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Author Topic:   SIMRAD: New WM-3 Sirius Weather Receiver
bluewaterpirate posted 02-15-2013 08:33 AM ET (US)   Profile for bluewaterpirate   Send Email to bluewaterpirate  
Simrad redesigned its Sirius Weather receiver. It's a step in the right direction I just wish they had chosen to power and control it via the NMEA-2000 network like the Garmin GXM-51 Smart Antenna. It will be interesting to see if this new module migrates to the Lowrance side. I makes for a much smaller install footprint.



jimh posted 02-15-2013 11:21 AM ET (US)     Profile for jimh  Send Email to jimh     
When Lowrance offered an incentive on their LWX-1 Sirius receiver about a year ago, essentially giving it away for free if one subscribed to Sirius, I speculated that a new model might be in the works. It looks like it took a while, but we now have a new model. The WM-3 is much more compact than its predecessor.

Re powering from the NMEA-2000 network: usually only very low power sensors can be powered directly from the network. I don't know the exact limit on how much current a network device can draw, but my impression is not much power consumption is allowed for any one device.

jimh posted 02-15-2013 11:26 AM ET (US)     Profile for jimh  Send Email to jimh     
Since Kevin has a compatible Simrad chart plotter, I will expect him to buy a WM-3. I volunteer to help Kevin install it. If I cruise with Kevin I will subsidize his expense for the weather data subscription at a rate to be negotiated later.
bluewaterpirate posted 02-15-2013 01:29 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
The Garmmin GXM 51 Smart Antenna is connected to and powered by the N2k backbone.
jimh posted 02-15-2013 01:37 PM ET (US)     Profile for jimh  Send Email to jimh     
I don't think that NMEA-2000 has the bandwidth available to transport high-quality stereophonic music that has been digitally encoded. Nor does it likely have the bandwidth to transport the radar video. It seems like NMEA-2000 could not be used to carry the audio and video.

It would not be a problem to provide power to just the satellite receiver, assuming the technology of the Sirius receiver has progressed to the point of sufficiently low power consumption. I don't know what the precise limit for power for a network device happens to be. I think it is rather low. The network is supposed to support at least 100 devices. The typical network power is fused at about 3-Amperes. That suggests that no device ought to consume more than 0.33 amperes. If the receiver had really good, modern, low-power consumption, then there is a chance it could be powered directly, like a GNSS receiver.

The output of a GNSS receiver is just slow-speed serial data. The output of a satellite receiver for Sirius music and weather has to be at some point stereo audio. That is too much data for NMEA-2000 to carry.

I can see that extending control of the device via NMEA-2000 might be possible. But if you have to connect to it with a wider bandwidth network to get the audio and video, I am not sure why NMEA-2000 could be especially critical. You'd already have control via another method, which I presume is Ethernet.

bluewaterpirate posted 02-15-2013 03:31 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Interesting discusssion.

The Garmin GXM 51 is connected to and powered by my N2k backbone. All data from the antenna to the 740 and the subsequent audio output is via the N2k backbone. My Simrad NSS8 sees the GXM 51 on the backbone.

I know why Navico didn't choose NMEA-2000 connectivity: it's because they would have to do a rewrite of their Sirius Weather connectivity and functionalities.


jimh posted 02-15-2013 03:53 PM ET (US)     Profile for jimh  Send Email to jimh     
Tom--Thanks for the illustrations of your installation, They show just what I said: the audio is not carried on the NMEA-2000 network. The receiver has a separate cable that delivers the audio as baseband audio to the amplifier.

The weather overlay video is probably sent at low speed, since it is not refreshed very often. The weather image is probably only updated at a relatively slow rate, perhaps only once a minute. At that rate of data, you could send the video over NMEA-2000. Garmin must have employed their own special NMEA-2000 parameter groups to transport the weather image from the receiver to the chart plotter over NMEA-2000.

I don't have clarity about your set up on this: does the Simrad plotter show the weather data from the Garmin receiver on the Simrad chart display?

bluewaterpirate posted 02-15-2013 06:37 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Actually the refresh rates are very high because both XM & Sirius both use animation in regards to NEXRAD/NOWRAD, XM cloud cover. XM/Garmin is better with animation than rSirius/Simrad.

