On Sat, 10 Jan 2004 13:13:04 -0800, "Steve" wrote:

I'm upgrading from my 1720 to a 1721 MKII radar.. I had this same model on
my last boat and missed many of it's features.
I knew the 1721 was capable of with a compass or gyro input but it was too
expensive to add back then.

However I did learn to get by without 'North UP' that I always had on
shipboard radar..(this was my first pleasure boat radar) So even now I'm
content to do without it Noth UP.

Not sure about that radar, but most of them will give you course up
display as soon as the GPS starts sending course information when the
boat starts moving. The only difference I see in a Raymarine RL70CRC
Plus is the boat is pointing in the right direction when it's standing
still.


Now I'm adding a Yeoman to my chart table and know that it can communicate
and plot on the 1721 radar, but when I get into the fine print of the
specifications I find that it requires that the radar have compass input
(heading sensor).

We, too, have a Yeoman. The only thing the yeoman requires is GPS RMC
statement. It doesn't care which way the boat is pointing as long as
the GPS tells it what our lat/long is for the reference point. We
used a Garmin handheld plugged into the Yeoman Sport XL on the last
boat and it worked fine. No heading sensor input is necessary that I
know of. The GPS feeds it course and speed as soon as you start
moving.

My captain left the Sport XL in the Atlanta summer sun and the glue
all melted that held it together. I took the electronics out of the
foam and stuck the plotting board to the bottom side of Lionheart's
chart table top mahogany lid that hinges up so you can get to the
charts inside. I used 5 pound/inch industrial-strength double-sided
tape from Home Depot and just made two strips of it longwise. The
Yeoman will read throught he 1/2"-thick mahogany table top, the whole
Map-Tech chart book's thickness and still has about 2" of freeboard
before the arrows start blinking above the chart book. Two fiddles
built into the lid give you a fixed surface to hold the chart book
stable for calibration and use. Works great and the only thing the
visitors see is the puck...(c;

I already have a Si Tex flux gate compass with NNEA 183 output and the
spec./hookup info for the 1721 indicates I can interface it with the Gyro
input..

AT Last: Here is my question. If my Furuno 1721 MKII has the heading sensor
hooked up and the Yeoman is proving a plot, does the radar have to be in
North UP display??

No, the Yeoman's only output to the radar would be any waypoints you
click up on the Yeoman's puck. The radar plot runs directly off the
GPS's constantly updated data.

But, you have some consideration concerning NMEA's crappy data system.
In any NMEA network, there can be ONLY ONE TALKER on a circuit! NMEA
has no data control lines. All the talkers (data senders like GPS
receivers, chart plotters, Yeomans, compass sensors.....all talkers,
will all transmit, continuously, at once, making a helluva data mess
to all the listeners hooked to the network.

So, you have some choices to make. If you want to use the Yeoman to
send waypoint data to the radar/chart plotter, you must connect its
output data to the radar's input data. But, if you do that, you can't
also connect the GPS data to the same port.....only one talker is
allowed.

So, the solution is a "multiplexer" like Meindert Sprang manufactures,
who is a regular contributor to this newsgroup. A multiplexer has
many inputs for all you talkers (NMEA data outputs). It stores all
this data in memory, then reads out this data to all the talkers on
the network IN TURN, not all at once, in a neat, orderly fashion.
These multiplexers also have a serial port so you can connect a
computer running software like The Cap'n or another charting/nav
software to process, display and digest all this data in a more
controllable environment. You don't have to have a computer, but it's
very nice. Pick any message with Meindert's name on it and his
tagline will give you the multiplexer's homepage. Nothing like live
support from the manufacturer right on the newsgroup, either, to make
a product really nice.

I know I can manage it either way, but I would hate to have to reorient my
brain each time I happen to switch off the Flux Gate or Yeoman.

Or should I set everything up so the Radar and Flux Gate are always on
together and get use to North Up again??

