I had a BC 20 on my previous truck, which is very similar and may actually use the same transmitter. To help you visualize, if you were to lay the transmitter flat on its back on a table, the best transmission direction would be straight up. Hope that helps.
I'm done. This isn't a place to be helpful. It's a place where curmudgeons with a superiority complex will nit pick everything. If you want help, go elsewhere. Admin, delete my account please.