Software app:

The FPOD app (FPOD.exe) carries out objective automated data analysis to find click trains in the data and identify those produced by dolphins, porpoises and all echo-locating cetaceans except sperm whales. It also provides fast display and export of data and enables users to analyze and compare C-POD and F-POD data as well as change C-POD and F-POD settings. Provided free, with free upgrades. The app and F-POD Software Guide can be downloaded here.

Working depth:

At least 100 metres. A single POD has been tested to destruction and failed at 220 metres.
DeepF-POD: At least 2 km.

Autonomous operation time:

Operation time is affected by battery quality/capacity and deployment noise levels. The F-POD has automated adaptation to noise so that it does not often max out even in severe conditions.

Alkaline D-cells: Maximum running times approximately 200 days. With good quality, high capacity D-cells, more than 4 months can be expected.

Lithium D-cells: With approximately twice the capacity of alkaline cells, these have the potential to enable longer deployment times.

F-PODs can be set to log 1 minute in 2 or 5 or 10 minutes to further extend deployment time. The F-POD has a real-time clock, so you can set the F-POD's start time, making it is feasible to deploy several F-PODs and set them to switch on consecutively in order to obtain a very long continuous data set from one deployment. This is called "daisy chaining".

Housing:

F-POD: Polypropylene. DeepF-POD: Aluminium.

Dimensions:

F-POD: Length: 710 mm. Diameter: 90 mm. DeepF-POD: Length: 710 mm. Diameter: 100 mm

Weight:

F-POD: 2.35 kg without batteries. DeepF-POD: 7.15 kg without batteries.

Buoyancy:

F-POD: Approximately +0.7 kg with alkaline batteries and +1.2 kg with lithium batteries. This makes F-PODs self-orientating and increases the chance of recovery if the mooring fails. A web link engraved on the outside has enabled over 150 PODs to be returned to their owners by people who have found them on sea shores, sometimes more than 2,500 km from home. DeepF-POD: -3.1 kg, not buoyant.

Mooring:

F-POD: 3 x 10 mm holes in the lid. DeepF-POD: 1 x 12 mm hole in the lid.

Hydrophone:

Improved hydrophone with less Z-plane variation. 20 kHz to 160 kHz omni-directional in a large-diameter housing to reduce surface noise. The transducer mounting and housing design gives high resistance to impact damage.

Memory:

Removable 32 GB micro SD card. Two SD cards are supplied with each F-POD. Any blank micro SD card up to 32 GB can be used.

Batteries:

Battery packs hold 10 D-cells. The battery housing is sprung to reduce battery damage from end impacts.

Detection range:

Maximum detection range for porpoises is approximately 400 metres. Dolphins may be detected at >1 km.

Standardisation:

See standardisation and calibration.

Click selection:

Digital time domain waveform analysis, using duration (5μs resolution), frequency, amplitude, number of cycles, bandwidth, amplitude profile, frequency profile and Narrow Band High Frequency Index, to select possible cetacean clicks in the range 20-160 kHz. On-board train detection selects clicks in trains so that some representative full waveforms can be saved.

Cetacean detection:

Coherent click trains are extracted and classified by the KERNOF classifier. This classifier is a fixed component of the process to give long term uniformity of performance.

Species classification:

Porpoises and other narrow-band high frequency (NBHF) species can be distinguished from broadband species. Some discrimination of groups of species within the broadband species may become possible when enough data is available. Every species tested has given good detection performance – see Species detection.

Sonars:

Runs two independent sonar detectors that detect and filter out boat sonars. A record is kept of sonar detections.

Settings:

The default settings cover all species and most environments. In locations with high levels of ambient noise, which are usually due to substrate transport by currents, standard low sensitivity settings may be required.

Angle sensing:

The angle-from-vertical is recorded each minute, enabling the user to check after deployment that the F-POD was deployed in a vertical position, and giving information on currents. A range of angles at which the POD will log can be set. This allows the F-PODs to be set up well in advance and transported in a horizontal attitude saving power and memory.

Temperature sensing:

Temperature is recorded each minute.

Maintenance:

The external surfaces of the F-POD are simple and tough allowing robust methods of removing biofouling. The lids use a dual O-ring design with grease-free lubricants and these have proved highly reliable.