When I designed Lionheart's electronic suite, I vowed to simplify the
switching of all the electronic gear to a SINGLE SWITCH. This keeps
my captain from forgetting to turn off the XY Widget and leaving it
run for 2 weeks while he's away. So, I bought a 50A, continuous-duty
solenoid (looks like a Ford starter relay) and hooked 50A DC service
to it from the primary wiring of the house batteries. This relay
feeds two DC breaker panels, one at the chart table and one at the
helm where all the electronics in the whole boat are connected. No
breaker ever has to be turned off, individually, to secure the boat.
The main relay is switched by a nice push-pull brass switch with a big
red indicator that also serves as "Main Cabin Nightlight" for good
night vision at sea. When the boat docks, you press the big knob IN
and every piece of electronics gear from the B&G electro-hydraulic
autopilot to the radar to the radios, except for the emergency VHF
running off another system from the starting battery, goes on or off
all at once. It's real easy to hook up and works great! The sonar
hasn't run unattended for 2 weeks since I installed it....(c;

Or is it possible that the Yeoman can provide radar plots with the radar
remaining in Bow UP mode?? (seems like it is all relative plotting then)

The display of the radar plotter is not connected with the Yeoman's
output data in any way. The Yeoman will provide waypoint data to any
radar display orientation as it merely presents lat/long data of the
waypoint to it.

Confused, need help??

A word of caution about your network. Redundant gadgets are really
nice....AS LONG AS THEY ARE NOT TALKING TO THE NETWORK AT THE SAME
TIME! Make sure only ONE GPS is sending RMC, not two.....or one
compass sensor, not two....as they never read the same, anyway.
Lionheart has two compass/gyro data sources, the Raymarine Smart
Heading Sensor hooked via SeaTalk to the radar/chartplotter...and the
compass sensor built into the B&G Network Pilot autopilot. I can't
turn off the autopilot's compass sensor output data and B&G never
answered my emails regarding any undocumented control sequence to do
so. I can turn off the Raymarine compass data from the RL70CRC Plus
display unit, though and that stopped us from having TWO conflicting
compass headings driving everything on the network just crazy! Same
goes for the Garmin GPS data and the Raymarine Raystar 120 Seatalk
coming through the RL70CRC Plus translation. I have a toggle switch
in the NMEA output of them so I can select which GPS data stream the
system uses, clearly marked. Only one is selected at a time, normally
the Raystar 120 which is WAAS-GPS 3 meter accurate.

Don't get too cute making the system complex. It's neat but a pain in
the ass.....

One more tip......

If you own a notebook computer that has a common serial port in it,
you have a GREAT NMEA troubleshooting data analyzer! Take a DB-9
connector from Radio Shack and connect up two fleaclips to it.
Connect the red (hot?) clip to DB-9 connector pin 2 (data input to the
PC) and the black (ground?) clip to pin 5 of the DB-9. Boot Windoze
and open regular old Hyperterminal by clicking START then pointing to
ACCESSORIES then COMMUNICATIONS then clicking Hyperterminal.

When you connect the red clip to any point on any NMEA dataline,
inputs to the multiplexer or the network's master output, the display
will SHOW you what all the listeners are hearing, a data stream of
NMEA standard statements like $IIRMC and a bunch of data
numbers/letters. If you get a bunch of queer-looking graphics on the
display, you either have more than one talker hooked to it at a time
OR there's a data overload pulling down the data so the serial port
can't tell what's high or low at the appropriate moment. The other
condition is NUTHIN', NADA, DEAD.....when one of the damned wires is
shorted to something else.....(c;

It's a great troubleshooting tool for data, too! If you see two
different RMC statements with conflicting data, you'll easily find out
why the autopilot or plotter is going crazy. The first two letters
after the $ sign is the talker's address. Disconnect them one at a
time if you don't know what it's supposed to be and you'll see that
talker's statements missing from your display....

Sure is nice to be able to READ what's going on in there! Invaluable
and most guys already have a windows notebook just sitting there.....

PS - Hyperterm CANNOT be hooked to COM1 at the same time as the
navigation software. Only one Windoze program can talk to a com port
at a time....

Stop by Lionheart and I'll let you carry the WIRELESS chart plotter up
to the bow, running the boat from a beanbag in the sunshine....(c;