR would go very high.
Most with internal problems I think were antenna that used tuned Coax as a radiator.

Fixed VHF radios all are 25 watts of power with a switch for 1 watt for in port or close range. The Range comes from antenna height. For most recreational boats a 8 foot 6 DB gain antenna is best. Mounted on a deck 3 feet above the water give you a range of 4.71 miles plus the range of the other station. So boat to boat is almost 10 miles. Boat to Coast Guard where I boat is over 80 miles because their antenna is on top of a 3000 foot high mountain. Coast Guards task called Rescue 21 is to be able to receive a 1 watt DSC broadcast on channel 70 out to 30 miles for the entire Coast of the USA.

The antenna is use for transmission and reception. Increasing antenna height will increase your range. More power from the radio make almost no difference in range.
An antenna top 25 feet above the water range is 7.1 miles plus the range of the other station.

The formula is square root of antenna height in feet above water times 1.42 = Range in Miles. Then add the range of the other station.
 
AgentJ

AgentJ

Petty Officer 2nd Class
Joined
Feb 4, 2011
Messages
110
Re: VHF Antenna Replacement

I could not have said it beter myself! Bottom line up front.... Its all in the antenna.
W7CID
General ticket.
 
3

300sflyer

Chief Petty Officer
Joined
Jan 1, 2009
Messages
610
Re: VHF Antenna Replacement

Thanks for the info guys! That helps a lot! :)
 
J

jhebert

Ensign
Joined
Jul 24, 2005
Messages
902
Re: VHF Antenna Replacement

Your original antenna, the Shakespeare 5206-N, is perhaps the least-expensive VHF Marine Band antenna made, and somehow it gave you 15-years of service until you mechanically damaged it beyond repair. I'd say that is substantive evidence that the Shakespeare 5206-N is a good antenna for your application and provides a long and useful service life, as long as you don't mechanically damage it. However, in contrast you've been given advice to buy much more expensive antennas that offer little advantage--the suggested antennas can also be mechanically damaged and are not likely to last any longer than the 5206-N's 15-years of good service. I don't know that you need to spend five-times more for an antenna. Just get another 5206-N.
 
A

azboater2

Seaman
Joined
Apr 5, 2011
Messages
53
Re: VHF Antenna Replacement

I completely agree with jhebert. The antenna lasted 15 years, just replace it. According to Shakespeare's web site the 5206-N is a 6db gain antenna, and the 5225-XP is a 6db gain antenna. This figure means that the ERP in the horizontal plane is 99 watts from a 25 watt VHF radio. That's very important, and BOTH antennas are rated at 6db gain, so use which ever one makes you happy, there going to talk exactly the same provided, as boatist says, that both are clean installations. It is also interesting that the 5206 has a rated SWR of 1.3:1 @156.8 MHz (Channel 16), while the 5225 is nominally 1.5:1 at 156.8 MHz, also of note the 5206 has a 5 mhz bandwidth compared to the 5225's 3 Mhz bandwidth. Now both these ranges fall well within the marine band of frequencies (156.050-157.425), but the 5206 will maintain a bit flatter SWR while switching channels. Higher SWR means lost power reflected back from the antenna. Some of my friends actually choose the 5206 for just this reason because we also need to talk on Coast Guard frequencies 150.700 and 149.200 and the 5 Mhz bandwidth of the 5206 just squeaks in there and still works pretty good. Of course the 5225 is a better made antenna and will last much longer in rough conditions. If I were going off shore the few extra dollars would not be a big concern as opposed to making sure it didn't fall off the boat. So everybody's right, you need gain, you need power, you need antenna height, you need a clear view, you need a good clean installation, because in the end you need enough signal at the RECEIVING antenna to overcome the background RF noise to be heard and understood. PS: After all the advice you got here, make sure you have a solid 12 volts at the radio power plug, as close to the radio as possible, ON TRANSMIT. If your wiring is too small or has bad connections and your voltage drops to 10 volts when you key the mic, everything you just learned here just went out the window.


