Finding the right aircraft with a functional telemetry tracking system and a knowledgeable pilot is an essential starting point. While cost is important, in the long run researchers will find it more economical to contract with vendors with aircraft specifically configured to meet the needs of the tracking protocol. Aerial wildlife tracking systems are often thrown together in a make-shift manner. These simple configurations are pressed into service and are too often geared toward aircraft flexibility for the vendor and don't provide the same level of efficiency as a dedicated telemetry aircraft. A properly equipped aircraft and a competent pilot save not only time and funding, but enable the researcher to get the highest-quality data for which they are looking. Dedicated telemetry aircraft are permanently or semi-permanently configured with sophisticated combinations of antennas and audio distribution systems.
Forward facing Yagi and side facing “H” antennae
There are several antenna configurations available to achieve signal locations. Most configurations are relatively simple systems representing some compromise between the aircraft flexibility and an antenna combination functional for the mission's purpose. The most common of these configurations consist of a pair of side facing Yagi or “H” antenna selectable using a 2-way in-aircraft switch box. Others may have a single rotatable antenna mounted on the belly of the aircraft that a passenger observer controls from the cabin. If a mission's sole purpose is to determine a species' status, a simple Omni directional antenna may be all that is required.
FINDING YOUR SIGNAL
Obtaining a signal location can be broken down into two distinct phases, 'initial reception' and 'final location'. For initial signal reception, Owyhee Air relies primarily on a forward facing 4 element Yagi antenna. While this forward facing Yagi configuration typically has exceptional reception, downward and sideways reception is occasionally limited in rugged terrain. To compensate for this, Owyhee Air employs “H” antennae used in conjunction with the Yagi The benefits of a forward facing Yagi antenna are three-fold. First, the ability to fly directly towards the signal using the Yagi eliminates much of the search pattern required using only side facing antennae. Secondly, since the greatest reception capability of the Yagi antenna is in the same plane as the aircraft heading, earlier signal reception is achieved while flying toward suitable habitat or previously known species positions. Finally, the “signal null” found near the 0 degree and 180 degree positions of side facing antennae may give the operator a false “lost signal” indication. Conversely, while flying toward the signal using the forward facing Yagi, no signal reception from the side facing antennae assures the operator that the aircraft is headed directly at the signal. When using a forward facing Yagi antenna, exclusive use of side facing antennae typically does not occur until final species positioning or visual sightings are to be recorded.
Audio distribution systems range from rudimentary to sophisticated. Dedicated telemetry aircraft typically utilize a permanently mounted antenna coax cable, switch box(es) capable of selecting a single or multiple antennae, and a telemetry receiver audio that can be heard over the aircraft intercom system.
Enough can’t be said about communication and team work between pilot and researcher in maximizing efficiency and accuracy while flying (when researcher is a flight passenger) or in pre-flight preparations.
In-flight, communication between the pilot and researcher is accomplished by means of the aircraft intercom system.
* In an optimal telemetry aircraft setup, the telemetry receivers themselves are plugged into permanently mounted audio receptacles, allowing the receiver audio to be heard over the aircraft intercom system by both pilot and researcher.
"Choosing the right aircraft, equipment, and pilot is perhaps the most pivotal step in ensuring the accuracy of researchers' studies." --John Romero pilot, OAR owner