I have a Swann DVR security system.  There are 8 channels and the cameras are hard wired using BCN cables.  There is no in-built provision for a Wifi camera.

 

At the moment I have some spare channels and a need for a camera in a hard to get to location.  The standard cables are 18m and not quite long enough to reach where I want the additional camera - I can probably extend the cables but I wondered if there is another option?

 

This is a long shot but does anyone know of any sort of receiver that I could plug into one of the spare channels that would pick up the signal from a Wifi camera?

I think you will find it easier to run a longer BNC cable to the camera location.   Even if you can convert a BNC camera signal to wireless, and back again, how are you going to power the camera?  You could be lucky and it's now a power point, but probably not.

 

30m BNC cable from Lazada only 119 baht.

 

https://www.lazada.co.th/products/bnc-bncdc-30-video-bnc-cable-for-cctv-30m-i590270646-s1100882896.html?spm=a2o4m.searchlist.list.5.2f6918468ZQhl3&search=1