Dumb electronics question - aerial extension for wireless

[David]

I have a wireless battery powered camera on the back of my caravan.

The signal is not 100% and as far as I can tell it relies on reflections to get from the back of the caravan to the front of the car (just guessing why it sometimes drops out, behaviour strongly influenced by the angle of the aerial and direction).

The aerial appears to be the standard type you get on WiFi equipment - it will unscrew.

One option is to move the aerial upwards and/or forwards to provide a clearer and shorter signal path> For this I would need an extension lead.

seems to provide various lengths of extension.

I would need some king of base to fix the aerial to at the other end, but before I delve into that, how do I work out if using such an extension cable will improve the signal?

Cheers

Dave R

[Theo]

What frequency does the camera use?

Theo

[Graham.]

Unfortunately you have told us very little about the equipment you have.

For example if the receiver is a separate box, that connects to a TV set, rather than built into a dedicated monitor, then it might make sense to locate the receiver box towards the rear of the van and extend the video (and audio if appropriate) cables to the TV.

[Chris Green]

Is there not a wired (i.e. Cat5 cable into RJ-45 socket) option on the camera? If there is then I'd use that in preference to WiFi any day.

If WiFi is the only option then an extension cable *may* help but they often lose almost as much signal as the different position gains.

Where is the 'other end'?

[Bill Wright]

2.4GHz.

Bill

[David]

The camera on the back of the caravan is in a sealed waterproof (I hope) casing. On/off switch, charging point for the battery, and aerial on top.

The screen mounts over the driver's mirror top centre of the windscreen. It is powered from a 12v socket.

The two units come as a pair, allegedly they have to be paired to work together and this takes place during assembly.

Cheers

Dave R

[gopalansampath]

It might be due to interference from hoardes of devices on this frequency ranging from babay monitors to security cameras to MicroW ovens etc., I f one desires reliable camera feed only way is to go "wired"

[Brian Gaff]

And where is the receiving aerial, which will probably be both a transmit and receive one as most wifi is two direction.

One might have thought they could in some way piggy back a signal onto its power leads to the battery circuit. Still I guess its more flexible if its wireless in this regard, given all the non standard standards about at the moment. I'd have thought if the caravan is not metal, then if you could get the aerial in the car outside at the back then it would work better. Brian

[David]

All constrained by the design.

Rear camera is completely self contained, including rechargeable battery. Therefore I can't see using the internal battery leads as an aerial would be more effective than an external aerial.

Screen at the front is self contained and sits over the rear view mirror, but powered by a lead to a 12v socket. Possible to use that lead as an aerial (I have no idea if they do) but there is no obvious external aerial. I assume that it is internal in the way that mobile phones have internal WiFi aerials. Or my latest compact camera, for that matter.

So no option to get the aerial out the back of the car as there is no external aerial connection to the screen. This would also probably involve some hackery to the car.

I suspect that the smoked windows on the car may also resist signals a bit (can't remember where I read this).

Which is why I am asking for potential ways to improve the signal path.

The caravan is not metal, but there is an awful lot of stuff inside including a complete rear wash room across the back. This is why I was keen for a wireless solution because I don't fancy anyone trying to get through the back wall of the caravan and through the washroom to run the cables.

Almost brand new caravan and I don't want more holes in it than absolutely necessary.

Cheers

Dave R

[Harry Bloomfield]

Communication will probably one way. Camera only transmits the picture, screen only receives the signal...

You might try stripping the screen from some small coax, then a few turns of few turns of the core wire around the screen, the coax to maybe the outside via a window or a sunroof, then remove the screen of the coax for a few inches to form an antenna.

Something similar at the camera end.

[Chris Green]

Not so if it's a WiFi connection using TCP/IP. There has to be a 'conversation' between the ends to establish communication.

[David]

I doubt that it is using WiFi but I will use my phone as a scanner to check.

If it was WiFi then a repeater might help. However I am assuming that it is just broadcasting, but with some kinds of encryption to prevent trampling over other signals or picking up other signals.

Cheers

Dave R

[Chris Green]

But what's at the other end? I don't think you've explained this yet really. Is it just a dedicated camera and display system or is it a 'web camera' and a simple server to display?

[David]

Battery powered (self contained) camera at the back of the caravan.

Cigar socket powered screen which fits over the central rear view mirror in the car.

Both self contained units.

I think some posters have been a little enthusiastic in their snippery.

Cheers

Dave R

[Chris Green]

... and does anything say how they're supposed to talk to each other?

Yes, probably.

[David]

Wireless, probably (almost certainly) 2.4 GHz (see Bill Wright's early reply).

Cheers

Dave R

[Chris Green]

Er, yes, it could hardly be anything else could it! There still has to be some sort of protocol that both ends undertstand for 'wireless' to actually do anything.

It could be WiFi (11b/g/n etc.), it could be Bluetooth, or it could be something else but there must be some sort of set of rules it works by.

I'd expect the 'user manual' (or sheet of paper) to say what sort of protocol is being used.

[David]

Ah, bless. :-)

The sweet innocence of youth.........

Unfortunately, no.

Still haven't snooped, but assuming some kind of proprietary broadcast protocol using security by obscurity.

Cheers

Dave R

[Chris Green]

Security? What for?

Though I agree the 'user manual' may not be all that forthcoming, that's why it's in quotes.

'Youth', the nicest thing anyone has said for years! :-)

[David]

The security is to pair the transmitter and receiver up and ignore other broadcast sources (and also not to trample over other receivers, hopefully)

There are many tales of wireless rear view cameras which suddenly start displaying the output of the number recognition cameras at petrol stations.

Cheers

Dave R