Hookup Question---Gps/Vhf at 2 stations
 

I am thinking of buying a Garmin 76csx Gps and an Icom M422 VHF. The
Icom will transfer NEMA data to and from the gps for position display
on my or another boat's gps. Use will be on a sail boat and I'd like
to be able to use the gps at both the helm and in the cabin where the
vhf radio is.

Question is, can I just common the NEMA IN/OUT data cables at both
stations between the gps and vhf? That is, simply plug the gps into
whichever location I want to use it at, by hooking the data cables
together in parallel. Of course only the 1 gps would be hooked to the
one vhf radio at whichever gps station. My concern is impedence or
stray signals possibly from the unterminated data cable.

Wold be using these data cables from Garmin. Run would only be about
10 feet between the cabin and helm station.

http://shop.garmin.com/accessory.jsp...0%2D10082%2D00

Hookup Question---Gps/Vhf at 2 stations
 

Chandrella wrote in
:

Question is, can I just common the NEMA IN/OUT data cables at both
stations between the gps and vhf? That is, simply plug the gps into
whichever location I want to use it at, by hooking the data cables
together in parallel. Of course only the 1 gps would be hooked to the
one vhf radio at whichever gps station. My concern is impedence or
stray signals possibly from the unterminated data cable.

Wold be using these data cables from Garmin. Run would only be about
10 feet between the cabin and helm station.


NO! Never connect NMEA out and in together on any device. NMEA is a
queer beast. There can be only ONE talker on a circuit...one device
sending out data to up to 16 listener devices. So, GPS NMEA OUT goes to
VHF NMEA IN on one pair of wires and GPS NMEA IN goes to VHF NMEA OUT on
a separate pair of wires. (Actually NMEA - is most always hooked to
ground by some stupid company or other, but use a wire pair, anyways.

I use FOIL SHIELDED cable for all NMEA data cables wherever possible. It
keeps the radiation down that tears up the radios. Ground the shield to
the RADIO ground ONLY. It's called a Faraday Shield because Michael
Faraday invented it long ago. Leave the shield connected to nothing and
insulated from everything on the GPS end of the cable. Do not use the
shield for connections to NMEA DATA - leads, which makes it just another
noise antenna.

Good cable to use for this installation is available at computer shops.
It's call CAT-5 shielded cable used for Ethernet networking. It has more
than 4 conductors. Just cut off the ones you're not using short, NOT
wrapped up around the outside to form another noise antenna from inside
the shielding, please. Keep all those unshielded wires on the GPS and
radio as short as is practical to reduce their radiation.



Larry
--
VIRUS ALERT! VISTA has been released!
NOONE will be spared!

Hookup Question---Gps/Vhf at 2 stations
 

Chandrella,

You are running so many things together there that it is difficult to
keep track.

Are you saying:

You will have one (1) GPS that you hope to use in two (2) locations?

And you hope to do this by have two identically wired connectors, one at
each location?

You hope that this will work effectively with your Icom?

If this is correct, yes, I do this all the time. In fact mine connects
to a data buss in any of three places, but it does have to be connected
to one for the autohelm to steer on wind because I pass that through the
Garmin (this one is a 48).

Matt Colie
Lifelong Waterman, Licensed Mariner and Pathological Sailor


Chandrella wrote:
I am thinking of buying a Garmin 76csx Gps and an Icom M422 VHF. The
Icom will transfer NEMA data to and from the gps for position display
on my or another boat's gps. Use will be on a sail boat and I'd like
to be able to use the gps at both the helm and in the cabin where the
vhf radio is.

Question is, can I just common the NEMA IN/OUT data cables at both
stations between the gps and vhf? That is, simply plug the gps into
whichever location I want to use it at, by hooking the data cables
together in parallel. Of course only the 1 gps would be hooked to the
one vhf radio at whichever gps station. My concern is impedence or
stray signals possibly from the unterminated data cable.

Wold be using these data cables from Garmin. Run would only be about
10 feet between the cabin and helm station.

http://shop.garmin.com/accessory.jsp...0%2D10082%2D00

Hookup Question---Gps/Vhf at 2 stations
 

Yes, one gps, 2 locations. If I were just hooking up one location it
would simply be VHF in from gps out and VHF out to gps in (with their
respective grounds/shields.

Since I also want a 2nd gps location I was planing to simply mount
the gps connector at the 2nd location, run the cable, and connect to
the VHF as I did with the first connection.

It appears this is what you do Matt, so I'll quit worrying about any
stray signal being picked up in the connector and cable that's not in
use.

