Don’t know what sort of coax cable you buy but I think you would find the PVC used on quality cable (Belden, Huber-Suhner or the like) the PVC cladding is very adequate. There are many installations that have been operating for many years with cables exposed to the Elements and have been OK for 10, 15, 20 years or even more. TV transmitter installations are usually aluminium sheathed and range in size (expressed in inches) from 1/2" through 7/8", 1 5/8" 3 1/8" up to 4 1/2" that I know of. Some have a PVC sheath over the aluminium and have been in situ for many years with no ill effects.
Cheers Bob
The TV cables are usually F & G (German) or Andrews (American). Andrews is (or used to be) pretty big on the Australian scene supplying all sorts of cables and connectors for different uses.
Perhaps the simplest way would be to use an off the shelf USB fibre optic cable, and water proof it.
Yeah, good PVC is fairly tough and flexible. Cheap PVC insulation is often fairly hard or thin, which means any small crack or nick which might be perfectly survivable in air would spell disaster when submerged.
If it’s only going in the water for short periods, like flying an RC plane, then normal wiring is probably fine. If it’s sitting out there for extended periods in the sun and weather you’d definitely want proper marine grade cabling - especially with any brittling that may occur.
Edit: Found this great summary of wiring insulations:
If you hit the reply button when responding to someone they’ll get a notification when you post, Oliver may not have seen your last message.
The advantage of this forum though is that we can have a 1-to-many discussion, that others can use as a resource later if they have a similar project. Taking things to a private message is recommended for anything involving personal or identifying information, but for brainstorming ideas it’s best to keep it all in the thread.
Hey Oliver I am keen to explore the idea of fiber to the surface and wifi from the surface to the screen. I am keen to get an order for the bits I need.
Hi Oliver
Serious “Marine grade” cable us usually lead sheathed or SWA (Steel Wire Armoured).
I stress here the word “serious”, stuff meant to survive many many years.
Bit exotic for the home brew project methinks.
Cheers Bob
Serious “Marine grade” cable us usually lead sheathed or SWA (Steel Wire Armoured).
I don’t mean anything inudstrial like undersea cable, cargo ship or oil rig stuff, just ordinary marine grade you can get from any hardware store.
It has a higher strand count, it’s fully tinned, and it’s got extra flexible insulation that’s more resilient to various environmental factors (chemical and UV exposure mainly).
My biggest concern is if the pi has enough punch to end the signal up the cable?
My advice is try it and see, worry about fixing issues with signal if you need to. If this is just a prototype and it’s only going to be in the water for short durations, start with a standard USB cable, and switch to something better if necessary. Fiber optic USB cables are at least $100 each, whereas standard USB cables can be had very cheaply.
You can probably do a quick test by chucking a cable in your bath tub, or kitchen sink. As long as the whole cable is submerged it should be a fair approximation.
Hi Oliver
Yes I did mean “serious” like what you would find on a ship or larger vessels where damage can easily occur.
Re that video, I honestly have never seen cable advertised like that as if “Marine Grade” was something super special. Looks to me like a bit of shrewd marketing. My not noticing might be because I have never looked, I don’t have a boat so tend to just walk past boat shops unless I want something special in the stainless department.
We (by "We I mean my employer) tended to purchase cable and wire as an item which would do the job or met laid down specifications. Never knew if it was “marine grade” or not and didn’t much care. We used Hartland quite often as if something out of the ordinary was required like double screening which may not be a stock line for a particular size they would make it for us by just putting an extra screen on during a production run. I personally go for tinned wire unless I have no other alternative. I still have a bit of Kynar wire left over which is silver plated. As a general rule I like 0.2mm stranding but if I need more flexibility I try for 0.1mm which are both common. If greater flexibility or temperature rating needed I would look at silicon sheathed wire.
The most super flexible cable I ever came across was in the mid 90’s and was made by Raychem, USA. This cable had 5 (I think) wires inside and used for helicopter coms while on the helipad on a ship. This was designed to just “flop” onto the deck and not get blown around by the Rotor wind. Worked very well apparently BUT the cost. I believe US$76 per FOOT. Not really your average hobbyist wire and that was 25 years ago. If you are wondering why a helicopter would have a cable plugged in if it had to leave in a hurry. The connector is a special quick release type (also cost mega bucks) connected to the deck with a small chain, If the aircraft leaves in a hurry the chain operates the quick release mechanism and the connector falls out.
Cheers Bob
