base scanner antenna mount/coax?

[wingnut7zero5]

I am going to setup my scanner for base use at home and have some coax/ mounting questions.

The house where I am living has an old Sat dish. I am going to remove the dish from it's mounting arm. I am going make a mount to attach a discone antenna to the mounting arm. I want to use the existing 75 ohm coax run for a few reasons: Exsisting coax is already run and exsisting coax has grounding wire(not currently hooked to ground) for purposes of lighting protection. My questions are:
1. Will the impeadance of the coax cause performance issues compared to 50 ohm coax?
2. If the coax is usable, where should I connect the ground wire at the scanner end? Should I just wire it to the ground of a 3 prong ac power plug and plug it into the wall or find another ground?

Does this sound like a good combination to try or am I just off my rocker? To start it will only cost me the antenna and a couple of connectors

 

[andrewccm]

Depends on how long the cable is more than anything from what I understand. If it's less than 50ft or so, you may not notice much difference over a 50ohm cable. That said, I have LMR400 run to my attic and notice a slight difference. The cable is 75ft and is actually way too long. I will probably replace it with something around 30-40ft instead at some point.