On Sat, 10 Feb 2007 18:57:00 -0500, Matt Colie
wrote:

Chandrella,

You are running so many things together there that it is difficult to
keep track.

Are you saying:

You will have one (1) GPS that you hope to use in two (2) locations?

And you hope to do this by have two identically wired connectors, one at
each location?

You hope that this will work effectively with your Icom?

If this is correct, yes, I do this all the time. In fact mine connects
to a data buss in any of three places, but it does have to be connected
to one for the autohelm to steer on wind because I pass that through the
Garmin (this one is a 48).

Matt Colie
Lifelong Waterman, Licensed Mariner and Pathological Sailor


Chandrella wrote:
I am thinking of buying a Garmin 76csx Gps and an Icom M422 VHF. The
Icom will transfer NEMA data to and from the gps for position display
on my or another boat's gps. Use will be on a sail boat and I'd like
to be able to use the gps at both the helm and in the cabin where the
vhf radio is.

Question is, can I just common the NEMA IN/OUT data cables at both
stations between the gps and vhf? That is, simply plug the gps into
whichever location I want to use it at, by hooking the data cables
together in parallel. Of course only the 1 gps would be hooked to the
one vhf radio at whichever gps station. My concern is impedence or
stray signals possibly from the unterminated data cable.

Wold be using these data cables from Garmin. Run would only be about
10 feet between the cabin and helm station.

http://shop.garmin.com/accessory.jsp...0%2D10082%2D00

Hookup Question---Gps/Vhf at 2 stations
 

Ok Chandrella,
What you are planning will work out just fine. Do not worry about the
unused connector except to prevent seawater from getting in.
Fair Wind and Smooth Sea
Matt Colie

Chandrella wrote:
Yes, one gps, 2 locations. If I were just hooking up one location it
would simply be VHF in from gps out and VHF out to gps in (with their
respective grounds/shields.

Since I also want a 2nd gps location I was planing to simply mount
the gps connector at the 2nd location, run the cable, and connect to
the VHF as I did with the first connection.

It appears this is what you do Matt, so I'll quit worrying about any
stray signal being picked up in the connector and cable that's not in
use.

On Sat, 10 Feb 2007 18:57:00 -0500, Matt Colie
wrote:

Chandrella,

You are running so many things together there that it is difficult to
keep track.

Are you saying:

You will have one (1) GPS that you hope to use in two (2) locations?

And you hope to do this by have two identically wired connectors, one at
each location?

You hope that this will work effectively with your Icom?

If this is correct, yes, I do this all the time. In fact mine connects
to a data buss in any of three places, but it does have to be connected
to one for the autohelm to steer on wind because I pass that through the
Garmin (this one is a 48).

Matt Colie
Lifelong Waterman, Licensed Mariner and Pathological Sailor


Chandrella wrote:
I am thinking of buying a Garmin 76csx Gps and an Icom M422 VHF. The
Icom will transfer NEMA data to and from the gps for position display
on my or another boat's gps. Use will be on a sail boat and I'd like
to be able to use the gps at both the helm and in the cabin where the
vhf radio is.

Question is, can I just common the NEMA IN/OUT data cables at both
stations between the gps and vhf? That is, simply plug the gps into
whichever location I want to use it at, by hooking the data cables
together in parallel. Of course only the 1 gps would be hooked to the
one vhf radio at whichever gps station. My concern is impedence or
stray signals possibly from the unterminated data cable.

Wold be using these data cables from Garmin. Run would only be about
10 feet between the cabin and helm station.

http://shop.garmin.com/accessory.jsp...0%2D10082%2D00


--
target of diversity
victim of affirmative action
refugee from the war on poverty
minimized by political correctness

Hookup Question---Gps/Vhf at 2 stations
 

"Chandrella" wrote in message
...
I am thinking of buying a Garmin 76csx Gps and an Icom M422 VHF. The
Icom will transfer NEMA data to and from the gps for position display
on my or another boat's gps. Use will be on a sail boat and I'd like
to be able to use the gps at both the helm and in the cabin where the
vhf radio is.

Question is, can I just common the NEMA IN/OUT data cables at both
stations between the gps and vhf? That is, simply plug the gps into
whichever location I want to use it at, by hooking the data cables
together in parallel. Of course only the 1 gps would be hooked to the
one vhf radio at whichever gps station. My concern is impedence or
stray signals possibly from the unterminated data cable.

Wold be using these data cables from Garmin. Run would only be about
10 feet between the cabin and helm station.


Should work great. NEMA "out" can usually send data to more than one
device, but of course you don't want more than one device transmitting on
one set of wires without "Data combiners" or equivalent.
Old Chief Lynn