TCP Connection Problems on Apple iOS 10


Since Apple’s release of iOS 10 for iPhones and iPads, we have been getting a number of calls and emails saying that various navigational Apps that read wireless NMEA data from our products have stopped working, including our free iAIS app.

There are two modes/protocols that our wireless NMEA products can work in; TCP which is a reliable one to one type connection supported by most apps and UDP which is a broadcast protocol that allows multiple devices to all receive the same data.

When we started to investigate, we found that TCP communication on all Apps no longer worked with iOS 10 and UDP only worked on some apps. At first we thought this might have been an Apple API type change that had caused the problem, but then we discovered that changing the IP address of our wireless NMEA products from to fixed the problem.

The IP address range is usually reserved for Ad-Hoc networks where there is no DHCP server and dates back to our first iAIS product (released in 2011) that only supported Ad-Hoc networks. With the release of Android, which did not support Ad-Hoc networks, we updated our wireless NMEA products to the more common Access Point mode but retained the IP address, to avoid changing too many Apps and Documentation.

Now it seems that Apple are clamping down on TCP connections on Ad-Hoc networks and this means that all customers who have updated their iPhone or iPad to iOS 10, will need to change the IP address of their wireless NMEA product, if they have one of our; iAIS, WLN10, WLN10HS, WLN20, NavLink, PilotLink or AIT3000 units. Please note that our iNavHub and Sonar Server products are not affected by the iOS change.

To make this procedure as easy and simple as possible, we have created a new Tech Note that explains what needs to be done. Click here to download.


Wi-Fi Congestion


The range of 2.4GHz frequencies reserved for Wi-Fi is fairly limited and with so many Wi-Fi devices and networks these days, it is not unusual for wireless networks in the same location to share the same frequencies and this results in lower connection speeds and even connection drop outs in extreme situations.

The good news is that the wireless network(s) on your boat, once out at sea, will not be affected by the wireless networks on land or on other boats. That said, these days it is not unusual for larger yachts and powerboats to have two or more wireless networks and so it is really important to ensure that your own wireless networks are working at peak performance and not sharing the same frequencies.

The good news is that most Wireless Routers and Access Points can be configured to work on a specific frequency and so you should be able to ensure that each network is using its own frequency band without any overlaps.

There are affectively 13 frequencies in the 2.4GHz range and each wireless router will use five adjoining frequencies to setup its network. Looking at the diagram above, where each coloured curve is a separate wireless router/network, you can see that in general three frequencies are used; 1, 6 and 11. which allows three routers to work side by side with no overlapping/sharing of frequencies.

So how do you optimise the frequencies used by your wireless networks ? Well first you need to “see” what is going on by carrying out a wireless survey of your boat. This can be done using a number of free programs and apps. Unfortunately Apple do not allow iPhones and iPads to provide this level of Wi-Fi Information so you will need to use a Windows PC or Android device to do your wireless survey.

If you have an Android phone or tablet, then you are in luck as the free App “Wi-Fi Analyzer” is one of the best tools available and created the image above. For Windows PC users then “NetSurveyor” is very good or “WiFiInfoView” which is not so graphical but is only a few hundred Kilobytes in size and needs no installation, so can run straight from your memory stick.

Whichever tool you use, once you have conducted your wireless survey, you will be able to see what frequencies your wireless networks are operating on and decide if you need to change them. All Digital Yacht wireless products can be changed to use a different frequency and should you need to do this, please contact us for instructions.

Navionics App + Digital Yacht WLN10 = Amazing Sonar Charts Live

The Navionic’s iOS and Android app has proved incredibly popular with boaters throughout the world and it’s now just introduced some game changing features.

The Miami Boatshow 2015 saw Navionics pick up the Innovation Award for their new Sonar Chart Live platform and the best news is that it’s designed for and compatible with our wireless NMEA devices – like AquaWear, WLN10 and NavLink.

The new version allows NMEA depth and GPS data to be integrated into the app allowing iOS devices (like iPads without the GPS feature) to utilise boat data when connected through a Digital Yacht NMEA-Wireless server.  Even if your iPad has GPS (the 3G/4G models), you’ll benefit from enhanced accuracies from your boat’s systems, better battery life and reception below decks – so your iPad really will be an integrated part of the boat navigation network.

But here’s the real plus….

Navionics can now record depth information from your NMEA connected instruments, depth sounder or fish-finder allowing a real time depth contour to be built onto your chart.   When connected to a WLN10 (details HERE), depth data is streamed to the app and shows an updated depth contour onto the detailed chart.

Watch the depth contours updated on you chart as you cruise.  Installation is easy – just like this via a simple 2 wire NMEA 0183 connection:

WLN10-01Here’s a picture too of what to expect – and when you see in real time, it’s awesome:

sonar 1

Collected data is then also sent to Navionics (when you have an internet connection) to be post-processed who then process and update your chart with a download – not just with your data but with other users too allowing for the best possible crowd sourced information.  As they say, “Want better charts? Go boating!”  Check out the video below

Testing Wireless NMEA Data

iAIS TCP-IP Screen


With more and more wireless NMEA systems being installed on-board boats, it is very useful for dealers, installers and enthusiastic end users to have simple tools to “view” this wireless NMEA data.

