Most folks recommend re-doing the "Park cable" inlet however I do not, In my coach that is around 50 feet of RG-59.. Very cheap RG-59, It's worth about 150 feet or more of quality RG-6
I recommend the following
First, at the receiver, install a simple A/B switch, The RCA VH71 is a very good switch for this (One whole dollar plus S&H at the Google store just now)
A- Goes to the roof (Existing cable)
B: to either a connector in the Basement, or a Bulkhead (Throughwall) connector down Below for the portable (Tripod) antenna)
Of course the remaining terminal on the swich goes to the LNB in on the receiver.. USE RG-6 Cable all the way.
Now, to switch from roof to Ground mount...
1b:First hook up ground mount,, THEN Switch the switch.
2:If using DIRECTV.. Then reset the reciver,
3:Then point the antenna
4:Then, If using DISHNETWORK do a Check Switch.
5:Then enjoy TV
To switch back to the roof mount,
1A:First switch the switch, then unhook and stow the ground mount, Move out into the clear
2A: Go to #2 above.
