Buying an AIS transponder, which VHF radio to buy to effectively use it?

[bensolomon]

Oops. I'm embarrassed. It was a tough day at work. I use The Cruisers Forum as a mental break from from work during the day. Today was unusually stressful and therefore I had on some Rose Colored Glasses. Having reread the post, I understand the context of the post, now that it has been pointed out to me. To Jeff Robbins, I sincerely apologize. To islandhopper and sailjumanji, I appreciate you pointing out my error.

Again, Jeff, I'm sorry.

Ben

[sailjumanji]

You are a big man, Ben. Good on you!

[jeffrobbins]

No need to apologize Ben. But thanks and it's appreciated. I'll try to be less ambiguous in future posts. I just wanted to be transparent.

With regards to your post.... the Vesper units do have a multiplexer for integrating incoming 0183 but they only have a single 0183 output. Newer VHF radios will accept 38400 baud input for their GPS and/or AIS data so it's not a problem to feed both the plotter and the VHF from a single 0183 output. It's only a problem when the VHF requires a 4800 baud input. In many configs the plotter has N2K or Seatalk-NG so in that case the 4800 baud doesn't present an issue either.

You are correct that the Vesper units don't have a built-in splitter and we did that for a few reasons. One is to keep the cost as low as possible since not everyone needs that. The second is to allow greater flexibility in where it is mounted. On some boats there isn't sufficient room to mount it right next to the VHF (as that's where the antenna cable terminates). We also make screen-based units where it could be an installation issue to have to run two antenna cables to the screen. Finally, it allowed us to make a much higher performing splitter than what is embedded in transponder units like the DY and others.

But even with a separate splitter (which I admit does mean installing another small box) the price of an XB-8000+SP160 is still competitive and a quick look on a popular website shows it to be less than the AIT3000.

1) Can my XB-8000 (through the app) trigger a VHF call on an iCom radio? If that were possible, I'd toss my B&G radio overboard and buy an iCom in a heartbeat. (OK, I'd actually recycle it responsibly. But I'd THINK about tossing it over!)

Well, great question... The XB-8000 can indeed control an ICOM radio and do a direct DSC call just like a WatchMate Vision. But our apps don't yet have that feature to tell it to do so. It's on our to-do list for the apps. We've just been really busy lately on some other new stuff and haven't gotten a chance to do it. I wonder if there is generally high interest in this?

2) Can you direct me to the page where it lists the N2K data types that the XB-8000 sends over WiFi? You've mentioned before that new data types are being added regularly, I hope that's still happening. I'm hoping some day to see engine data. All that environment stuff is of less use to me on a power boat

The way this works is N2K PGN's are received and translated into corresponding 0183 sentences which are then fed into the output stream and appear on the various output ports (WiFi, USB, 0183). This is why it works with all 3rd party apps and even means you could use an older 0183-only plotter with new N2K nav instruments although I don't know how many people actually do that.

But it also means that there needs to be a corresponding 0183 sentence for the N2K PGN. That and we need to find a little time to implement the translation.

There's a list of PGN's received and transmitted at: https://www2.vespermarine.com/guide/xb8000/
And the N2K->0183 translations are at: https://downloads.vespermarine.com/d...anslations.pdf

Jeff

[CaptTom]

Originally Posted by jeffrobbins

The XB-8000 can indeed control an ICOM radio and do a direct DSC call just like a WatchMate Vision. But our apps don't yet have that feature to tell it to do so. It's on our to-do list for the apps. We've just been really busy lately on some other new stuff and haven't gotten a chance to do it. I wonder if there is generally high interest in this?

Thanks for the detailed replies! I certainly understand your position; you quite correctly want to address the highest-demand features, as well as keep a focus on development of new stuff. In my opinion, Vesper is one of the few companies which does this very well.

But also consider this perspective. Writers of reviews in magazines and on line love something that's colorful, very simple to learn and has very little functionality. Beginners and first-time buyers want the software and hardware with the fewest buttons, options and features to learn. They submit negative reviews if there are too many "complicated" features they don't understand.

But I think this can lead to software and hardware development to the lowest common denominator, and to mediocre products.

