VHF and Other Antennas

MikeD@Lightningshack · Post by **MikeD@Lightningshack** » Oct 22nd, '07, 12:12

Guys,

I was getting ready to install a new VHF antenna on the Lightningshack this weekend and got talked into re-thinking by a fellow betram 31 owner.

I have a freshly gelcoated bridge and new hardtop with a full enclosure.

I was going to use the standard 8' extension poles, and 6' antennas from Shakespeare. These would mount with the swivel bases on the side of the bridge, and be supported by rupp antenna supports that have already been welded to the hardtop. I was going to install 3 antenna. 2 VHF and one FM.

My buddy was appalled that I was going to add all this clutter and junk to the new clean glecoat and hardtop installation. He claimed I could get a 36" stainless steel VHF antenna whip from Shakepeare that would work every bit as well and could be attached to the hardtop without cluttering up the boat with extension poles and large antennas.

Since he stopped me before I drilled a hole, I thought I'd put the antenna install off for a couple days to re-evaluate.

Is there a tangilble advantage to having the tall antennas? Does it really make a noticeable range difference? Are they really that ugly? (YES, I think) Does anyone use the short 36" stainless antennas from shakespeare... Do they work well, will I get similiar range?

It would be a pain, but I could probably manage to pull a few more antenna wires up through the frame work, so the small ones could be securely and cleanly mounted on top.

What are your thoughts?

Thanks Again,
Mike Dolan
www.lightninghshack.com

In Memory of Vicroy · Post by **In Memory of Vicroy** » Oct 22nd, '07, 13:24

Mike - the stubby stainless base loaded antennas (the original was the Metz Six) are a sho-nuff 6 db gain antenna and work real well as long as you seal the PL 259 connector on the bottom to keep water out of them. Since VHF radio waves are line-of-sight, the higher the better. I use the 21' Shakesphere 9 db gain and it works a good bit better, but the base loaded stubby is still a good antenna. It has a coil of wire in the base that makes it think it is a longer antenna, and as long as you can keep water out of it, a OK deal.

My preference is still the 9 db gain tho.....

UV

Capt. DQ · Post by **Capt. DQ** » Oct 22nd, '07, 13:48

Mike,

Depends really on how you are using your boat? If you are fishing offshore, like UV says having a 9db antenna is good to have for distance & 6db antenna is the norm of most and height is better for over water.

One of each is good, but with satellite cell phones today, some are also getting those for extra security in emergency's along with your gps satellite e-birups.

They also have better grades of antenna's with better internal grades of material, don't buy the the cheapest because...price is long forgotton when your in need of help.

DQ

mike ohlstein · Post by **mike ohlstein** » Oct 22nd, '07, 13:49

I use a six foot 9db on one radio and a three foot 3db on the other. I find that there are times when the 9db is too directional to pick up broadcasts from 300 yards away, even though it will pick up something from 20 miles away.

An A/B switch would do the trick if you have only one VHF, but I would get one of each antenna if venturing off shore.

Things break. Two are better than one.

Mike

In Memory of Vicroy · Post by **In Memory of Vicroy** » Oct 22nd, '07, 16:47

The technical answer is that most all VHF antennas are quarter wave.....in simple language for you Hatt owners, the antenna length is one quarter of the wave length of the radio wave, in meters....since VHF operates on 158-161 mega hertz, the wave length is pretty short. The trick is to get the SWR (standing wave ratio) as low as possible, say to 1.2 to 1. You do this by using real good coax cable (RG-9, the thick stuff) and good solder joints on the PL 259s. You can buy a SWR meter for short money and see the results of good workmanship.

Now on the other hand, I like my 23' sideband antenna with the automatic tuner hooked up to the 150 watt Icom 802 SSB and the Garmin GPS that will tell the CG where to find my body anywhere in the world.

Bottom line is good cables, good solder job will make a huge difference in how your radio works...oh yeah, and get plenty of 12v DC power to it...if the lights dim when you key the mike, run another wire to it.

