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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Mast mounted VHF & Antenna

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Erik Cornelison
Navigator

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USA
194 Posts

Initially Posted - 12/12/2018 : 20:44:32

So how is your boat setup and do you like it? What would you install today?

My boat came with a VHF installed, but my antenna is rail mounted on the starboard aft side. I�m not replacing the VHF, just the antenna (it�s the wrong type). I have two handhelds radios as backup.

I�m going to run a cable through the mast and mount a new antenna up high.

What do you have for antenna & cable?

Where did you mount your antenna?

How did you connect to the mast base/ cabin?

Erik

Erik Cornelison
6th Generation Professional Sailor, First Gen Submarine Sailor.
1986 Standard Rig SW. #5234

islander
Master Marine Consultant

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USA
4012 Posts

Response Posted - 12/13/2018 : 07:22:25

CD sells a complete kit that my PO used on my boat for putting the antenna at the top of the mast. It comes with everything that you need. If you drop the mast often you might want to change the through the deck clam fitting to a deck connector fitting to make it a little faster to disconnect but I don't drop the mast often so I like the clam fitting and the connector inside the boat protected from the elements and the inevitable foot kicking.
https://www.catalinadirect.com/index.cfm/product/630_32/vhf-antenna-kit-cp-22-c-22-c-25-c-250--cp-26.cfm
The antenna is the round thing. the whip is removed.

Inside the cabin in the head.

The antenna they give you

Thru deck clam fitting they give you

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Sailynn
Navigator

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USA
178 Posts

Response Posted - 12/13/2018 : 15:32:21

use handheld radio on municipal lake. wired for antenna but never used it and removed radio.

Lynn Buchanan
1988 C25 SR/WK #5777
Sailynn
Nevada City, CA

islander
Master Marine Consultant

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USA
4012 Posts

Response Posted - 12/13/2018 : 16:51:46

Lynn, I just noticed that our boats are only 8 numbers apart. Funny that yours ended up in California and mine in LI NY.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

kwalsh
1st Mate

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USA
33 Posts

Response Posted - 12/13/2018 : 17:46:57

Hi All,
While we were re-rigging our boat earlier this sailing season, we replaced the wiring harness and antenna cable inside the mast, replaced all components at the mast head. We purchased the kit from CD, but did not use the clam fitting. I wish we thought of keeping the connection inside the cabin as Scott did. Another project on the To-Do List.
New radio and antenna works fine!

Kevin Walsh
Segelboot
1984 C25, TR/SK
Sail No. 4433

Voyager
Master Marine Consultant

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USA
5320 Posts

Response Posted - 12/13/2018 : 21:23:59

For salt water coastal cruising the difference between a rail-mounted antenna and a mast top-mounted antenna are like night and day. Because VHF is largely a line of sight signal type, VHF range is a strong function of height, not so much a function of power. If you work out the geometry around the height versus the distance to the e apparent horizon, the distance is about 3 miles from rail height, while distance to the horizon from an antenna mounted at 33 feet is more like 15 miles.
I do a radio check on ch 24 to a harbor 3 towns away, or about 12 miles as the crow flies. Boat US makes a short recording of your transmission and plays it back embedded in a message. When I use my 5W handheld the Boat US repeat is scratchy and often unintelligible, while my mast top VHF provides a crystal clear signal on the radio check.
There is no doubt that mounting on the mast top provides a signal with a much longer throw

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Erik Cornelison
Navigator

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USA
194 Posts

Response Posted - 12/15/2018 : 12:49:47

The Catalina Direct kit looks fine, except for the clamshell. I prefer a more professional solution.

I would prefer a plug on the cabin top for the antenna cable, anyone recommend one? Or company catalog?

I step my mast a few times a year and the boat will be sailing saltwater sometimes in the future.

Erik Cornelison
6th Generation Professional Sailor, First Gen Submarine Sailor.
1986 Standard Rig SW. #5234

Lee Panza
Captain

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USA
465 Posts

Response Posted - 12/15/2018 : 23:42:04

Erik:

I, too, wanted a weather-tight cable disconnect on the exterior for when I drop my mast. I figured that the compression gland in the through-deck fitting like in the Catalina kit would eventually lose its resiliency and start leaking after repeated openings. I was able to find a nice deck-mounted fitting for the cable coming out of the cabin top and a weather-tight terminal fitting for the cable coming down from my mast-head antenna.

Unfortunately, I have not been able to locate a deck-mounted fitting for the type of cable that comes in the Catalina Direct kit. The Catalina Direct kit apparently uses RG8X cable (they sell coils of cable of that type on the same page). While there are better types of cable for superior signal conductivity, such as the RG8U/RG213 cable that I had decided to use, RG8X is relatively slender (0.242 in.) so it is relatively easy to run. However, I can�t find a suitable deck mount connector for that size cable, along with a suitable female connector for the cable coming down from above. Therefore, I am recommending a pair of weather-tight terminal fittings just above the cabin top with the Catalina Direct through-deck fitting where the lower cable penetrates the deck.

