There's a number of possibilities;
Try checking signal strength using Ch. 252 and Channel 700.
Ch.252 is used for the new TRIPLE XKu LNB.
At the house, did the Installer use new cable or existing cable from an old satellite installation? If they used existing cable, make sure there are no splitters or switches installed inside.
There should be a single cable straight thru to the receiver.
Was it a Shaw Installer or a private installer? If it was Shaw, he/she should've confirmed good signal before he left.
If it was a private installer, they may have misaligned your dish.
Are you sharing an account with someone? If you are, the Primary Account holder may still have the older DUAL SAT LNB's on their dish. That means that ALL the receivers on the account, including yours, will be programmed for the older LNB.
Did you try the receiver in the RV? Same result or does it work?
Is your receiver a Dual-Tuner (two input) receiver? If yes, are there TWO input cables? If not, make sure a splitter is not being used.
Dual-Tuners MUST HAVE two input cables.