LAMP-MODULE >>> 10-FEET >>> CINDER-BLOCK-WALL >>> 10-FEET >>> TRANSCEIVER(OUTDOOR) >>> 20-FEET-LINE-OF-SITE >>> TRANSMITTER
So the transceiver is outdoors, your key fob is only used outdoors also. You use the fob to turn on inside lights as you approach house(?).
I think you said the transceiver is under the porch, so must be near to ground. Can you elevate the transceiver? Can you test by putting transceiver on an extension cord and get it out from under porch and a few feet off the ground? I realize this isn't the way it can stay, but is a test.
Also is there an outlet on the inside wall of the porch? If so, can the TM751 go there?
If someone else already went down this road, my apologies, I just woke up.