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BlueROV without Phantom-X

@bluerobotics3 @bluerobotics

I have changed the raspberry pi along with other components and I have no space left for fathom-x interface. I have two questions

  • What are the specific benefits of using fathom-x instead of a regular ethernet connection?

  • Would there be any side effects if I remove the fathom-x interface and just connect to the companion computer using ethernet (8 cables from tether)?


An Ethernet channel is the complete end-to-end connection of a cable run from a router/switch to your ROV. Suffice it to say that from powered-device to powered-device the limit is 328 feet.

If you don’t intend to dive deeper than that, running 8 wires instead of two may work for you. Keep in mind you will use up some of that footage going sideways as well as down. If any water gets inside the Cat5 ethernet cable, it will have to be replaced. If any one of the 8 wires breaks, again, the whole cable will have to be replaced.

Bulk ethernet cable is meant to be installed from one location to another then never move again. For example, ran from the reception area computer to the servers in a back room…fished through walls and across ceiling joists, but once done it never gets twisted around or moved. So it is always composed of 8 solid copper wires (if you avoid the cheapo copper-coated aluminum junk), rather than the stranded (more flexible) cables meant to connect two close computers together temporarily. So it isn’t meant to be rolled up, unrolled off the spool every time you dive the ROV, submerged in water, etc. It will work for a few dives then you may have problems.

With serial communication over two wires, you can use off the shelf stranded speaker cable, and the RS485 protocol is good for about 4000 feet.

Try putting the FathomX into another WTC?

Thanks for the reply. I will try to make space for Phantom X or contain it in a different WTC.

@Oddmar I have one simple clarification to ask. If I use fathom tether (which has 8 wires) for simple ethernet to the ethernet connection, is the range 328 feet? I could just use a female connector like this
Female panel mount connector, solder, Series 770 | binder USA | binder USA to connect to ethernet.

If so, I will need more range so will try to fit fathom-X somewhere.

I mean 8 wires used for ethernet, like a regular Cat5 cable. I don’t have a fathom tether so i don’t know what wires they use for what, but i’m pretty sure the fathomX only uses two wires for comms.

@Oddmar yes they use only two wires. I am not sure if using fathom tether with 8 wires will solve my issue or not?

If you still do not want to use Fathom X board that use 2 wires (1 pair),
You could also go for standard 100MBit on 4 wires (2 pairs), that is a little bit more stable then 1 GBit
Going 100MBit has still a theoretic 100 meters max range, but that is possible to puch that a bit

If you use the standard issue tether for anything within the 300+ ft range I’d have thought terminating in an Ethernet plug at each end would be more robust, less to go wrong, but everyone seems against the idea…what am I missing? Confudled