I have 3 buildings on my property, with X10 modules, light switches, etc. in all of them.
An XTB-IIR+ at the main panel serving all 3 buildings worked great. Until I had to install and industrial-strength surge protective device.* That puppy includes a great noise filter, and it killed the X10 between buildings. X10 works fine within each building.
I tried a pair of PAC03 RF transceivers as an experiment to link 2 buildings, but both were DOA. They responded to PLC signals to turn the relay on/off, but no response to any signals from a known good KR22A. Two of the buildings are physically close enough that the PAC03s should receive each other. If that works, I'm willing to build a better antenna or add a preamp to the PAC03 or CM15a in the third building, which is ~200 feet away.
All buildings share a common computer network, with wifi available in each building. The WM-100 transceiver looked interesting but I want to continue using AHP, and I won't use anything that requires interface to the cloud. I haven't found a transparent wifi-PLC transceiver.
Any suggestions? I still have the XTB-IIR+, although it doesn't see any signals when mounted in the main panel. No fancy 32-bit X10 kit, just CM15a, dimmers, appliance modules, wall switches, smart outlets, etc.
*The house in on a hilltop in a part of the country that gets a lot of lighting. I've installed lightning protection system (aka lightning rods) on each building, and have 2-layer surge protection, a big one on the main panel, and smaller 27 kA units in each building's sub-panel. The big one was rated 65kA. "Was" because a direct hit to the power line about a mile from here fried it, killed 2 computers, a router, and sundry other devices. A power line disturbance monitor saw peak voltages above 1000 V; normally the 2-layer SPDs limit surges to less than 600 volts.
Now the main surge protector is rated 300kA. Industrial units include very good noise filters.