discussion / Biologging  / 24 January 2023

Field testing of a radio telemetry system to be deployed in the sea.

Hello everyone

What kind of tests do you put aquatic tags through to get them field ready? 

Currently, we are testing a radio telemetry system. We are leaving the tags at 20 metres and 40 metres for a day to see if they can withstand sustained pressure. We are also doing some range and detection tests as well.

Curious about what you did to ensure an operational tag.




Hi Hari,

A simple test we do is pump the unit up slightly (maybe 1 psi), and check for bubbles.  It's like fixing a flat on a bicycle.  The positive internal pressure opens up and exposes any questionable seals.  Most of the leakage problems tend to be of the shallow water variety, which this test finds.  Deep water leaks are more rare, since the pressure tends to close up any cracks.

Otherwise the SOP is to lightly grease all O-rings and seals, and assemble the unit in the lab to prevent sand etc. from sticking to the greasy O-rings.


Is it possible to remove the compressible air from your design further? One option is to fill the cavities with a dielectric fluid such as mineral oil. Another option is to have a non-rigid shell, or a section of membrane that can expand or compress depending on depth/pressure. 


While googling this I came across a nice open source project from South Australia incorporating both of these methods into an underwater camera design. They might have more ideas and experiences to share.

Abhijit and Hari joined us at our Variety Hour show to talk in more detail about this project - check it out to learn more about how it's progressing. 

Not sure exactly how your telemetry will be deployed, but if it's going to be attached to an animal in a relatively non-invasive way, you might check with zoos or aquariums that have similar species. 

I worked in that industry for a long time and we tested telemetry for seals, sea lions, polar bears and elephants. There might have been more, but that's all I can think of off the top of my head. This can help improve attachment methods and test how tough the animals will be on the equipment.