I suspect new equipment is available since the most recent thread I found on this subject so ...

I need to couple and amplify X-10 signals in my home which has the following characteristics.
- 4500 Sq ft.
- 400 amp service (Two 200 AMP panels)
- Whole house surge suppressor in each panel

What coupler/amplifier is the best for my situation? Do I need one in each panel? (The panels are both fed from the same meter base as is typical.)

Thanks for any help.

The ACT CR 230 coupler/repeater is generally well regarded and I have had one installed for about ten years.

I would think you would need one in each panel, but for better information you might try the forums at:

[Link: cocoontech.com]

They are to Home Automation what this site is for Remotes.

JV Digital Engineering makes a unit that if the most powerful amplifier/repeater I've seen. It's called the XTB-IIR. Not only is it an amplifier and a repeater but it also has a jack so it can directly replace your PSC05 or whatever other input interface you use. You can buy it either as a kit or fully assembled. 

Here's a link to their website: jvde.us/