Traditionally, wired NMEA0183 data was viewed using an NMEA to USB cable connected to a PC and then a program such as Hyperterminal (included with Windows up to WinXP) would be used to display the data. In fact Digital Yacht released a free, dedicated NMEA Display program to use on Windows Vista/7/8 and this proved to be a popular tool for testing wired NMEA0183 systems.

With wireless NMEA systems it is much easier to test using a smart phone or tablet and we would recommend the following free apps;

For Apple iOS Devices – our own free iAIS app (see image above) has a very simple raw data view window that can be used to display the wireless NMEA data in TCP or UDP mode. Alternatively iNMEA Logger is another free app, written by the company that developed the popular iRegatta App that can log 30 seconds of received data and create a text file of the results, useful if you do not understand NMEA0183 and want to send it to someone who does.

For Android Devices – there are no specific wireless NMEA Apps, but there are a lot of terminal programs that display TCP and UDP data and after trawling through a fair number of apps, we came across TCP/UDP Terminal App which we think is the best Android App found so far.

Once you have installed your app for displaying wireless NMEA data, then you need to know what you are looking at. To buy the NMEA0183 Specification costs quite a lot of money but there is quite a lot of data on-line, you just need to hunt it out.

Unfortunately a lot of the information on-line is quite old and some of the newer sentences are not fully explained. The NMEA do in fact publish a complete list of all Sentence Identifiers with a short description of what they are (not the complete sentence description) and this list also includes the proprietary Manufacturer’s ID – these sentences start $Pxxx, where xxx = the manufacturer identifier.

It should be noted that most wireless NMEA data is “human readable” (ASCII Text) but the AIS sentences VDM and VDO have what is called a “binary encapsulated” section (bit like a zip file) to reduce the sentence length – see example below.


This means that you will not be able to make sense of the AIS target information in the VDM and VDO messages, but our free iAIS app does display this information on the main plotter screen, so worth having a copy of this app.

Surface Pro 3 Navigation & Charting

While Microsoft have had a hard time with their Surface tablet product, the latest generation really is a great product and may make a brilliant solution for on board navigation.  With an amazing 2160 x 1440 pixel 12″ screen it’s hands down better than pretty much any chart plotter and its portability means you can use at the chart table, in the cockpit or for planning at home.  It’s also priced like a 5″ plotter


The keyboard is detachable so you can use as a tablet (with touch screen, mouse or stylus) or in a more familiar notebook format which is good at a desk or chart table.  We also wrote about the Lenovo MiiX tablet (a smaller 8″ unit) HERE a few months back but Surface offers a bigger screen and a more powerful Intel based processor for superior performance.

But…  Unlike many tablets, it doesn’t have a built in GPS so until now was not a contender for on board navigation.  However, our WLN series nmea-wireless servers can stream your boat’s NMEA instrument, GPS and AIS data direct to any mobile device including iPads, Android tablets, PCs, MACs and now the Surface Pro.  This is a much better solution even if your tablet has an internal GPS as your on board system will generally be more accurate and have other data like AIS and instruments available.  It alos means the tablet will work below decks and save on tablet battery consumption.

You can of course use our SmarterTrack PC navigation program on a Surface Pro and this works well.  Swedish developer SeaPilot have just launched a FREE app on the Windows store and there’s a large selection of professional charts available to download for a modest cost turning the Surface Pro 3 with a WLN10 into a pretty powerful navigation solution.  Here’s a quick 2 minute video with Jens Johansson from SeaPilot when I caught up with him at Boot 2015

Going wireless on a B&G Hydra 2000 System

Hydra 2000

An owner of a J109 contacted us this week to see if there was any way we could breath new life in to his B&G Hydra 2000 racing instrument system. Much as he would have liked to install a complete new instrument systems, high performance racing software from Expedition and a couple of wireless tablets, after being forced to buy a new set of sails, his budget was seriously depleted.

The Hydra 2000 performance instrument system from B&G was really popular with racing yachtsmen in the late 1990s and early 2000s and although it has been replaced by the H3000 system for the last 10 years, there are still a lot of boats with these systems and it is a tribute to B&G that many are still giving good service.

The basic system consisted of the transducers, feeding in to the main processor unit and displaying the data on a series of Full Function Displays (FFDs) and large 20-20 displays. In order to get data out of the system, you needed to have an 8 button NMEA FFD and this was connected to the system via a round white NMEA junction box. The plan was to connect our WLN10 Wireless NMEA Server to the FFDs NMEA output and then to wirelessly stream the NMEA data to the popular iRegatta App running on an iPad.

Identifying the right wires was not so easy as both the NMEA Input and Output pairs of wires were Red(+) and Blue(-) but opening the NMEA junction box and looking for the Violet NMEA Output(+) wire from the FFD was the best way to identify them. Then it was just a case of connecting up the WLN10 as shown below, turning the system on and ensuring that the Yellow “Data” LED on the WLN10 started to flash.

B&G Hydra 2000 to WLN10

Once installed any wireless computer/tablet/phone could be connected to the WLN10 and with suitable software/app receive the wireless NMEA data. This particular customer had installed iRegatta on his iPad (£13.99) and was very impressed when all of the instrument and GPS data suddenly started to appear on the displays. With performance racing features, polar calculations and good logging/analysis facilities iRegatta seems to be excellent value and very useful for club racers or  in fact any yachtsman who likes to get from A to B in the quickest, most efficient way.