Regards

I have a question about VHF antenna mounting locations. I realize the best location is up high. My carbon mast is 70' above the water. But with that distance and corresponding reduction in power, plus weight of the cable(s), desire for AIS-B, a Lopolight and Airmar PB-200, is it feasible to mount the VHF antenna on a radar mast which is 10' or so above the water? My thinking here is that with less power loss and a higher quality antenna, the effective range may not be substantially different (or substantial enough to be a practical hindrence to coastal New England cruising) and the cleanliness of the installation/maintenance is a valid trade-off.

Thoughts?

Even if NMEA2000 is meant to be "plug-and-play" I see one major problem with choosing another brand. All calculated wind information, such as True Wind etc, is calculated from boat speed but the calibration of the boat speed is stored in the instruments and not in the sensors unlike, for example, depth. In the network only the measured boat speed is distributed and not the calibrated one.

When I calibrate the boat speed in one of my IS20 Graphics the wind information on the Wind instrument will change accordingly. It is not, however, possible to make the calibration in the Wind instrument itself so if I were to put the instrument in a network that would not have any Simrad instruments I would not be able to calibrate the boat speed in order to make the IS20 Wind instrument show the correct wind information.

The reason I have previously been looking at Garmin's GMI10 is that it is also capable of showing boat speed, which therefore must be possible to be calibrated. I have also looked at Furuno and Raymarine but I have not been able to retrieve enough information about their instruments to judge whether the boat speed can be calibrated in their wind instruments.

Has anyone else tried to combine instruments from different brands the way I am describing above?

Johan Hackman
Hanse 342 #306, S/Y Emilia

It looks fine to me, though I wonder if all the field attachable connectors along the backbone are necessary.  I think they're valuable if you have a tight cable run, but otherwise pre-made cables are easier, more robust, and less expensive.  I'd also flip some of those tees around so the gender progression was more orderly.  It's a nuance, but the idea of the Maretron power tap with its two female connectors is that cable genders go M/F/M/F/M/F all the way from there to terminators and all devices.  That way if you ever break open the network when it's powered up you won't expose male pins that are hot.  There's no good reason I can think of to have M/M or F/F cables.

Download Bob's NB2 file here:  Ombre_Rose_4_N2K.n2b

-barry

I have a SimNet network on my boat with a Maretron DST100, a Simrad wind vane, a compass sensor and a GPS antenna connected to a couple of IS20 instruments. Now I wish to add a GMI 10 to this setup.

I have a NMEA2000- to-SimNet adapter that I used to plug into the GMI 10 and a T-joiner in the network. It has an NMEA2000 plug at one end and a SimNet plug at the other. If I understand it correctly, all I would have to do was to press and hold the power button to fire up the instrument but nothing happened!

I have made sure that there is 12 V in the connector and have double-checked with the installation guide that I should not use the supplied power cable if I am connecting the GMI 10 to an existing NMEA 2000 network that is already powered. The adapter I am using works fine for powering the Maretron DST100 hull sensor so I don't see why it couldn't power the GMI 10.

Could anyone give me a hint about what I am doing wrong here?

Johan Hackman
S/Y Emilia
Hanse 342

- Design out any unnecessary components for cost savings
- Ensure that it's expandable in the future (using mid-cable as backbone)
- Decide between a Airmar PB 200 on the mast or a Furuno FI-5001 Wind Sensor (Would go with FI-5001 to reduce cost)
- Ensure this is the smartest design for my application

I've already decided on/purchased the FI-501 Wind and FI-503 Digital and have a Airmar DST-800 installed in the vessel (N2K version, not hooked up to anything right now).

I'm planning on going with a Lowrance HDS-8M chart plotter but am open to options.

I plan on using the HDS-8M as the GPS sensor, making the assumption that it will feed the GPS data onto network to be read by my Mac laptop running MacEnc.

Couple of questions:
The airmar DST-800 claims a LEN of 4 (http://airmartechnology.com/uploads/brochures/DST800.pdf) while the Maretron DST100 claims a LEN of 1 (http://www.maretron.com/products/pdf/DST100-Data_Sheet.pdf). That seems strange to me?

The HDS-8M claims a LEN of 1. That seems low to me, I am assuming this is because the HDS also has a separate power hook-up.

If I end up going with the Furuno 5001 as my wind sensor, will it feed the data onto the N2K network via the daisy chained FI-501?

