How to splice VHF coaxial cable

Yana Murphy

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Jan 11, 1998, 3:00:00 AM1/11/98

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After restepping the mast on my Cal 2-27, I discovered that the VHF coaxial
cable is about 3' too short... to link up to its former connection. Is it ok
to splice in an extra length without losing any of the signal strength, etc.

And what's the best way to splice it?

I still need to remount half of the screw barrel (?) connector that I cut off
so I could feed the cablu through the mast step opening.

Thanks.

__________________Yana Murphy_________________________________

A day sailing on the San Francisco Bay
beats months of 'traditional' therapy.

ya...@yahoo.com
http://users.lanminds.com/~yana

James W. Hebert

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Jan 12, 1998, 3:00:00 AM1/12/98

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In article <34B99A57...@yahoo.com>, ya...@yahoo.com wrote:

>After restepping the mast on my Cal 2-27, I discovered that the VHF coaxial
>cable is about 3' too short... to link up to its former connection. Is it ok
>to splice in an extra length without losing any of the signal strength, etc.
>
>And what's the best way to splice it?
>
>I still need to remount half of the screw barrel (?) connector that I cut off
>so I could feed the cablu through the mast step opening.

The best approach to lengthening a coaxial cable is to
put a connector on the end and connect it to another
piece of cable.

I would not recommend trying to fashion a splice of the
cable without using connectors.

The simplest way is probably to put a "male" connector
on the end of the cable, and use a "barrel" connector
to connect to another short piece of cable.

There are cable-end "female" connectors available, but
you might have more trouble finding and installing them
than using the method I described above.

If you are using the "UHF" or SO-239 series connectors,
be sure to finish the installation with a good wrapping
of electrical tape to provide some weather proofing.

I recommend SCOTCH-33-plus electrical tape.

You will also need some soldering equipment to install the
connectors.

Good luck,

--jim

JBChalais

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Jan 12, 1998, 3:00:00 AM1/12/98

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Yana Murphy wrote:
>
> After restepping the mast on my Cal 2-27, I discovered that the VHF coaxial
> cable is about 3' too short... to link up to its former connection. Is it ok
> to splice in an extra length without losing any of the signal strength, etc.
>
> And what's the best way to splice it?
>
> I still need to remount half of the screw barrel (?) connector that I cut off
> so I could feed the cablu through the mast step opening.
>

> Thanks.
>
> __________________Yana Murphy_________________________________
>
> A day sailing on the San Francisco Bay
> beats months of 'traditional' therapy.
>
> ya...@yahoo.com
> http://users.lanminds.com/~yana

Yana, Just replace the co-ax. While your at it use the marine RG8u
instead of (I bet) the stuff that's in there now. Get enough to run all
the way from the mast head to the radio. No splices if you can help it.
Should produce a good strong signal.

Jack

twill

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Jan 12, 1998, 3:00:00 AM1/12/98

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Yana Murphy wrote:
>
> After restepping the mast on my Cal 2-27, I discovered that the VHF coaxial
> cable is about 3' too short... to link up to its former connection. Is it ok
> to splice in an extra length without losing any of the signal strength, etc.
>
> And what's the best way to splice it?
>
> I still need to remount half of the screw barrel (?) connector that I cut off
> so I could feed the cablu through the mast step opening.
>
> Thanks.
>
> __________________Yana Murphy_________________________________
>
> A day sailing on the San Francisco Bay
> beats months of 'traditional' therapy.
>
> ya...@yahoo.com
> http://users.lanminds.com/~yana

I wouldn't try to splice it, in the normal sense of "splicing" by simply
soldering coax cable to coax cable. Not sure what you would do to the
impedance matching (to drop a techie phrase ;-). Just get the three
feet of coax (I would match teh type of coax exactly to whatever you
have now, just to be safe) and the necessary connectors. Connectors
have very low losses. Get them from your friendly marine supply place.
Twill

Terry Spragg

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Jan 13, 1998, 3:00:00 AM1/13/98

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As Jack says,you should not splice coax. But, for emergencies, you might give
it a try for training and confidence sake. I have done this, and it works.

Strip the outer shield back an inch on each side. try not to damage the outer
insulator or shielding, cut around the outside, slide the tubing off, slit
lenghwise carefully if neccessary, unbraid the woven shields, seperate into
three parts, twist each part to make pigtails. Strip the centre conductor
back 7/8", each side, scrape clean with a knife blade. perform a western
union splice on the centre conductor, wrapping both pieces around the opposite
part, keeping it all close and neat, wrap the ends down snug, cutting off the
last 1/4" with your swiss army scissors. Solder if you've got it. (remember,
this is an emergency, right?) If you solder, ensure there is no sideways
stress on the wire, use a third hand, don't overheat. You must 'sweat' the
solder into the stranded wire, a gob will not do, too much heat will produce a
short inside the coax, possibly killing your transmitter.

