Understanding the basics: In simple terms, the Flarm unit itself has a small computer inside it which sends and receives 3D position information. It knows where you are in 3D because of the built in GPS and antenna (sometimes has an external antenna) and it broadcasts this position through the Flarm Antenna to other Flarm equipped device. The Flarm Antenna is also used to pick up Flarm signals being sent out by other Flarm users and delivers this information to the Flarm where it decodes the signal of height and position. This information is then displayed on some form of display. The information sent is in a standard form and down a standard pin out cable, typically a flat 6 pin cable (sometimes referred to as a 6pin IGC cable). This is then plugged into your display device. (Some Flarm units have the screen built in but also have an auxiliary Flarm display or data output.) The Flarm display has some intelligence built into the circuit board and notifies or warns you of potential conflict if another Flarm target is in range.
Three basic areas of upgrades; Screens, Antenna’s and Connecting to other devices.
The more sophisticated displays use the same data stream but are able to interpret the data stream and display track, GPS height and GPS climb or sink rate on a larger LED display in colour. This is in addition to the standard warnings for awareness and potential conflict. This is useful for general awareness of where gliders are in your location. This is a great addition to safety but not a substitute! It could also be considered a competitive advantage in cross country events where now the adoption rate is almost 100%.
The good thing about the common standard data stream from any Flarm device is it is “standard” so you can plug in just about any Flarm display from any manufacturer retrospectively and/or in addition to your existing display. i.e. it is possible to have two or more displays on the same chain. (Separate power supplies may be required for some displays or more than two displays)
The choice of displays is growing but the ones we use are from LXNAV
As a basic rule of thumb, a more up market super sensitive antenna will be worse than a standard one if it is put in the wrong place! So location, location, location for your Flarm antenna is the most important thing. Key bits are; make sure as much of the antenna as possible can see the sky in front, above bellow and behind as well as to the sides. Keep the antenna away from other transmit and receive equipment such as radios, transponders and GPS antenna’s. Lastly, make sure it is upright!
Now given the constraints within a glider cockpit, it would seem the last place you would want to put a sensitive antenna so a bit of compromise is required. The most popular place for it seems to be protruding through or on top of the instrument panel. This gives a good view to the front, above, sides and a bit behind. Below is not good though. Certainly buried inside the instrument panel is not good particularly if your glider is made of Carbon or Carbon Kevlar like some of the modern gliders.
The best coverage seems to be when the antenna is mounted close to the DV panel away from the instrument panel on the inside of the canopy.
The other consideration here is the cable length, the shorter the better as for every meter of cable you lose 1dB of signal strength. Typically, the antenna’s come with too much cable and you end up trying to lose the spare somewhere. If you don’t have the capability of shortening the cable and making up a new end then try not to coil the cable but figure 8 the cable loosely and store it away from radios and other antennas.
So once you have found the best spot for the antenna and you still want more range, then there are a good choice of antenna’s to choose from and if you know the cable length required, we can usually shorten them for you for a small fee.
A note on stick antenna’s built into devices like the Swiss Flarm. It is possible to remove the stick antenna and connect an external cabled antenna to these devices as the connector is normaly a standard sma connection.