Tag Archives: marine navigaton

Simple guide to AIS Receivers

AIS Receivers – Why do I want one? Which one do I need?


Why do I want one?

AIS, which stands for Automatic Identification System, is a convenience which is becoming a necessity.  As a part of the safety suite of your small vessel it cannot be overstated how useful having AIS can be.  Although not yet mandatory, it is a natural partner to GPS and other navigation aids to augment your perception of the water around you.  In increasingly crowded waters, it is easy to stray into shipping lanes, with AIS it will be that much easier to stay out of danger.


It comes in 2 main types: Class A, which is mandatory for ships over 300 tonnes and passenger vessels and Class B, which is optional for everybody else. Class B is what we manufacture and they also come in two flavours: Transponder and receiver-only.  We specialise in receivers for the leisure and coastal fishing market.  These will collect information on shipping around you but don’t transmit any information from you.

So, what do they do?


The principal purpose of AIS is to enable everyone on the water to avoid everyone else.  Which, when the weather is against you, can be difficult to say the least.  The Class A Transponders are required to transmit a considerable volume of information but it boils down to who they are, where they are, and how fast they are travelling.  Our leisure models take advantage of this to receive these signals and use them to plot who’s where in the environment around your boat.  This is not a replacement for looking out of the window, many smaller vessels may not have AIS transponders and will not be transmitting, but it will plot all the larger shipping and (hopefully) keep you out of its way.


Staying with the ‘thing of two’s’, receivers also come in two types; channel hopping and dual channel.  Transponders transmit on two frequencies; 161.975 MHz and 162.025 MHz. Channel-hopping uses a sophisticated algorithm to listen to both AIS channels alternately and then combines the information, dual channel listens to both channels simultaneously.  The main difference is that dual channel receivers process the information faster as they are picking up all of it at the same time, this allows for faster plotting.  Equally, with channel hopping, it is possible to miss some messages while the unit is listening to the other frequency.


AIS works on a VHF signal and often the best choice is to install a dedicated antenna separately to the radio antenna.  However, for various reasons this may not be possible or desirable so signal splitters are available, however, the sharing protocol means no AIS signals will be picked up whilst you are using the radio. It is not good practise to rely solely on WiFi  under any circumstances.

Which one do I need?


We currently manufacture five AIS receivers. Two are channel-hopping, three are dual channel, all have a range of 55 nautical miles (LOS), work with Windows, Mac and Linux Laptops, work with chartplotters, output NMEA-0183 messages at 38400 bps on USB, are powered by USB and calibrated to a sensitivity of at least -106dBm at 30%PER. All but one interwork with GPS and that one has in-built GPS.  Three have WiFi and can output NMEA-0183 messages on that and two have RS422 connection as well.  


That’s a lot of information to take in so here it is in chart form:


AIS Reciever ⇨ A021 A022 A023 A024 A026
Attributes ⇩
Channel Hopping
Dual channel
Sensitivity @30% PER -105dBm -106dBm[1] -105dBm -106dBm [1] -106dBm [1]
Range[2] 40nm 40nm 40nm 40nm 40nm
USB powered
USB data
USB NMEA-0183 output
Windows /Mac/Linux
Works with Chartplotters
Interworks with GPS GPS


[1] Next upgrade should increase this to -110dBm.

[2] Tested with a pushpit antenna mounted at masthead, 60’ above sea level.


The A021 is a dongle about the same size as a large memory stick, the A022 and 23 are around 2” across (5cm) and less than ½” tall (1cm approx) so all three can be slipped into a pocket and taken anywhere and connected in the field.  (Is it still a field if it is on water?)


The A024/26 are a little larger, but still very portable. All are straightforward to integrate into your systems.  All but the A021 come in sturdy aluminium enclosures and the A024/6 has fixing lugs for permanent positioning.  


The choice is yours! The very economical option of the A021 is a chance to dip a toe in the water for £41.99 (+P&P), more features are added as you go up the range and are priced accordingly but  if you already know you need the sophistication of the A026 it is also competitively priced at £106.79 (+P&P).


We sell worldwide and have satisfied customers from Southampton to San Francisco and we strive to provide customer service that helps our products stand out in the marketplace. We welcome feedback and suggestions from our customers so get in touch!


You can find more detailed information on our AIS Receivers at:

http://www.quark-elec.com/products/marine at the end of the product description there is a link which will take you to the Application Notes.  If you have questions please leave a comment on the forum – we check it regularly and it’s often the quickest way to get an answer:


Or join the community at Facebook or Twitter;


Here are some of the things people have said about us and our AIS Receivers:


Funny is that they want to be really involved with their product and would like feedback from users. There they learn from. (Translated by Google)


Frank on Scheepspraet Forum

The Netherlands


Fantastic product A026

Jan. 30, 2017

I stumbled across this product while searching for ways to get AIS into OpenCPN with my Raspberry Pi. Not only does this provide AIS, but also GPS and connects to. NMEA 183 and routes that on wirelessly! I can’t believe it’s all there for a phenomenal price.

Glen, Denmark


Excellent receiver

Feb. 26, 2017

Bought this unit at my first attempt of receiving AIS broadcasts. I was on the lookout for a dedicated dual channel AIS receiver of good quality and reasonable cost. I was not disappointed. Excellent service and fast delivery. The unit works perfectly.

Alan, USA


Great product, works fine, excellent experience!

Feb. 20, 2017

Great product, works fine, excellent experience, we see important ships information and at moment works very well.

Shipping with no delay and client support works great.

Thanks guys.

Miguel, Portugal


Fantastic receiver. Almost as good as shipboard.

Nov. 16, 2016

I was so surprised at its size, especially for a dual channel receiver. The sensitivity and selectivity are excellent. Channel selection is automatic, no operator intervention required, it is truly plug and play. The performance of this receiver makes it worth at least 3 times the price.



Tampa Bay, FL



AIS receiver QK-A023

Jan. 13, 2017

I am absolutely satisfied with the QK-A023 so far.

It was easy to install and to integrate into OpenCPN . Both connections, USB and Wireless, worked seamless and without any problems.

I have only tested the receiver at home which is a few kilometer away from the next ships but even with a home brew VHF emergency antenna the reception was brilliant. I could see every ship that was announced by marinetraffic.com. I am looking forward for the new sailing season to use the device on my boat.


Brilliant product!

Lars, Germany

You can read more reviews at https://www.tindie.com/stores/Quarkelec/reviews/