B. Hershey
Technology & Communications Mgr., Yellow Cab Company
KF7BVO - EXTRA, Marine/Aviation/Radar: PG1137634
U.S. Coast Guard Auxiliary 11S, D10-F7
 
Boatist

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: VHF Antenna Replacement

Great that we get both sides here as that is what this site is about.
Ok if I was going to buy the 5206 I would not get the 5206-N.
The N means it has a Nylon mounting Ferrule. The Nylon mount if your boat stays in the sun without a cover does not last long before the sun drys it out and it cracks an falls over board hanging by the coax.
Instead get the 5206-C which is Chrome-plated brass ferrule with standard 1"-14 thread. It Cost less than a dollar more.
5206 is An economical and lightweight, self-supporting antenna for good communications where Range is not the Predominant Factor.
It has a Quality copper cable elements for good range and efficiency.
This means it has some tuned Copper COAX for the Main Radiator Element. This is the type I seen most problems with the antenna it self, But then again I talking Pacific Ocean where 8 to 9 foot Swells 8 seconds apart are common all summer long. Plus winds of 25 knots and a Flexable Antenna that flexes lile a wet noodle all day long. Also want to talk VSWR ratios. Put your meter on it and you will find out the SWR changes a lot when the antenna is bent. Also then the radition pattern changes alot. It is no longer horziontal one second it transimiting to airplanes and the next it is submarines. Coax runs are short but it use higher loss Lower Quality RG58 Coax.
This may be fine for slow boats an sheltered inland lakes. The 5206 has a 2 year warranty. Price $30.


Shakespeare Galaxy Style 5225-XP
8' VHF 6dB Gain

Collinear-phased 5/8 wave elements

For the toughest of the tough jobs, Shakespeare introduces the extra edge of silver plated elements on world-renowned, world class, Galaxy marine VHF antennas. The new 5225-XP is a maximum range antenna built in a Shakespeare extra tough fiberglass radome. It's designed to withstand the wind forces and high speeds when used on hard tops, T-tops, and radar arches. The silver plating adds extended performance for extra reliable communications. The antenna's legendary Galaxy? high-gloss finish assures that it's welcome aboard.

Copper and silver plated brass elements for extraordinary range and efficiency

Stainless steel ferrule with standard 1"-14 thread

20' RG-8/X Low-Loss cable plus a PL-259 connector

Suggested mount: Shakespeare 4187

Shakespeare Limited Warranty: 5 YEARS

Silver Plated Elements Extended Performance

This antenna is $121 but it will perform better especily when conditions get bad and you need to be heard.
I consider this a very important saftey iteam on my list but if I was only and inland boater where it is very unlikely you will encounter Life threating conditions it may not be worth it.


http://www.iboats.com/Marine-VHF-Antennas/dm/*******.646659923--**********.174535642--view_id.248106
 
A

azboater2

Seaman
Joined
Apr 5, 2011
Messages
53
Re: VHF Antenna Replacement

Exactly on the nylon Ferrell. I had one break on the way to the lake! Not worth the hassle of saving a few bucks on the mount. I'm still using a nylon mount on my cell antenna, but it's not as heavy, and I'm still cheep, till that one goes that is. They do make a 9 db gain antenna, which is a lot of gain, but I have heard that the horizontal pattern is so tight it can fade in heavy swells. I've never seen the chart though. I have a 9db gain base antenna up on Mount Lemmon Arizona for work, and we tilted it a few degrees down because it was at 9900 feet and there was not enough gain near the mountain. I just think a lot of the antenna hype is marketing, but then again, I'm looking at it from an inland lake point of view. Most important though, make sure you have a VHF and that it is working, on ny size boat, it beats the heck out of a cell phone when you break down. Amazing how many fellow boaters come to help sometimes, and in the Auxiliary we tow for free if we can hear you.

You know if you can get that for $121 compared to maybe $60....a guy might just have to save for another two weeks :)

Hey, it gets life thretening sometimes, but I can still see the shore ;)

B. Hershey
Technology & Communications Mgr., Yellow Cab Company
KF7BVO - EXTRA, Marine/Aviation/Radar: PG1137634
U.S. Coast Guard Auxiliary 11S, D10-F7
 
3

300sflyer

Chief Petty Officer
Joined
Jan 1, 2009
Messages
610
Re: VHF Antenna Replacement

I now have a 5225-XT installed, and it is working well. :)

Thanks guys.
 
You must log in or register to reply here.
Top