No Signal thru long coax on HD7000R

[patrick_here]

Hello,
I'm having trouble getting signal from my newly-installed Winegard HD7000R. Here are the facts:
1. I live in the San Francisco Bay Area (Redwood City); the reception map for my address shows that I can get 20 stations in the "Strong" category.
2. I connected some rabbit ears directly to the TV and confirm that I can get many channels even with the rabbit ears inside my house. My rabbit ears are Amplified.
3. I connected the Rabbit ears to the coax at the Comcast Cable service entry (wich adds a F-to-F connector and about 20' more of cable) and again I get excellent reception.
4. I connected the HD7000R directly to the TV right in my Living Room through a 5' Coax Cable and confirmed that it works although it seems to be quite directional; I have to turn it about 10 degrees to get one group of stations or another.

NOW MY PROBLEM:
The Winegard HD7000R is roof-mounted and runs through 70' of Quad-Shielded cable (Brand new from SolidSignal.com) to the Service Entry, then through another 20' to the TV. Through this cable I get "No Signal" from the HD7000R. I've tried turning the Antenna in the direction(s) that worked in the Living Room experiment but regardless of direction I still get "No Signal". I've also tried hooking up the TV directly to the end of the 70' cable and still get "No signal"

Please Advise.

-Patrick

[TomV]

if you have tested out the antenna beforehand with another coax cable (5 ft) but it does not work with the 70 ft cable, then you have a problem with the 70 ft cable.

Is it posible that antenna coupling was damaged during the roof installation?