[RFI] Wireless intercoms

[Pete Smith]

My wife got me a pair of wireless intercoms for Christmas so that we could 
communicate back and forth between her office and my shack, on different 
floors.  They are Westinghouse WHI-2C, which operate FM at a frequency of 
about 240KHz on the power line.

My problem is that these intercoms seem to have a very high noise level 
whenever one or the other unit is transmitting.  The noise sounds like 60 
Hz, though given that it's FM it lacks the characteristic AM sound of power 
hum.  When they're not transmitting voice, both ends are 
quiet.  Westinghouse tech support speaks vaguely of fluorescent lights 
(none in the house), dimmers (ditto) and of not running the intercoms 
through a power strip with EMI filtering (I'm not).  I've tried them 
plugged in to various pairs of outlets, with essentially no change.

Is this pretty much standard with this technology?  Are there other units 
that people have found better than others?  What about VHF wireless 
technology (like 900 MHz?)

73, Pete N4ZR
Check out the World HF Contest Station Database at
  www.pvrc.org/wcsd/wcsdsearch.htm