Listening to the small number of "power users" who actually USE the system routinely may not seem to have much value for a mass market, but I believe it leads to a better product. This earns respect and "buzz" in the user community, and brings positive name recognition.

Originally Posted by jeffrobbins

There's a list of PGN's received and transmitted at: https://www2.vespermarine.com/guide/xb8000/
And the N2K->0183 translations are at: https://downloads.vespermarine.com/d...anslations.pdf

Thank you for the link to the NMEA translation list. I notice the date on it is August of 2016, so I guess that hasn't gotten much focus lately.

[jeffrobbins]

Thanks Tom for your understanding and words of encouragement. We find it difficult to explain all the complicated in's and out's while struggling to find ways to present products in a simple and approachable way for non-"power users" to easily understand yet make sure advanced users know about all the capabilities. And when presenting products in their simplest form (eg. it's an AIS transponder) then how do people compare and differentiate it from the other products on the market?

You're absolutely right about listening to real users and I try to keep my nose in this forum as often as I can. But like all relatively small enterprises we've got to pick and choose and balance the tradeoffs against new development too.

Originally Posted by CaptTom

Thank you for the link to the NMEA translation list. I notice the date on it is August of 2016, so I guess that hasn't gotten much focus lately.

It was probably November (we do dates opposite down here) but that makes little difference since it's still been awhile since we got back to that I'm afraid.

[CaptTom]

Originally Posted by jeffrobbins

It was probably November (we do dates opposite down here) but that makes little difference since it's still been awhile since we got back to that I'm afraid.

I see what you did there

No worries. All that extra data is just gravy. The core functionality of my XB-8000 is rock-solid, and I greatly appreciate the fact that it's still supported AND updated more than three YEARS after I bought it. Others in your line of business could learn something from that!

[bensolomon]

Jeff,

Thanks for the clarification, and again, I apologize. My real issue is I want to keep using my old Garmin420 chartplotter, and have AIS on it and keep my DSC connection to the Icom 503 vhf. The trouble is the 420 is only 0183, and only allows me to select one baud rate for both in and out. That's where I need the multiplexer.

I didn't think the vx8000 could send two separate baud rates out.

I'll have to read the technical details more closely.

[ronstory]

Well, my plans from starting this thread have morphed a bit.

I got the mast reinstalled with the LCJ Capteurs CV7 at the tops and a lot of other cables. Cabling things together took longer than expected (sigh) and I have it almost all together. I ended up with the Simrad RS35 and couple of HS35s.

I also installed Raymarine C97 at the Nav station and a Raymarine A68 at binnacle. Now I'm doing the final wiring after pulling 25 lbs of old wire out and routing the new wire in "new and interesting" paths to get it where I needed. ... and 'yes' there are a few knew holes in the boat for wiring... but all above the waterline.

Now the last piece of equipment I need to buy is the AIS transponder. I've picked the Vesper VHF spliter/duplexer... but now need to pick the actual transponder. I like the reviews and feedback on the XB-8000... but have been reading some review on the new SOTDMA transponder from AMEC and available at MillTech Marine in Washington... and it's about $150 more for the wifi version vs the Vesper.

The benefits of a SOTDMA versions seems to be 5 watt transmit and faster update. That said, I'm a sailboat... we don't do anything fast by power boat standards.

Anyone using a SOTDMA AIS transponder? Any feedback welcome.

PS: I'm glad I didn't wait for the SH GX6500... it's been more than a year and no approval. (sigh)

[DotDun]

Originally Posted by ronstory

Well, my plans from starting this thread have morphed a bit.

I got the mast reinstalled with the LCJ Capteurs CV7 at the tops and a lot of other cables. Cabling things together took longer than expected (sigh) and I have it almost all together. I ended up with the Simrad RS35 and couple of HS35s.

I also installed Raymarine C97 at the Nav station and a Raymarine A68 at binnacle. Now I'm doing the final wiring after pulling 25 lbs of old wire out and routing the new wire in "new and interesting" paths to get it where I needed. ... and 'yes' there are a few knew holes in the boat for wiring... but all above the waterline.

Now the last piece of equipment I need to buy is the AIS transponder. I've picked the Vesper VHF spliter/duplexer... but now need to pick the actual transponder. I like the reviews and feedback on the XB-8000... but have been reading some review on the new SOTDMA transponder from AMEC and available at MillTech Marine in Washington... and it's about $150 more for the wifi version vs the Vesper.

