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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

VHF antenna

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seabreeze
Deckhand

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18 Posts

Initially Posted - 06/11/2009 : 08:19:47

I am installing a new vhf radio on my 1982 Catalina 25. I have a 3 foot antenna and am wondering if there is a good place to put a temporary mount, somewhere on deck, or do I need to mount it on the mast? I will be sailing off the coast of Calif. 20-25 miles from shore part of the time, and the rest of the year on inland lakes. What is your experience?
Thanks

Jim
C-25, 1982, SR,SK

Edited by - on

Rich P
1st Mate

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USA
77 Posts

Response Posted - 06/11/2009 : 08:28:29

VHF is line of sight. The higher the antenna, the further it will transmit/recieve (as long as you have the wattage).
Transmitting Receiving Antenna Height
Antenna height 5' __ 25' __ 250'
5 feet ______ 5 mi __ 8 mi __ 22 mi
10 feet ______ 8 mi __ 11 mi __ 25 mi
50 feet ______ 10 mi __ 13 mi __ 28 mi

Edited by - Rich P on 06/11/2009 08:30:25

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 06/11/2009 : 08:29:42

Jim,
If it were me, I'd mount it at the top of the mast. VHF is line of sight, and the higher your antenna, the longer your line of sight. If you're going to be sailing off shore in your boat, you want all the advantages you can get from your system.

It's not overly difficult to run coax through the mast, I've done it both on my C-250, and helped another C-25 owner to run pull strings through his so he could pull wires.

Edited by - on

Rich P
1st Mate

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USA
77 Posts

Response Posted - 06/11/2009 : 08:35:05

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

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Old Disco Queen
1st Mate

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USA
66 Posts

Response Posted - 06/11/2009 : 09:03:58

Just finished doing mine and placed it at the top of the mast. Be sure and use the "larger" wire so that transmision loss is less. Got mine at Catalina Direct and the "kit" was cheeper than over at West Marine (and included a new antenna for the same price). I did the "coax through deck" plug and it is Great!

Stephen

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aeckhart
Master Marine Consultant

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USA
1709 Posts

Response Posted - 06/11/2009 : 11:11:12

If you are installing the wire in the mast and want to get it through the pvc tube in the forward part, the backstay is long enough and fits nicely to pull the wire through. Of course, if you don't have the tube the backstay will work in the mast as well.

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jerlim
Master Marine Consultant

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USA
1484 Posts

Response Posted - 06/11/2009 : 14:22:34

With respect to heights and transmission ranges...last year I was hearing the USCG from Maryland...out at the tip of Long Island...something on the order of 250 miles...we were pretty impressed !

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seabreeze
Deckhand

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18 Posts

Response Posted - 06/11/2009 : 14:30:06

Thanks, guys. This is all very helpful!

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Prospector
Master Marine Consultant

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Canada
3159 Posts

Response Posted - 06/11/2009 : 14:57:33

Seabreeze, is it a regular, or high gain antenna you are installing? This can make a difference as High gain have a more directional pattern and may not work as well under heavy heel.

Edited by - Prospector on 06/11/2009 14:57:52

Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 06/11/2009 : 15:05:37

And search the forum for antennae, you will find numerous long winded discussions. My experience with a 3' whip on the stern pulpit (PO had it) was very poor, but others have been satisfied with a long whip on the pulpit. 3' at the masthead works fine.

Edited by - on

GaryB
Master Marine Consultant

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USA
4304 Posts

Response Posted - 06/13/2009 : 18:54:30

Do the handhelds have a way to attach them to a regular vhf antenna?

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Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 06/13/2009 : 19:00:41

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by GaryB
 Do the handhelds have a way to attach them to a regular vhf antenna?
<hr height="1" noshade id="quote"></blockquote id="quote">
Yes, some do. It depends on the model.

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Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 06/13/2009 : 21:06:29

But less horsepower (watts)

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GaryB
Master Marine Consultant

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USA
4304 Posts

Response Posted - 06/14/2009 : 09:12:01

Yeah I was looking around on the internet last night and noticed the most powerful handhelds are only 6 watts and cost as much as the full size vhf's.

My current handheld is 5 watts and seems to reach out four or five miles and pretty much covers the areas I sail day in and day out but I'd like to have the DSC capability and be able to reach the lower bay so I can contact my buddies. I'm also thinking of taking the boat offshore a few miles for a few hours now and then in the future. I'd rather have too much radio than not enough!

I don't want to hijack this post anymore than I already have so I'll move to a new post if I have anymore questions. Thanks for the responses.

Edited by - GaryB on 06/14/2009 09:13:36

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 06/14/2009 : 10:49:10

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by jerlim
 With respect to heights and transmission ranges...last year I was hearing the USCG from Maryland...out at the tip of Long Island...something on the order of 250 miles...we were pretty impressed !<hr height="1" noshade id="quote"></blockquote id="quote">They have an array of towers along the coast, and transmit with way more power than we're allowed to.

They can also hear a pin drop--I've reached them from many miles away with a handheld. For that reason, around here, they don't like Ch 16 being used for routine stuff. Once in a while they demand that a fisherman identify himself (while they're triagulating on him)... then all goes quiet.

An 8' (6 db gain) antenna on the stern rail will probably reach out about as far as a 3' (3 db gain) one on the mast-head. Some say 3 db is better on a sailboat because the transmit pattern is more spherical, so you loose less distance under heel. Higher gain focuses the signal in a flatter "disc-like" pattern. Contrary to popular belief, VHF signals can go over the horizon to a degree, and over land masses that block line-of-site. I can prove it any time from my dock. They just don't reflect off the ionosphere like SW. Sten, I and others had a discussion here on this a while back. You generally run out of wattage before you lose out to the curvature of the earth.

Sorry if this is a hyjack...

Edited by - on

seabreeze
Deckhand

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18 Posts

Response Posted - 06/15/2009 : 14:25:14

No problem, it's great to have all the info.

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