X-10 Signal Strength

Below is a list of nominal baseline measurements for a variety of X-10 transmitters measured at the transmitter. Readings were made with a pre-ELK version of the ESM1 and with a 'scope through an ACT Scope-Test2. Voltages measured using the Scope-Test2 are about equal to the voltages measured using a 0.1F capacitor and 100 ohm resistor; the Scope-Test2 does not appear to have any gain.

     Transmitter   Volts   
        CM11A      5Vpp¹
        CM15A      6Vpp
        30001      5Vpp      Stanley HomeLink Transceiver
        HCPRF      6Vpp      Leviton All Housecode Transceiver
        RR501      10Vpp
        TM751-SR   10Vpp     Has FCC ID on label
        TM751-SH   5Vpp      Has "Tested To Comply With FCC Standards" on label
  PL513/PSC04  	   10Vpp
  TW523/PSC05  	   10Vpp
        CP290      10Vpp
        MT522      10Vpp
        IR543      10Vpp
    PowerLinc      10Vpp     Smarthome 1132
The ACT TI103 specifications indicate its output is 6Vpp. I have not measured it.

Based on published specifications, European interfaces (XM10E, CM11E, CM15Pro, MT10E), which must comply with Cenelec limits, all output 2.5Vpp.

Additional data can be found in a couple of usenet threads:
     Thread 1     Thread 2
Note that all of the X-10 measurement devices currently available max out at 5Vpp or less so they give an incomplete (and inaccurate) picture.

¹ The CM11A output tends to start at about 5Vpp but taper off to 3-3.5Vpp over the 1ms burst. Changing R12 as recommended by John Galvin in Thread 2 results in a steady 5Vpp output.

Although most of it dates to 2001 or earlier, there is a wealth of data on using the powerline as a communications medium at Power Line Communication Bibliography.

The effects of other transmitters on signal strength can be seen by plugging a TW523 into the same powerstrip as a TM751. The TM751 output drops from 10Vpp to 8Vpp, a 20% decrease.

NOTE: The tests were carried out circa 2003. With the exception of a TM751 and RR501 made in 2011, I have not tested newer models so do not know if there are any changes.

The following screenshots were taken using an ACT Scope-Test2 adapter. All of the 120V, 60Hz signals use a x10 probe.

X10 Module Phantom Power

We used the Kill-A-Watt meter, shown above, in cumulative kWh mode to measure the power used by various X-10 modules when idle. To increase accuracy, measurements were made over ~100 hour periods. The accuracy of the Kill-A-Watt meter was then confirmed using 1% resistors as the load and by measuring multiple X-10 modules connected to a powerstrip that was plugged into the Kill-A-Watt. Four LM465 modules plus one LM14A draw between 2 and 3 total watts with a Power Factor of 0.13-0.14.) The ProDigit datasheet (they make the Kill-A-Watt) indicates 30ppm accuracy in kWh mode.

 
     X-10 Module        OFF 
     -----------------------
     AM486              0.4W
     LM465              0.5W
     TM751              1.2W
     RR501              1.4W
     CM11A              1.3W
     CM15A              0.93W
     1132B              1.2W
     2412S              0.9W
     2414S              0.9W
We also measured the LM465 with a 100W incandescent dimmed to 0% (as opposed to OFF). The total power used was about 2.5W. While I did not use the lengthy kWh method, the readings I got using VA for an LM465 with a dimmable CFL are 15VA at full brightness and 1VA at full dim.

I also used the Kill-A-Watt to measure the power wasted (when idle) by an X-10 & Insteon friendly +5V switched-mode power supply from Circuit Specialists. It uses 0.2W when idle.

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