Short video ......

The NSS8 GXM 51. The 740 has a volume control component in that it can control the volume of the music coming from the GXM 51 before it is forwarded to your stereo. The NSS8 doesn't have that capablitiy.


jimh posted 02-16-2013 08:59 AM ET (US)     Profile for jimh  Send Email to jimh     
Tom's video shows the animation. But that animation may only change every few minutes. The animation data may take 60-seconds to be sent over the network. Then the plotter shows the data as an animated video, which moves at a rate of once per second. The real update rate is how often the total animation changes.

As Tom suggests, the new model from Simrad is using the same interface as the old, Ethernet, to send the video from the receiver to the chart plotter. I don't see this as a big drawback.

Tom--I am still not clear about one point: Is your Simrad chart plotter able to show the weather data from your Garmin weather radio? And, can the Simrad control the Garmin?

I think Tom has a two weather receivers, one connected to his Garmin chart plotter and a second one connected to his Simrad plotter. Is that right?

bluewaterpirate posted 02-16-2013 01:34 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Yes, I have both XM & Sirius weather modules (gxm51 & wm2).
bluewaterpirate posted 02-18-2013 12:17 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Sorry, I didn't articulate my point in a more concise manner. What I was trying to say, "Is by using the N2k backbone you preclude the need for two connections (one for power and the other for data). In the case of the Garmin GXM 51 Smart Antenna all you do is connect to the N2k backbone. And yes there is a another connection for the music component.

When using the Garmin GXM 51 you have two dislays that show you the time in minutes all weather updates we made. XM%20vs%20Sirius%20Marine%20Weather/29JAN12_1613_00.jpg XM%20vs%20Sirius%20Marine%20Weather/29JAN12_1613_01.jpg

The Simrad WM2 software doesn't have these displays.


jimh posted 09-27-2013 11:00 AM ET (US)     Profile for jimh  Send Email to jimh     
Some time ago I speculated that Lowrance would be offering a new satellite weather receiver because they were offering extremely attractive incentives on their current model, the LWX-1 marine weather receiver. Now Lowrance has adopted the WM-3 receiver for their chart plotters. The Lowrance website now lists the WM-3 receiver for use with HDS Gen2 devices, specifically all HDS Gen2 or HDS Gen2 Touch chart plotters.

The WM-3 SiriusXM Satellite Weather and Radio Module is priced at $799, a substantially more expensive receiver than the old LWX-1, which, with rebates, was essentially free.

What you get for $800 is a receiver that is said to operates with the new SiriusXM North America equatorial Satellite System. I believe this refers to the transition of the XM services from satellites in high tundra orbits to a satellite or satellites in geo-stationary orbit. (I find this feature a bit confusing, as I think it has been a feature of Sirius and XM all along that their receivers can use more than one satellite source.) An excellent summary of the history of the satellites used by XM and Sirius (which were two separate companies until they merged) is provided in an article at The launch of Sirius FM-6 or Radiosat-6, an new satellite for equatorial or geo-stationary orbit, is still being awaited. suggests the launch will be October 9, 2013.

For your $800 the WM-3 gives you a smaller antenna-receiver assembly than previous receivers, and a break out cable that provides for Ethernet (to interface with the chart plotter), power, and two-channel stereo audio (on RCA connectors for your audio amplifier system). There is no NMEA-2000 connection.

The subscription levels are explained in

There is a bit of confusion as the labels used on the display of the software controlling the receiver are somewhat different than the names used by Sirius for the service levels.

jimh posted 09-27-2013 11:20 AM ET (US)     Profile for jimh  Send Email to jimh     
To offset the $800 MSRP of the WM-3, there presently is a $100 rebate incentive and free subscriptions to various services. For details of the offer see

By the way, I will have to sit on the sidelines on this new receiver. I don't have the requisite HDS Gen2 chart plotter, and I am not inclined to spend $800. In retrospect, that free offer on the old model receiver looks like quite a good deal.

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