For a weather-tight joint you should want N Type connectors. You should want clamping type connectors, rather than crimp type, which describes how they are fastened to the cable. Clamping type connectors use a compression gasket around the cable, and you tighten down on it using an ordinary wrench. The crimp type is not weather tight, and water will flow down the cable jacket into the connector. It also requires a crimping tool of the right size.

The best I could find for you is a male-female set made by RF Industries and sold by several distributors. Google �RFI RFN-1004� and �RFI RFN-1026.� You would still use the through-deck fitting around the cable below this joint, with just a short length of cable above it, but the disconnect is outside so you never remove the top portion of the through-deck fitting: you simply unscrew the two connectors to separate them.

N Type connectors were designed to be weather tight when assembled and connected together. For an added measure of security, however, I�d wrap some self-amalgamating silicone tape (�Rescue Tape� or similar) around the neck of the upper connector where the cable enters it. To be even more secure, wrap some tape down around the entire assembly and replace it each time you disconnect it (the tape�s cheap enough).

I can�t attest to the quality of RFI fittings (I used Amphenol fittings) but this is essentially how I did my cable disconnect (except I used a deck-mounted fitting for the lower end), and it has been trouble-free for years. When I separate the fittings and examine their interiors they have remained in like-new condition.

I hope this is helpful.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

islander
Master Marine Consultant

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USA
4012 Posts

Response Posted - 12/16/2018 : 08:54:59

Like Lee, I did not have much luck in finding a VHS deck connector that connects like an electrical connector and possibly there isn't one unless someone else can show us. This doesn't mean you can't make one up. So here is an idea. You could use this Ancor Coax Bulkhead / Deck Feed Through. You could add two fender washers drilled out to size, One outside and one inside along with bedding compound or caulk. Drill the hole in the deck, Chamfer the hole, Caulk the hole, Put the Ancor fitting with one washer down into the hole, Add washer and nut on the interior and tighten.https://www.defender.com/product.jsp?id=3415414

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Stinkpotter
Master Marine Consultant

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Djibouti
9047 Posts

Response Posted - 12/16/2018 : 10:32:16

I like Scott's approach--check the overall thickness of the reinforced and cored cabin-top at the mast-step. That Defender connector is long enough for 1-3/8" max--maybe just 1-1/4 including washers on both sides. A longer one may be out there somewhere. And after everything is nicely bedded, I'd add a rubber washer on top of the outside collar-nut to seal the connection when you tighten down the male coax connector. And I'd find a rubber cap at the hardware store to put on the deck connector when the mast is down.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Edited by - Stinkpotter on 12/16/2018 20:28:25

islander
Master Marine Consultant

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USA
4012 Posts

Response Posted - 12/16/2018 : 13:39:37

I don't remember the deck being that thick that this fitting wouldn't work Maybe somewhere between 1/2" to 1"

quote:
And I'd find a rubber cap at the hardware store to put on the deck connector when the mast is down.

5/8" chair leg protectors should work.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

islander
Master Marine Consultant

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USA
4012 Posts

Response Posted - 12/17/2018 : 11:18:46

Good find on that kit.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Erik Cornelison
Navigator

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USA
194 Posts

Response Posted - 12/17/2018 : 13:56:29

Wow thanks guys, you bring a lot of knowledge here...looks like I�ll be ordering some parts this spring for the new install.

Erik Cornelison
6th Generation Professional Sailor, First Gen Submarine Sailor.
1986 Standard Rig SW. #5234

Voyager
Master Marine Consultant

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USA
5320 Posts

Response Posted - 12/18/2018 : 16:37:21

Bjoye,
For the non-electrical engineers in the group I think it might be helpful if we learned a little about what the heck a VSWR (pronounced VIZ-wer) is. It literally means a Voltage Standing Wave Ratio. Still gobbledygook.

It�s a figure of merit that tells RF engineers how much power they are delivering to an antenna. Simply put, the more power you can drive into the antenna, the more powerful your transmitted signal is.

A bad reading tells you that because of a defect in the antenna and cabling, you�re wasting power and not getting your money�s worth.

Poor VSWR often comes from bad cable, bad connections, mismatched components. Some cables and connectors are rated for 75 Ohms like cable TV, but VHF should be 50 Ohms rated.

Also, any time you have a bunch of connectors in the system, this increases the likelihood of corrosion and less-than-ideal impedance matching. As in most technical matters, the KISS rule is best: keep it simple Simon.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Edited by - Voyager on 12/18/2018 16:42:22

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