Suitable cable for rear view/reversing camera for caravan

[David]

We are about to become owners of an 8 metre long caravan.

It would be good to have decent rear view for normal driving, overtaking on dual carriageways, and of course reversing.

From the rear of the van to the front of the hitch is 8 metres (plus a bit more for negotiating corners etc,) and from the hitch to the dashboard is at least another 3 metres.

Allegedly that is a bit far for wireless to work reliably so I am considering a hard wired unit.

Next question is, what kind of wire to use?

There must be a minimum gauge to compensate for signal loss over distance; or perhaps using Ethernet style UTP?

Anyone with any experience of this?

I assume it is a specialised version of CCTV.

Cheers

Dave R

[Brian Gaff]

Depends on how you are doing it, analogue or digital. From the point of view of wireless, don't bother too prone to interference etc. Brian

[newshound]

I think wireless will be fine at that distance, admittedly the last one I did was on a horse trailer, but I also have a hand-held monitor and that would pick up at 20 metres.

If you are really worried you could run standard CCTV coax to a wireless transmitter at the front of a van. Can't see any reason not to stick with analogue and keep the price down.

[Tim+]

Motorhome forums are full of messages about the flakiness of wireless rear view camera. I wouldn't try wireless for 11 metres distance.

Tim

[Scott M]

You're over thinking it - 11m will be fine for composite over half-decent co-ax.

[Bill Wright]

If you do it with cable what sort of connector do you envisage at the tow hitch position? 75ohm BNC for video plus something to connect the

12V, inside a rubber shroud would be a possibility.

Re the 12V, you might think this an odd suggestion but I use metal bodied (NOT plastic) 180degree five pin DIN latching plug/flying socket for all that sort of 12V and 24V vehicle stuff. Viewed from the rear of the plug I connect the five pins as follows, going clockwise and with the pins occupying the top half of the circle: +, +, not used, -, -. I've found this to be an extremely reliable connection system. I've been using it on all my vehicles since 1970.

Bill

[Capitol]

CCTV cables work well. The problem with wireless is that some have very poor range. I have one that works over 10M and another that only does 3M.

[David]

Thanks to all so far.

12v is not a problem because the caravan already has plenty of 12v via the standard 13 pin plug/socket.

There is the option of using one spare plug pin (pin 12) but that would imply using standard automotive wire at least for the length of the leads between the front of the caravan and the car boot.

So perhaps using a 75 ohm BNC for the signal would be sensible.

How thick should the co-ax be? CT 100 style TV/satellite cable is quite chunky. Is there a smaller diameter which would be acceptable for a shorter run?

Cheers

Dave R

[David]

Additional from reading some of there also seems to be an option for twisted pair.

One suggested way is to have the video cable run into the boot where the boot lid meets the surround, relying on the sealing rubbers to allow the cable entry.

This is attractive in that I could have a permanent socket in the boot which would allow connection of the caravan camera or (in future) the addition of a camera on the rear of the car to be used when not towing (or when backing up to hitch up).

Thin and strong would be good for this.

It might also allow a connection inside the boot protected from the elements.

Cheers

Dave R

[Brian Reay]

If you look on Ebay you can find cable with screened cable/coax suitable for video and other wire for power etc all in one outer 'jacket', used for closed circuit tv.

The connection between the car and the caravan is another matter- at the tow bar. I doubt there are enough spare pins in the existing plugs/sockets, I can't recall. You could reduce the number needed by just, for example, 'piping' the video and picking up the power in the caravan- say from the ignition switched supply. Likewise, if you want to switch it when reversing etc., pick that up on the caravan side (assuming you have 13 pin or double plug electrics). If you are just 'piping' video, look for something like a small BNC connector pair you can slip a sleeve over to protect it and tuck it away, or fabricate a two piece shield from some heat shrink.

Tell your insurance company you have a camera, we got a discount on our motorhome insurance.

[Brian Reay]

RG174 is much smaller, maybe 3 or 4 mm in dia. It is 50 ohm but probably not an issue in this application.

[Bill Wright]

No, use 75 ohm cable. Why make potential problems? You can get miniature

75ohm coax. Google those three words. But the connectors can be a bit fiddly. I'd be using normal RG59 if it was me doing it.

Bill

[Bill Wright]

You can't run video through the towhitch socket. The interference would be horrendous. It has to be screened cable and connectors all the way.

Bill

[Capitol]

Yes, Use CCTV cables and connectors, very cheap, small size and they work.