Running an antenna wire
 

Hi all

and thanks for the help in the past

Does any know how, or if you can cut and splice the antenna from a
GPS?

THe GPS antenna on my boat is shot and needs to be replaced.

THe issue is I cannot tale the radar arch apart to run the new wire
without cutting it.

So...

Any tricks of the trade to cutting a GPS antenna cable?

THanks
MH

On Wed, 05 Jan 2005 16:10:16 -0500, g wrote:
Does any know how, or if you can cut and splice the antenna from a
GPS?

THe GPS antenna on my boat is shot and needs to be replaced.

THe issue is I cannot tale the radar arch apart to run the new wire
without cutting it.

Any tricks of the trade to cutting a GPS antenna cable?
==============================================
The usual strategy is to remove the factory connector from the end
going to the display unit, snake in the wire (sometimes using the old
cable to pull it), and finally re-installing the original connector.

g wrote:
Hi all

and thanks for the help in the past

Does any know how, or if you can cut and splice the antenna from a
GPS?

THe GPS antenna on my boat is shot and needs to be replaced.

THe issue is I cannot tale the radar arch apart to run the new wire
without cutting it.

So...

Any tricks of the trade to cutting a GPS antenna cable?

THanks
MH

It is usually low-loss TV coaxial cable, the same as VHS antenna cabling,
and you can join it using the VHS cable extenders available in most ship's
chandlers. (A cheaper join is by using network-joining cable extenders,
available from computer shops.)
Remove "nospam" from return address.

"Dennis Pogson" wrote in message
...
g wrote:
Hi all

and thanks for the help in the past

Does any know how, or if you can cut and splice the antenna from a
GPS?

THe GPS antenna on my boat is shot and needs to be replaced.

THe issue is I cannot tale the radar arch apart to run the new wire
without cutting it.

So...

Any tricks of the trade to cutting a GPS antenna cable?

THanks
MH

It is usually low-loss TV coaxial cable, the same as VHS antenna cabling,
and you can join it using the VHS cable extenders available in most ship's

I thought VHS = Video Home System (Video Recorder), you probably mean VHF.

chandlers. (A cheaper join is by using network-joining cable extenders,
available from computer shops.)
Remove "nospam" from return address.

Don't use TV coaxial cable, it's 75 ohm impedence.
VHF coax is 50 ohm impedence. So use 50 ohm impedence connectors, for a GPS,
BNC connectors will be ok.

BrianR wrote:
"Dennis Pogson" wrote in message
...
g wrote:
Hi all

and thanks for the help in the past

Does any know how, or if you can cut and splice the antenna from a
GPS?

THe GPS antenna on my boat is shot and needs to be replaced.

THe issue is I cannot tale the radar arch apart to run the new wire
without cutting it.

So...

Any tricks of the trade to cutting a GPS antenna cable?

THanks
MH

It is usually low-loss TV coaxial cable, the same as VHS antenna
cabling, and you can join it using the VHS cable extenders available
in most ship's

I thought VHS = Video Home System (Video Recorder), you probably mean
VHF.

chandlers. (A cheaper join is by using network-joining cable
extenders, available from computer shops.)
Remove "nospam" from return address.

Don't use TV coaxial cable, it's 75 ohm impedence.
VHF coax is 50 ohm impedence. So use 50 ohm impedence connectors, for
a GPS, BNC connectors will be ok.

Sorry about the misprint! VHF!
Remove "nospam" from return address.

g wrote:
Hi all

and thanks for the help in the past

Does any know how, or if you can cut and splice the antenna from a
GPS?

THe GPS antenna on my boat is shot and needs to be replaced.

THe issue is I cannot tale the radar arch apart to run the new wire
without cutting it.

So...

Any tricks of the trade to cutting a GPS antenna cable?


Check to see if it is a powered antenna, if it is there is a voltage on
the coax. You can usually check with a voltmeter at the connector. You
want to make sure the power is off before you mess with it.

Some options:

Cut the end fitting off the new coax and pull the new coax through the
arch with the old coax? Use BNC male and female connectors to rejoin
coax. There will be a very small loss in signal for adding the extra
connector but it will not be enough to worry about
if the connectors are crimped on right.

If you add inline connectors on a powered antenna, put insulation (heat
shrink, electrical tape, etc.) over because a voltage will be present on
the metal connectors and it may find a ground path.


The piece inside the arch will probably be okay and there may be some
extra length in the run. Can you pull some up, add new inline
connectors outside the arch?

Gurther to the last, sometimes the connection inside the antenna (if you
can get in there without destroying it) is a simple bared wire solder
joint. That would eliminate a connector if you can attach to the new
antenna there.

If you don't know how to do it and can find someone like a HAM or maybe
a marine electronics shop to install coaxial fitting for you, there is
some chance that it will be done right.

Good luck!

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)

"Jack Erbes" wrote in message
...
g wrote:
Hi all

and thanks for the help in the past

Does any know how, or if you can cut and splice the antenna from a
GPS?

THe GPS antenna on my boat is shot and needs to be replaced.

THe issue is I cannot tale the radar arch apart to run the new wire
without cutting it.

So...

Any tricks of the trade to cutting a GPS antenna cable?


Check to see if it is a powered antenna, if it is there is a voltage on
the coax. You can usually check with a voltmeter at the connector. You
want to make sure the power is off before you mess with it.

Some options:

Cut the end fitting off the new coax and pull the new coax through the
arch with the old coax? Use BNC male and female connectors to rejoin
coax. There will be a very small loss in signal for adding the extra
connector but it will not be enough to worry about
if the connectors are crimped on right.

If you add inline connectors on a powered antenna, put insulation (heat
shrink, electrical tape, etc.) over because a voltage will be present on
the metal connectors and it may find a ground path.


The piece inside the arch will probably be okay and there may be some
extra length in the run. Can you pull some up, add new inline
connectors outside the arch?

Gurther to the last, sometimes the connection inside the antenna (if you
can get in there without destroying it) is a simple bared wire solder
joint. That would eliminate a connector if you can attach to the new
antenna there.

If you don't know how to do it and can find someone like a HAM or maybe
a marine electronics shop to install coaxial fitting for you, there is
some chance that it will be done right.

Good luck!

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)

Not all GPS sensors are simple coax cable devices. There are active (voltage
on the coax from the display going to the senor) and passive (not voltage,
just an antenna at the sensor), and NMEA types, multiple wires for voltage
and signal. Also there are combinations of the above, for example an active
sensor with voltage on the coax which goes to a converter box usually hidden
somewhere near the helm, where it gets converted to NMEA and that is fed to
the display.
First verify all power is shut off to the antenna sensor, make your
temporary splice(s) at an inspection plate in the radar arch to the old
cable. Power up and see if everything works ok. If so, power down again,
shorten the cable from the new sensor after installing and make permanent
splice(s) to the old cable. Tape/weatherproof splices.
Also not all coax connectors are BNC, some are TNC, SMA, SLB, etc. For
splices, I use BNCs to the old cable and avoid having to change out odd
types at the equipment end.
73
Doug K7ABX