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4

Here is some useful scholarly information about the signal attenuation (in dB) of EM waves through freshwater at various frequencies and depths. You will find a formula that you can use. You will also need to know the antenna gains, transmitter power levels, and the receiver sensitivity at the bandwidth. RF Path and Absorption Loss Estimation for Underwater ...


3

SSTV could be an interesting answer here. Bandwidth requirement is about 30 KHz to reach your goal of 1 frame per second AND it's proven tech on HF bands... though you'll need to multiplex the video feed yourself (or another strategy) to use 30 KHz instead of the typical 3 KHz. This may be a great opportunity to use a loopstick antenna. Yes for transmitting. ...


2

Any antenna under water is creates a far more difficult problem than that of the main focus of the school project. I would put a WiFi transmitter (ESP32, et.al., inexpensive loss if drowned) on a float above the submersible, and run a fiber optic cable to transfer image files from the FPV camera (connected to say an inexpensive Raspberry Pi Zero that won't ...


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