Soldering done with plumber's solder (acid flux) will not last. Nor will
rosin core solder either for that matter, not in salt air... If you don't have
the right solder, don't try to solder the wire, it won't help.
Use a piece of the outer conductor, slit lengthwise, to insulate the spliced
center wire. cover with two neat turns of tape cut to the right width, any
kind, electrical preferred. Line the wires up, twist the 6 shield pigtails
together into 3 , so that they stick out the sides. Solder if you got it, with
the same regard for melted insulation (I would tend not to, unless I really
needed to get a long time out of this, ie jury rigged sailing home for a
month.). Fold them down flat, seal water out with tape, reinforce with tape
for physical protection, make your mayday call. It's rough, I know, but it
will do in a pinch. You will always lose some signal strength with every
connection. This splice, if done really neatly, can produce good results.

The best place for a connector, other than the ONE at the masthead, is inside
the boat, out of the weather. A double female adapter will enable you to
extend as far as you need to go inside the cabin. It is better to have a
single, unspliced length end to end. You will lose about half your signal for
every 3 connector joints in line, if all is well otherwise. A female cable
end saves one connector pair, but they are scarce, and more difficult to
install. These days, it is possible to get screw on cable connectors, but the
directions included are not good, and you need a knack to get them to work,
and usually exactly the right brand of coax.

Cough up, hire a tech, do it right, with crimped on ends, your life could hang
on this wire.

-Terry

Steve Brook

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Jan 14, 1998, 3:00:00 AM1/14/98

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Yana

There is no way to splice 3' more cable on without any loss. Two possible
suggestions.

1. Reterminate the cable 3' short with a BNC plug, have a new bit of cable
made up for the remaining length and put a BNC to BNC connector in series
with it and connect it back to the old cable. You will have a loss using
this method.

2. Use the old cable and pull a new cable through the mast with it. No loss
but a new bit a cable.

Use new connectors for both methods, it avoids having any extra losses with
badly terminated connectors

If only things were easy.

Steve

Yana Murphy wrote in message <34B99A57...@yahoo.com>...

Geoff Blake

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Jan 14, 1998, 3:00:00 AM1/14/98

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Steve Brook (broo...@globalnet.co.uk) wrote:
: Yana

: There is no way to splice 3' more cable on without any loss. Two possible
: suggestions.

Correct, although a properly installed BNC (or better still TNC) connecter
will have a negligible loss at VHF frequencies...

: 1. Reterminate the cable 3' short with a BNC plug, have a new bit of cable

: made up for the remaining length and put a BNC to BNC connector in series
: with it and connect it back to the old cable. You will have a loss using
: this method.

Yes, but use a BNC (TNC) female on the end of the cable from the mast.
Unless you are (and feel) very competent, get a skilled technician to put it
on. When reconnected, make the joint water/moisture proof.

: 2. Use the old cable and pull a new cable through the mast with it. No loss

: but a new bit a cable.

The best way. If you currently use RG58 cable, and if you have space,
replace it with RG8 or RG214 cable, less lossy.

: Use new connectors for both methods, it avoids having any extra losses with
: badly terminated connectors

Again if you don't feel competent, get a techie to fit the plugs. He will
probably use crimp connectors, which have less dissimilar metal junctions.

: If only things were easy.

:-)

Geoff

: Yana Murphy wrote in message <34B99A57...@yahoo.com>...

: >After restepping the mast on my Cal 2-27, I discovered that the VHF coaxial
: >cable is about 3' too short... to link up to its former connection. Is it
: ok
: >to splice in an extra length without losing any of the signal strength,
: etc.
: >
: >And what's the best way to splice it?
: >
: >I still need to remount half of the screw barrel (?) connector that I cut
: off
: >so I could feed the cablu through the mast step opening.
: >
: >Thanks.
: >
: >
: >__________________Yana Murphy_________________________________
: >
: >
: >A day sailing on the San Francisco Bay
: >beats months of 'traditional' therapy.
: >
: >ya...@yahoo.com
: >http://users.lanminds.com/~yana

--
--
Geoff Blake ge...@palaemon.demon.co.uk linux 2.0.31
Chelmsford g8...@g8gnz.ampr.org i586
Intel create faster processors - Microsoft create slower processes

Jralbert

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Jan 16, 1998, 3:00:00 AM1/16/98

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there's yet another reason for not splicing in an additional length of cable
with or without connectors, even though inserting an extra length with
connectors potentially won't induce significant loss. The more connectors you
add, the more points of failure you introduce. The reply you have received
suggesting a whole new length of cable is the best advice, You can use the
existing line as a "messenger" to pull the new (and as he wrote, improved) low
loss cable into place. One uninterrupted strand is better in any wiring
project. That's the way the engineers at my TV station do it.. eg when
critical equipment has to be moved a few feet and the cable won't stretch, they
replace it with one of the proper length even if it means spending more money.

Your boat communications comes under the critical category.

good luck

In article <34BAFD...@ibm.net>, twill <jus...@ibm.net> writes:

>
> After restepping the mast on my Cal 2-27, I discovered that the VHF
>coaxial
> cable is about 3' too short... to link up to its former connection.
>Is it ok
> to splice in an extra length without losing any of the signal
>strength, etc.
>

Joel Albert
Potomac, MD
((jral...@aol.com))