Why birds are tough targets

Plus, tips for extending your instrument system

Why identifying birds is much harder than finding fish
What you can do to improve your chances
Developing and extending your system

Identifying specific birds, either alone or in flocks in order to search out shoals of fish is a technique that is as old as fishing itself. Yet the development of more sophisticated radar has in theory at least, made it easier to spot fishing grounds that are on the horizon or beyond.

Birdfinder Radar

Using radar to identify birds is a much talked about technique yet as Simrad® Product Director Laurie Bates explains, it is not quite as simple as that.

“Fundamentally, the tricky thing about birds is that they are a very weak target,” he says, “There are a number of issues with identifying birds that makes it difficult.

“The first is that birds vary in size around the world. You talk to one fisherman in eastern Australia who is looking for a certain type of bird and it’s completely different to the guy in Florida that’s looking for Frigates.

“Do they live in a big flock or are they flying as a group of two or three birds? Or perhaps they are birds that sit on the surface of the water and only fly two or three feet above the surface. If so, they’re in amongst the sea clutter which makes them difficult to identify on the radar.

“Detection is the first hurdle so one of the key suggestions we make for people who want to use their radars for this is that you need more power on target to stand the best chance of detecting birds. This means buying the biggest radar you can install on your boat. The rationale is simple, the bigger the antenna, the more antenna gain you have.

“But even then, if the birds are close to, or on the water’s surface and it’s a choppy day there will be a lot of sea clutter and they will be very hard, if not impossible to pick out, so you have to be realistic about your chances, even with a large radar.

“Having said that, we do include a bird mode in our radars which helps by optimising a number of tuning parameters so that you don’t have to tune the radar manually. Parameters like, slowing the antenna down and performing certain tuning functions in order to try and get maximum energy on a small target to give you the best chance of detection.

“But overall, while radar can help in certain conditions, it is important to realise that birds are not going to paint up on your screen like a really nice solid contact. They are going to look like a weaker contact. It’s not going to be like looking at neat fish arches on your sonar.”

George Poveromo puts Simrad® Halo® Bird Mode to the test.

Instrument system

Aside from the specific task of identifying birds, another popular topic is how best to develop and extend an existing instrument system.

“If you’re happy with your existing displays like your chart plotter and sounder and don’t want to change these there is always the option of adding another display,” says Laurie. “Naturally, this will depend on whether you have got space, but some people find that all they need is a small, seven inch display that they use as a dedicated radar screen.’’

Any of our 7 inch, Simrad® GO or NSS units can be used as a radar display.

Alternatively we have dedicated Simrad® radar displays that are not multifunction displays.

System Integration

When it comes to integrating the network, it’s a simple task.

“It’s easy, you just go into the menu and select, ‘auto select’,” explains Navico® Product Expert Craig McMIllan. “That will search the NMEA 2000® network and use all of your sensors such as: GPS, compass, boat speed, wind speed to select the various sources of data that the system needs.

“Radar data is shared over multiple screens via an Ethernet connection. In these situations, we like to include an Ethernet switch, or Navico Network Expansion Port (NEP) rather than daisy chaining, so that if you turn off one of the screens, then the other screens still have access to sonar, radar and charting data. The Ethernet switching handles it seamlessly.

“What we don’t encourage is daisy chaining the devices because if you turn off one of those units then it is no longer sharing the data with other items such as the sonar, radar or chart plotter.

“An Ethernet system that is based on a hub allows you to build up redundancy in the background and because it is feeding information to all of your MFDs (Multi Function Displays), you can configure your boat how you like.

“Plus, in the event that you have a problem with say, your chart plotter, your chart is still available on any one of the other displays as well.”.

Laurie Bates

BE MSc CENG MIET

Laurie’s involvement in electronics has spanned his entire career. After studying electronic and electrical engineering at Auckland University he spent 20 years in the NZ Navy and gained an MSc in Explosive and Ordnance Engineering at Cranfield University (UK). With a wealth of specialist radar knowledge and having worked in the defence industry he joined Navico where he is now Product Director at Simrad Yachting.

Craig McMillan

PRODUCT EXPERT

After a career in avionics in the New Zealand Airforce Craig was a distributor for Simrad® and B&G® products for 20 years before joining Navico as Product Expert, a role that he has held for the last six years.