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antenna coupler question

R

RB

Jan 1, 1970
0
The Eagle ELC-1 and Lowrance LC-1 loran antenna coupler modules each have a
4 pin plug at the end of the long pigtail cable.

Their pinout for the 4 pin plug is:

1 ground
2 XMIT
3 12vdc+
4 recv

Ground I understand. 12vdc+ I understand. RECV I understand. What I
don't understand is XMIT. What function does this wire play ? What would
be transmitted from a loran set?

I assume pins 3 and 4 would be jumped together and go to the center of the
chassis bnc fitting on most loran sets. Pin 1 would be hooked to chassis
ground. All this sound right?

That leaves pin 2. Does it just float?
 
P

Peter Bennett

Jan 1, 1970
0
The Eagle ELC-1 and Lowrance LC-1 loran antenna coupler modules each have a
4 pin plug at the end of the long pigtail cable.

Their pinout for the 4 pin plug is:

1 ground
2 XMIT
3 12vdc+
4 recv

Ground I understand. 12vdc+ I understand. RECV I understand. What I
don't understand is XMIT. What function does this wire play ? What would
be transmitted from a loran set?

I can't find any evidence of these products on Lowrance's or Eagle's
web sites...

I wonder if these are in fact Loran-C receivers rather than just
antenna couplers (like the GPS antenna/receiver modules)?

If they were just antenna couplers, I would expect them to just have a
coax cable, not a multi-conductor cable.

If they are receiver/antenna modules, then I'd expect NMEA-0183 data
from either pin 2 or 4 ("receive" and "transmit" can be confusing at
times...) when 12 volt power is applied between pins 3 and 1. The
navigation computer in the display unit could send configuration data
to the receiver ("use chain 5990X and Y" type of commands), while the
LC-1 outputs current position, speed and direction of travel.

It may be worthwhile contacting Lowrance or Eagle directly to see if
anyone there can find anything on these units.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
 
R

RB

Jan 1, 1970
0
With what you guys have said, I'm beginning to think maybe they're rcvr/ant
modules. Haven't encountered those before. What would they be used with if
there's a receiver also in the coupler module?

Any way to use the coupler part as a conventional coupler? Maybe pins 3 and
4 to a conventional loran set?
 
P

Peter Bennett

Jan 1, 1970
0
With what you guys have said, I'm beginning to think maybe they're rcvr/ant
modules. Haven't encountered those before. What would they be used with if
there's a receiver also in the coupler module?

Any way to use the coupler part as a conventional coupler? Maybe pins 3 and
4 to a conventional loran set?

No - if it is a receiver/antenna unit, the Loran-C RF won't be
available on that cable - only serial data (probably NMEA-0183). The
display unit it was intended to be used with was progbably just a
navigation computer that would display position, and deal with
waypoints, routes, etc.
 
P

Peter Bennett

Jan 1, 1970
0
Of course, if you have only one antenna, to be used for a navigation
and other reciever and for a transmitter on the same band, you would
not want tx power sent to the rx.

The presence of a tx key line in the cable is a dead givaway. When the
tx is keyed, the loran is disconnected by a sharing relay.

This is old tech, right?

Terry K

Since Loran-C operates on 100 KHz, it is highly unlikely that the
antenna would be shared with any transmitter.




--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
 
R

RB

Jan 1, 1970
0
Many thanks. Just got an education. I had no idea there are modules like
that with the loran receiver inside the module. Good to know and glad I
asked.
 
L

Lynn Coffelt

Jan 1, 1970
0
Terry K said:
Unless the radiating element was decoupled from matching for 100khz and
connected to matching capable of transmit at some other freq? Thence
the need for a tx line in the antenna cable.

I don't claim to know every option available on these things. I have a
Furuno LC-80 Loran c in the basement, it came uninstalled with a boat,
but I never needed to use it nor had it connected for any reason. It
has only 3 pins in the connector, and a big base loading coil.
A relay in there might enable use of the 8 foot glass whip at other
freqs.

Terry K

Well, tx and rx lines are necessary because the antenna module must get
programming data from the display unit. In other words, it must receive (rx)
data from the display, asking for the unit to tune to the proper GRI and
slaves for the area in which it is being used. THEN, the LORAN received (and
decoded?) data must be transmitted (tx) to the displaying unit. The tx and
rx lines give this serial port connection the steering and coordination
necessary to get the job done.
Old Chief Lynn
 
Y

You

Jan 1, 1970
0
Terry K said:
I have a
Furuno LC-80 Loran c in the basement, it came uninstalled with a boat,
but I never needed to use it nor had it connected for any reason. It
has only 3 pins in the connector, and a big base loading coil.
A relay in there might enable use of the 8 foot glass whip at other
freqs.

Terry K

Inside that "big base loading coil" is an active Preamp and impedance
coupling system that is designed to match an 8' CB Whip antenna
(Shakespear 10-4) at Loran C operating frequency of 100Khz. The "Three
Wires" are +DC Power, Ground and RF signal.
 
L

Lynn Coffelt

Jan 1, 1970
0
Lynn Coffelt said:
Well, tx and rx lines are necessary because the antenna module must get
programming data from the display unit. In other words, it must receive (rx)
data from the display, asking for the unit to tune to the proper GRI and
slaves for the area in which it is being used. THEN, the LORAN received (and
decoded?) data must be transmitted (tx) to the displaying unit. The tx and
rx lines give this serial port connection the steering and coordination
necessary to get the job done.
Old Chief Lynn
I started to warn of bad information in my response to the "antenna
coupler question", but after "Googling" for a few minutes I see on the
Lowrance site, in the company history, there is this sentence:
"In 1988, the Company introduced the first fully waterproof SONAR/Loran-C
combination units featuring all Loran-C circuitry and software contained
solely in the antenna coupler module."
So, as I recall (pretty thin stuff to work with), this coupler was
really a departure from all the other manufacturer's use of the coupler as
merely a tuned, very selective, 100khz amplifier, for use with an 8' whip.
(ok, a couple used a shorter, stainless steel whip)
I have actually seen one of these LMS-300/LC-1 combination work.....
not like a Furuno, of course, but still did function.
I stick to the quasi serial cable story.
Old Chief Lynn
 
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