Hey everyone,
I'm new to the site and relatively new to the field of RF. I'm a wildlife biologist and the majority of my work deals with radio tracking of animals. Until now, the majority of my work has been done with terrestrial animals working with transmitters that use 150-164 MHz range. However, I'm starting to transition to more aquatic animals---specifically, animals that live in salt water.
I'm interesting in continuing to use radio tracking to monitor these movement patterns, but due to signal attenuation in salt water at these high frequencies it may be nearly impossible to do. From what I've read, I understand that the lower the frequency, the better it will transmit through salt water. Specifically, would it be feasible to build a transmitter that 1) works the VLF range 3-30 KHz and can transmit signal at least 2-3 kM to be picked up by a receiver and antenna on land, and 2) how exactly does the antenna on the transmitter send signal---i.e. does signal emit from the very end of the antenna, or along the entire length?
Meaning, in theory if there is a fish one-foot underwater that has an antenna attached to it that is 12 inches long, 2 inches of that antenna will be above the water surface---will this then transmit impeccably even if it's in the VHF range of around 150 MHz or will the saltwater around the majority of the transmitter whip antenna attenuate the signal?
Thanks for any help! If the answers to these problems are obvious please excuse me---like I said I'm a biologist by trade---not a RF guy or an engineer.
-David
I'm new to the site and relatively new to the field of RF. I'm a wildlife biologist and the majority of my work deals with radio tracking of animals. Until now, the majority of my work has been done with terrestrial animals working with transmitters that use 150-164 MHz range. However, I'm starting to transition to more aquatic animals---specifically, animals that live in salt water.
I'm interesting in continuing to use radio tracking to monitor these movement patterns, but due to signal attenuation in salt water at these high frequencies it may be nearly impossible to do. From what I've read, I understand that the lower the frequency, the better it will transmit through salt water. Specifically, would it be feasible to build a transmitter that 1) works the VLF range 3-30 KHz and can transmit signal at least 2-3 kM to be picked up by a receiver and antenna on land, and 2) how exactly does the antenna on the transmitter send signal---i.e. does signal emit from the very end of the antenna, or along the entire length?
Meaning, in theory if there is a fish one-foot underwater that has an antenna attached to it that is 12 inches long, 2 inches of that antenna will be above the water surface---will this then transmit impeccably even if it's in the VHF range of around 150 MHz or will the saltwater around the majority of the transmitter whip antenna attenuate the signal?
Thanks for any help! If the answers to these problems are obvious please excuse me---like I said I'm a biologist by trade---not a RF guy or an engineer.
-David