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. Volages measured using the Scope-Test2 are about equal to the voltages measured using a 0.1µF 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      10Vpp
        TW523      10Vpp
        CP290      10Vpp
        MT522      10Vpp
        IR543      10Vpp
    PowerLinc      10Vpp

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.

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

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