HF-AIS is an advanced technology that ensures an AIS transceiver reliably processes all transmissions in real time without error. An AIS transceiver with HF-AIS will typically allow you to see up to 30% more targets than transceivers without HF-AIS. All Digital Yacht transponder products incorporate this technology brought to us by our chip set manufacturer SRT
You don’t know what you don’t see – if your AIS transceiver does not process (decode) an AIS transmission, you will not see that target on your display. This issue affects AIS Class A, Class B and receivers.
HF-AIS technology solves this critical and unseen issue, which can result in you missing up to 30% of available targets and data. An AIS transceiver can be required to receive and then decode up to 2,250 transmissions every minute – 37 every second – with each AIS transmission containing up to 300 bytes (your GPS position, MMSI, Speed, Course etc), that’s a huge amount of information that must be continuously processed. When this data is not processed due to the transceiver being overwhelmed with transmissions, the data is lost forever – often up to 30% of targets. The lost transmissions could be from a nearby vessel on a collision course with you – therefore lost data and targets are of critical importance to your safety.
Proven to see up to 30% more AIS targets and data with HF-AIS
HF-AIS ensures all available AIS transmissions are fully decoded and processed in real time.
HF-AIS is advanced core technology, that combines hardware and software, embedded in the ‘processing brain’ of our AIS transceivers.
HF-AIS is particularly beneficial in busy areas where the volume of AIS transmissions can cause processing errors and lost data in transceivers without HF-AIS.
HF-AIS technology is a unique combination of hardware and software embedded within
our AIS transceiver. It comprises a high performance processor (chip) which has the processing speed to easily cope with reliably decoding large amounts of data in real time
on which is highly efficient software that uses specialist architectures and structures
normally found in data heavy wireless applications such as 3G and 4G cellular phones.
This unique combination of hardware and software is HF-AIS and ensures that our
transceivers will reliably process all available AIS transmissions in real time and without
The ultimate benefit is that you’ll get outstanding performance and the best AIS capability from our transponders.
You can see the effect of the technology in action HERE
BoatBeacon (a company with some brilliant marine telematics capabilities) are rapidly expanding their AIS base station coverage and utilising Digital Yacht AIS products for exceptional performance. A recent installation in Benidorm shows that not all AIS receivers perform the same. The picture below shows previous coverage using a 3rd party AIS.
They then upgraded to a Digital Yacht AIS receiver and the performance improvements are dramatic – an 8 fold increase in data received and over 4 times as many ships all from the same location and antenna. You’ll notice too how ATONs and AIS base stations are correctly decoded by all Digital Yacht receivers
You can also see the dramatic increase in data traffic in the graph below when the new receiver was turned on at 2:10pm. Digital Yacht – better AIS solutions.
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 169.254.1.1 to 192.168.1.1 fixed the problem.
The 169.254.1.1 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 169.254.1.1 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.
Despite our popular CLA1000 Class A transponder being predominately fitted to commercial ships by experienced electronic installers, an increasing number are being fitted to pleasure craft and are often installed by the boat’s owner or an installer who has never fitted a Class A transponder before.
Installation is pretty straight forward, but there are a number of steps and procedures to follow:-
Things do not always go to plan and with this in mind, we have released a Fault Finding Guide to help users, new to Class A transponders, work out what is wrong. To download a copy of our AIS Class A Transponder Fault Finding Guide, click here.
Today we had an interesting telephone call from a customer with one of our AIT3000 units that was not providing wireless data to his iPad. The unit had been working perfectly when installed earlier in the year, but on conducting some last minute system checks, prior to leaving for the Baltic, the customer found that the AIS data to his iPad appeared to be corrupted (see image above).
On seeing this screen shot, we immediately confirmed that the NMEA data was indeed corrupted as the majority of the characters were not your normal alpha-numeric ASCII dataset. Our first thought was that the unit had an internal fault but on further investigation we found that instead of trimming off and isolating the unused wires in the Power/Data cable, the wires had been tied back and taped up. Unfortunately the wires had now started to touch together with NMEA output wires touching NMEA Input wires resulting in the data corruption we had seen.
We asked the customer to isolate and trim back all of the wires and “voilà” the wireless data went back to normal and the iPad App could display the AIS and GPS data again. The customer was very relieved that his system was working again and we were reminded again how simple installation errors can cause the most unusual of fault symptoms.
Installation Tip – always trim back and isolate any unused wires.
This week we have been helping one of our dealers; Marine Electronic Installations (MEI) in Portsmouth, to find a solution to an interesting NMEA2000 problem with the latest range of Raymarine a, c and e Series Multi-Function Displays.
Most of these MFDs feature an internal GPS, a SeaTalkNG (NMEA2000) interface and an NMEA0183 interface. Under normal circumstances, if you connect one of our AIT2000 or AIT3000 transponders to a Raymarine MFD via SeaTalkNG (NMEA2000) the MFD will use its own internal GPS as the position source and receive the AIS target information from the transponder.
What MEI discovered, was that when a Raymarine SeaTalk 1 to SeaTalkNG converter (E22158) is fitted to the network, that the MFD stops using its internal GPS and tries to use a GPS source on the SeaTalkNG network. As our transponders are outputting the Rapid Update GPS PGNs on the NMEA2000 network, the Raymarine sees this as a GPS source and tries to use it but then reports an “AIS Position lost” alarm because the GNSS PGN that provides GPS status information is not being received.
This seems to be a unique problem to Raymarine and not one, so far, reported on other systems. For instance the latest Garmin plotters always default to using their own GPS and ignore the GPS data from the AIS transponder. Also it only occurs when this SeaTalk 1 to SeaTalkNG converter is in the system, although this is quite a popular accessory and used when boats have older ST50/ST50+/ST60/ST60+ instruments or autopilots with a SeatTalk 1 interface.
We have found two ways to fix this problem;
1) Connect the AIS Transponder to the Raymarine MFD via NMEA0183, which is fine for units that have an NMEA0183 input (all units except a6X and a7X )
2) Send a special configuration command to the AIT2000/AIT3000 transponder via the proAIS2 software that turns off the NMEA2000 GPS data
For more information on this configuration command please email firstname.lastname@example.org
Our AIT2000 and AIT3000 Class B transponders are supplied with a GPS antenna that has a 10m cable terminated in an FME connector (right hand connector in the above image).
These connectors are very slim, not much larger than the coax cable and are much easier to route through the boat. We also supply an FME to TNC adaptor for connecting the cable to the transponder (left hand connector in the above image).
Today we were reminded of the importance of ensuring this adaptor is firmly screwed on to the cable, when a US customer reported that their AIT2000 had stopped getting a GPS fix. After using the proAIS2 software to confirm that the GPS signals were very low, we asked the customer to check the GPS antenna connections to the AIT2000 and sure enough found that the FME connector had become loose and was no longer making a good connection.
A quick tighten of the FME connector in to the adaptor and the AIT2000 started to get a GPS fix again and the customer could continue their cruise.
The nut on the FME connector is 8mm (AF) and the TNC adaptor has two flat indents that are 9.5mm (AF). You can tighten the two connectors quite tightly but avoid using too much force which could damage the connector and cause a different set of problems. The image below shows the FME fully tightened in to the adaptor and there should be about a 1.5mm gap between the FME nut and the collar of the adaptor when properly tightened.
Our GV30 combo GPS and VHF antenna also uses FME connectors and is supplied with a TNC and BNC adaptor, which should also be tightened in the same way.