Topband: AC line bypass capacitors

[Tom W8JI]

> My 160 TX is causing RFI to one of my baseboard heater programmable 
> thermostats (switches modes, temperature, when I transmit). The thermostat 
> has a 2 wire connection to 240VAC in a metal receptacle box that has a 
> third wire common ground wire. I would like to try bypassing the AC line. 
> Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. 
> a Digi-Key or Mouser part number? Should I use one capacitor across the 
> 240VAC or two capacitors, one from each 120VAC line to the common wire? 
> Thanks for the help.
> _________________


The safest bypass method for 120V is to put one 250 VAC rated cap across the 
line, and one more cap from neutral to safety ground.

The safest method for 240V would be to use two caps, one from each 120 to 
neutral. Then use a single cap from neutral to safety ground if it exists.

This method ensures you do not screw up any GFI stuff, and if a cap faults 
it faults from a hot directly to a current carrying return and not into a 
safety system.

The caps are UL VDE CSA  rated line bypasses, available from Mouser and 
others. I would use a 0.01 uF capacitor. They are about ten ohms on 160 
meters, if I remember right.

73 Tom