Video signal DC level adjustment

If I receive a video signal thru wire that is ~500 ft long, I'll be concerned about its DC level. Is it practical to capacitively couple the signal to my video amplifier or will an attenuation factor of the caps degrade the signal. I'm too lazy to do the calcs I suppose but also I'm uncertain of signal freq.

 

Power to camera will be in same cable but not same wire as video signal wire.Video signal typically - & + from camera out. Typically power ground and - side of signal tied together at camera. Seems like at amp I could tie - side of signal to power ground but in last iteration this wasn't done. At the moment I don't recall why. What may be my gnd level at camera may drift some over a 500 foot run of wire, particularly if on a spool, say 250' straight line and 250' spooled. It takes very little voltage drift to start chopping one side of signal resulting in screen blackout or whiteout.

 

Coax is too rigid. Last prototype used 5 or 6 conductor (twisted pairs) shielded cable. Worked nicely. For whatever reason (I will guess DC level drift ) monitor had a tendency to white out. The famous microsoft fix (cycle power) would almost always bring back image.

 

Surprisingly, baluns did not seem to be necessary. Good resolution until white out.