UV

Dave Kosh R.I.P. · Post by **Dave Kosh R.I.P.** » Oct 22nd, '07, 22:23

UV is right on the money again. By the way with only 85 sq. ft. of copper screen my sideband works very good Vic. I will add more screen yet.
It's off to Zion , Ill. tommorrow for a week as they evaluate and treat me. That's Midwest Regional Medical Center the first Cancer Center of America hospital. My bride wanted to go to Lauderdale this year but priorities and besides she found out you were not going to be there also.
Higher the better on VHF antennas. Dave K

Rawleigh · Post by **Rawleigh** » Oct 22nd, '07, 22:25

God speed Dave!!!

IRGuy · Post by **IRGuy** » Oct 22nd, '07, 23:00

Here is a one page summary of all you need to know about marine antennas....

http://reviews.ebay.com/VHF-Marine-Radi ... 0000015940

IRGuy · Post by **IRGuy** » Oct 22nd, '07, 23:02

Dave...

Will be thinking of you and sending you all the good vibes I can muster!

Mikey · Post by **Mikey** » Oct 23rd, '07, 10:59

IRGUY,
Great site. Just in the nick of time as I research antennas and electronics for Dreamsicle. Too many choices. Planning this boat for fishing and travel on the Bay only so that does help some.

IRGuy · Post by **IRGuy** » Oct 23rd, '07, 11:50

Mikey...

I was late for you on Optima batteries, but glad I am on time for your antenna issues!

Carl · Post by **Carl** » Oct 23rd, '07, 16:39

Sending a few prayers your way Dave.
Carl

Mike Moran · Post by **Mike Moran** » Oct 23rd, '07, 18:25

Dave I will put you on our prayer list in AM. hang tight Mike

MikeD@Lightningshack · Post by **MikeD@Lightningshack** » Oct 23rd, '07, 18:27

Guys,

Thanks again for all of the help.

I think I am going to ditch the 8' extensions.

I will pull some more cable through the hardtop frame and will install 1 6db, 1 3db, and 1 AM/FM antenna on the hardtop.

The extensions poles would only push the 6db antenna up 2 or 3' higher then mounting directly to the hardtop.

I don't think the additional hardware is worth the slight range increase.

Thanks again for your help.

Mike Dolan
www.lightningshack.com

Mikey · Post by **Mikey** » Oct 24th, '07, 10:40

Mike,
Good stuff on Lightningshack, she looks fine. What are the small lights in the ceiling of the main salon?

For all looking to replace antennas might want to check prices at:
http://wholesalemarine.com.
For lighting Imtra is currently having a sale with big savings:
http://imtra.com

Rawleigh · Post by **Rawleigh** » Oct 24th, '07, 13:54

Mikey: The Digital antenna's are very good. I have one of their 4 footers. Very good quality. David Nova runs one on his 34 Fountain tournament fishing boat and has had good range with it offshore.

Chiles · Post by **Chiles** » Oct 24th, '07, 14:49

I would ditch the AM / FM antenna in favor of a Sirus satalite antenna that matches your GPS receiver. I used one of those in line FM converters on my standby VHF antenna so could receive FM or AM. Since I went to Sirus, I have never even bothered seeing what I could tune in while out in the bay. Both VHF's were carefully installed with soldered connections and had an extra layer of sealant applied. Not to mention the Cx being applied everywhere.

Maybe I'm silly but I like the symmetry and the redundancy. My VHF's are the 6' Shakesphere VHF models and work great.

MikeD@Lightningshack · Post by **MikeD@Lightningshack** » Oct 24th, '07, 18:22

Small Lights in ceiling of Salon...

They are for illumination... I use the boat at night. Chunking trips and just hanging around the marina in the evening.

The small halogens really make the teak sole stand out too.

Nothing more then aesthetics I guess.

Thanks for your comments, I will get some new pictures of the hardtop and enclosure up soon.

Mike

scot · Post by **scot** » Oct 24th, '07, 21:23

Hang in there Dave there is a lot of people praying for you.

On the antenna subject, I agree with the article 100%...it's very difficult to beat a high mounted, long wip. As stated in the article these radios work off line of sight and the higher the antenna is, the greater distance you can communicate. This is a general rule and of corse does not negate all the other factors mentioned.

UV's SSB is the way to go if your going way out, or a good sat phone, the price for the service is coming down every year....Plus if you have to ditch you still have communications.

nestorpr · Post by **nestorpr** » Oct 24th, '07, 23:17

Ditto Dave, Godspeed!

bertram31.com

VHF and Other Antennas

VHF and Other Antennas

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