The whole-house X-10 blocker/passive coupler that I have used for years works well, but there are one or two outlets in the house where communication could be improved.  I decided to install an active repeater to address this problem and purchased one from Worthington for $85.00.  I installed the unit into the wall of my utility room from where all the wiring in the home originates, and where the breaker panel is located.

Each X-10 transmission consists of two identical halves.  The CR230 repeater works by decoding the first half, and then sending out a copy of it which occurs concurrently with the second half of the transmission.  As a result, the signal strength of the second half is much higher than the first.  This can clearly be seen by my ESM1 X-10 Signal Strength Meter.  I see a short bar blip on the display (from the original sender) followed by a long bar (amplified by the CR230).  This is a very distinct signature as all previously seen signals produce two bars of the same length.  It is not known if the CR230 phase locks onto the 120 KHz signal by the original sender, but if I were to design this box, I would certainly have done that.  This would ensure that the signals of the CR230 and the original transmitter are in phase, and would not interfere destructively.

In my research of the device, I tried to find out if all X-10 receivers would work with just one copy (half) of the full X-10 message.  This is because regions in the home that have weak signal would only 'see' one half of the command (the half that was amplified by the CR230).  The general consensus on the newsgroups is that reception would work with all devices.  Also, Phil Kingery from ACT advised not using both the CR230 and the CP303 in the same installation.  I have not found this to be a problem.

In actual testing I have found seamless behavior, and communication over the whole house has improved.  There are two particular breakers/zones that are problematic, and initial testing shows this has improved considerably.  Further use will show if this is a good permanent solution (see Project log below).

Links

Project log

• July 2003 - Purchased and installed unit into utility room.
  
• December 2003 - One particular outlet that is mainly used for Christmas decorations has always been difficult to control by X-10.  This year communication has improved, but is still not completely good.  This outlet can now be controlled from the main control system, but not by all controllers in the house.  All other communication problems appear to have been resolved.