help with vhf antenna wire

Surubi

Newbie
Nov 24, 2008
80
0
Torrance, CA
Name
Daniel
Boat
21' Cristaliner
Hi,
I have a vhf antenna with the cable cut. I would like to buy a longer live of cable and extend the one it has.
Any idea of the type of fitting that I should buy to join both coaxial cables together?
Thanks
 
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ConSeaMate

Legend in my own mind
Sep 6, 2005
2,686
286
65
Escondido
Name
Buster Brown
Boat
28' Silverton "ConSeaMate"
Hi,
I have a vhf antenna with the cable cut. I would like to buy a longer live of cable and extend the one it has.
Any idea of the type of fitting that I should buy to join both coaxial cables together?
Thanks

Go to West Marine they have the connectors there for about $10......they are gold plated!....
 
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Texlee

Member
Jun 3, 2012
891
315
Vernon, Texas, USA
Name
Alben Lee
Boat
Excel
Call sign AE5RG. You need 2 each PL259 connectors and a barrel connector.
If you havent ever put PL259's on, you need to have someone do it for you.
Its real easy to short the PL259 out.
 
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ConSeaMate

Legend in my own mind
Sep 6, 2005
2,686
286
65
Escondido
Name
Buster Brown
Boat
28' Silverton "ConSeaMate"
[h=1]Coaxial Cable[/h]
Coaxial-Cable-1.jpg

Coaxial cable (coax) is designed to transfer your radio transmitter’s energy to your antenna with as little loss as possible. It is precisely made, with the correct impedance for VHF installations.
We offer three kinds of 50-ohm coax cable for VHF radio installations: RG-58U, RG-8X, and RG-213, the mil-spec replacement for RG-8U. Use the largest coax you can fit to reduce signal loss. Here is the reason: Almost all VHF radios start with about 25 watts of transmit power. As soon as the signal starts down the coax cable, it begins to lose strength. This loss is measured in dB. High gain antennas cannot recover this lost energy, but they can focus the remaining energy across the water so you come through with as much punch as possible.
Bigger coax reduces signal losses between the radio and the antenna, which increases power at the antenna. This chart shows the effect of using different sizes of coax:
Coax Size vs. Signal Loss
Cable:20'40'60'80'100'
RG-58U-1.2dB-2.4dB-3.6dB-4.9dB-6.1dB
RG-8X-0.9dB-1.8dB-2.7dB-3.6dB-4.5dB
RG-213-0.5dB-1.0dB-1.6dB-2.1dB-2.7dB
We strongly recommend that you use Ancor coax cable unless your antenna is supplied with cable. Ancor cable has a very tightly woven shield braid and uses tinned wire for greater corrosion resistance.
One of the most common ways to negatively impact your radio’s performance is with a poor splice to your antenna cable. Splices made without the correct connectors can reduce your transmit power by a factor of ten or more. When it is necessary to splice a coax cable, like at the base of a mast, use PL-259 connectors and a PL-258 double female connector. This method will reduce losses compared to simply soldering or crimping the conductors together.

One drawback of connectors is that they can allow water to get into the cable. Water tends to “wick” inside the braided shield on the cable, which quickly corrodes the copper into a green crust. You must protect all coax connections from water intrusion, especially in the bilge area, masthead, or where exposed to water.
For connections that are open to the elements, we recommend Ancor heat shrink tubing, after coating the connection with silicone grease. Many turns of waterproof tape is an acceptable, but less desirable, alternative.
[h=2]Installing a PL259 connector[/h] The most difficult part of a marine antenna installation may be attaching the PL-259 connector. This Shakespeare video explains how to do it in three different ways: no-solder compression, the traditional solder method, and the Centerpin® easy way.
 
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flyinverted

If it floats, flys or fornicates, RENT IT.
  • Apr 24, 2012
    411
    155
    Fullerton, CA
    Name
    Steve
    Boat
    Trojan F32
    "As soon as the signal starts down the coax cable, it begins to lose strength. This loss is measured in dB. High gain antennas cannot recover this lost energy, but they can focus the remaining energy across the water so you come through with as much punch as possible."

    The punch comes from the microphone and other gain settings in the radio, not the the ERP. You can put out 1000 watts and have horrible audio with a poor microphone and poor radio.

    RG213 at 150mhz has about 2.5dB loss over 100 feet. With a stock Shakespeare 8 foot antenna and 15 foot antenna run with 6dB gain assuming a < 1.5:1 match you'll still have plenty of gain over the coax loss and about 60 watts of ERP from the 25 watt radio.

    I would not use any extensions, or splices. Just replace the feedline from the radio to the antenna.

    Your radio system may be your only link between you and a rescuer. Your safety isn't worth going cheap here.



     
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    daveiam

    Newbie
    Nov 17, 2013
    2
    0
    Granite Bay, CA
    Name
    David Brown
    Boat
    Special Ops
    I have a related question the I hope someone can answer: I am installing an 8-foot Shakespere antenna on my new boat for a VHF radio. I will have about 5-feet of extra cable. Can I cut the cable to size before attaching the connector?
     
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    invictus

    AVD
    May 26, 2006
    4,416
    2,002
    Orange County
    Name
    Jason
    Boat
    Tiara 2000 Cuddy
    Times two on sweating your connections, very easy to short, too much solder is a general cause.
     
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