The benefits of a SOTDMA versions seems to be 5 watt transmit and faster update. That said, I'm a sailboat... we don't do anything fast by power boat standards.

Anyone using a SOTDMA AIS transponder? Any feedback welcome.

PS: I'm glad I didn't wait for the SH GX6500... it's been more than a year and no approval. (sigh)

I would buy the SOTDMA Class B and not invest in the older CSTDMA at this point.

[jeffrobbins]

Originally Posted by DotDun

I would buy the SOTDMA Class B and not invest in the older CSTDMA at this point.

I'm really curious why?

There are two significant differences between the two. B/SO has 5W transmit power vs. 2W for B/CS and B/SO has a speed-dependent transmission interval for position reports. The higher power output affects transmission but not reception. The standards for reception are identical so you won't gain any advantage there.

For transmit you might get a slightly greater range but the largest influence on range is the antenna system installation. Factors like antenna frequency (AIS freqs are at the edge of typical VHF antenna bandwidth hence the recommendation to use an AIS tuned antenna), antenna design & construction, cables and other losses but most importantly height. Height makes a far greater difference than power output. In general, once you get past about 1W transmit power, line of sight becomes the limiting factor. And for collision avoidance the class B design transmit range of 7-10nm seems appropriate.

However, the transmit interval for position reports is much more important in my opinion. But you can see from this table that it only matters for vessels >14 knots and makes a significant difference when above 23 knots. If your boat is <=14 knots then there is no difference at all.

In busy locations then there's only a difference when >23 knots (twice the reporting interval for B/SO in that case).

That's all consistent with the general intent of B/SO. It's intended for fast commercial boats that otherwise don't require a Class A.

So if your boat is >14knots, and more particularly >23knots, then I would recommend considering B/SO. Otherwise I recommend looking at other aspects of the AIS transponder's capabilities, especially considering the currently available B/SO units are pretty basic otherwise.

I'm very curious what others think though.

[DotDun]

Originally Posted by jeffrobbins

I'm really curious why?

There are two significant differences between the two. B/SO has 5W transmit power vs. 2W for B/CS and B/SO has a speed-dependent transmission interval for position reports. The higher power output affects transmission but not reception. The standards for reception are identical so you won't gain any advantage there.

For transmit you might get a slightly greater range but the largest influence on range is the antenna system installation. Factors like antenna frequency (AIS freqs are at the edge of typical VHF antenna bandwidth hence the recommendation to use an AIS tuned antenna), antenna design & construction, cables and other losses but most importantly height. Height makes a far greater difference than power output. In general, once you get past about 1W transmit power, line of sight becomes the limiting factor. And for collision avoidance the class B design transmit range of 7-10nm seems appropriate.

However, the transmit interval for position reports is much more important in my opinion. But you can see from this table that it only matters for vessels >14 knots and makes a significant difference when above 23 knots. If your boat is <=14 knots then there is no difference at all.

In busy locations then there's only a difference when >23 knots (twice the reporting interval for B/SO in that case).

That's all consistent with the general intent of B/SO. It's intended for fast commercial boats that otherwise don't require a Class A.

So if your boat is >14knots, and more particularly >23knots, then I would recommend considering B/SO. Otherwise I recommend looking at other aspects of the AIS transponder's capabilities, especially considering the currently available B/SO units are pretty basic otherwise.

I'm very curious what others think though.

SO guarantees a time slot, CS does not. 5w is more than 2w. Price difference is negligible.

[ronstory]

Similar to my thoughts. If I had a working CSTDMA 2W AIS in our sailboat, I'm pretty sure I wouldn't update to SOTDMA.

However, if I was buying new I would be willing to pay a bit more for "new and more".

SOTDMA is same protocol that Class A uses for commercial vessels versus the "lighter" version CSTDMA used in the 2W Class B.

As for the power diff between 2W and 5W in the VHF band, its only about a 4dB signal difference... but sometimes that can make the difference when you are in marginal conditions.

That all said, a good antenna placed high and in the clear counts for a lot of dB of signal.