I'm just at the beginning of my journey with Zoneminder and cheap cams

Basically, old P3 800, 512MB ram, Bt878[1] from ebay for £8 and cheap cam from ebay for £10 connected to first channel from the card (but also tried others) using 10m cable (to the same cable there's another one which is the power feed for the cam).
Everything (after a bit of fight) working fine, with one exception.
The image, seems to be having some kind of interference.
Eg.

Now, the first thing I suspect is this power feed that is attached to the antenna cable that with which the camera is connected, but I'd just to check with you guys, whether this can be potentially source of the problems.
Any suggestions, much appreciated!
[1] 02:09.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)
Flags: bus master, medium devsel, latency 66, IRQ 18
Memory at 40400000 (32-bit, prefetchable)
Capabilities: [44] Vital Product Data <?>
Capabilities: [4c] Power Management version 2
Kernel driver in use: bttv
Kernel modules: bttv