Later this year, Shaw is launching a new satellite, called Anik G1. It will be broadcasting all HD channels.
Customers who wish to view channels from this new satellite MUST use the new Triple Satellite xKu LNB.
Customers who do not want the new channels can continue using the Dual Sat LNB.
In your particular situation, you MUST use the same LNB on both dishes, because, Shaw sends down V-codes to your receivers, telling the receivers which LNB you are using.
All receivers on the same account must use the same LNB (either a Dual or a Triple).
If you are unable to find a used dish with the Dual Sat LNB, then install a dish with the Triple xKu LNB on your Shop. Then you will have to call Shaw and have them come to your house, and replace your current Dual Sat LNB with a Triple xKu LNB on the dish on your house.
I believe thay are charging $50 for this LNB plus the cost of a service call.
The Tech then calls Shaw and tells them to update your account to the Triple LNB, and within 15 minutes, all your receivers will be working.
Whereabouts are you? I have two Shaw dishes with Dual LNB's available.