There are two types of phase couplers - inverting and non-inverting. SAI makes the inverting style and PCS / HAI offer the non-inverting style. SAI says that inverting phase couplers work better when the utility transformer is less than 200 feet from the home and they also say that you can put in multiple inverting phase couplers in homes with multiple breaker boxes. There is some evidence that installing multiple non-inverting phase couplers in the same home can be detrimental. If the transformer is more than 200 feet away, then a non-inverting phase coupler might work better. We've had very mixed results using phase couplers. In most cases, either style phase coupler will improve signals, but depending upon the installation, one might improve them more than the other. On occasions, we have had users try both styles and keep the one that works best for them. Sometimes, we have used phase couplers on hand that we'll use for this testing, so contact me if you want to consider this. I can't promise anything, but we can try. There was another comment on the thread about an inverting phase coupler actually lowering signal levels. We have seen a few instances of this also, but it seems that it impacted stronger signals and didn't affect lower signals much, if any. If it lowers strong signals some, but helps lower signals, then we'll accept that compromise.