Is it better to go with field attachable cabling or pre-built N2K cabling?

What is the best way to go from the N2K to 0183 to USB for Laptop? Could I wire the digital yacht 0183 USB to the 0183 wire on the HDS-8M and expect the HDS-8M to feed N2K data over to the 0183 port then to the laptop?

N2K Builder Files and network pictures can be found here: http://www.svkaleo.com/the-vessel/n2k-network/

Ben, feel free to repost them on this forum, I just couldn't figure out how. {Done below, B.E.}

Thanks in advance for the help, Matt
www.svkaleo.com

"Data packets on the network are limited to 8 byte groups and where it is required to send longer messages these are grouped together in what are called "fast packets" which are groups of 8 bytes to a maximum length of up to 233 bytes. NMEA2000 certification currently requires all certified devices to be able to handle 2 concurrent interleaved fast packet incoming messages into two buffers, decode and assemble the messages in real time and when the message is complete hand it to the computer to process it and free up the fast packet buffer. The standard states that if a device starts to receive a third fast packet message whilst still assembling the first two then the third message is to be abandoned.

What is happening is that on heavy used systems, and yours is certainly one of these, traffic levels can be such that this can sometimes occur."

I find it difficult to accept that my system is classed as heavily loaded!

Any experienced responses appreciated.

I would like to add a wind instrument and am looking at the Maretron MB100 or the Airmar PB200 - recommendations?

I have two computers at the helm - Weather Worx and video cameras. I am thinking I will install Coastal Explorer.

If I put N2K onboard, I am thinking the Maretron engine monitors for my Yanmar 4JH3-hte(s), and then the Maretron ultrasonic level monitors for fuel, water, holding.

What should I be considering or looking at?

Thanks
Henry

Here's a design that neatly shows how N2KBuilder can be used with non-Maretron devices.  If Jon Kinne entered the right LEN values into the properties of those various Airmar, Simrad, and Actisense boxes, then N2KBuilder's current and voltage calculations should be about right. But that might change if Jon takes my suggestion of dropping the multiport and just using one Devicenet-to-Simnet patch cable in the NavPod, with two short SimNet cables daisy chaining to the other instruments.  I'm confidant that such a cabling system will work fine for this network, but note that N2KBuilder does its calculations based on the sort of certified N2K cable that Maretron sells, and non-certified cable doesn't necessarily have the same power and data carrying abilities.
    Jon's N2B file is here, and he describes the system thusly:

"Here is the diagram of my new proposed N2K network aboard Indigo. I will use the terminator built into the PB200, and the multiport will be in the NavPod at the helm.  I only need 60' of the Airmar cable to run down the mast, and the extra will be used to connect the backbone to the NavPod (12' max).  The NGW-1 will take 0183 sentences coming from my ShipModul multiplexer and translate them to 2000 for the N2K instruments.  The MUX receives input from a Garmin GPS, DSC information from the VHF and communicates with Nobeltec Max-Pro VNS via USB."

Bob Bergoffen sent in another NMEA 2000 design with an interesting twist or two:

"The attached N2B file is the actual N2 K installation aboard my Gozzard 36 Ombre Rose. All components are Maretron except the Simrad Autopilot. All wiring is Maretron micro with a lot of field installable connectors. Most of it was done before they came out with the mid sized cable. I ran the design calculations with the input voltage at 10.5 volts input and there were no voltage problems in the system.
   I have been using the DSM250. I continually update it with it with Maretrons N2K Analyzer. It now includes alarm capability and a very nice anchor watch setup. When i can afford it I will switch out the DSM 200 for another DSM 250 at the Nav. station. I am adding another TLM 100 for my fresh water tank and would like to add either an Alba or Marerton engine monitor for my older Westerbeke diesel engine. Comments would be greatly appreciated."

N2KBuilder isn't really designed to show the physical lay out of a network, but Jeff Shukis figured out a way to do it, and it works pretty well, I think. He also used the "don't include in BOM" command to gray out devices and cables that he has not yet installed on Beneteau but plans to.  That way he could set the powertap at a worst case 10.5v and see that his blue Mid backbone and micro drop cables delivered sufficient juice. Jeff's .nb2 file is here, and the floorplan .jpg file here. Both files have to be in the same folder to work (and "desktop" did not work on my PC).