Voltage on satellite cable down sheild

[kouroshfarsad]

Voltage on satellite dishes cable shield
What is the secret of voltage on sat dishes cable shield?

 

[kanewolf]

I think the voltage is on the center conductor relative to the shield. This allows the shield to be grounded. The center conductor is isolated by the rf insulation for the 20 or so VDC. The amplifier on the dish uses the voltage to power itself and (used to) for RF polarity switching.