[RFI] Nighthawk CO2 Detector

[EDWARDS, EDDIE J]

> -----Original Message-----
> From:	Chuck Gooden - N9QBT 
> I am having RFI problems with a Nighthawk CO2 detector when I operate on 40 
> Meters.  Does anyone have any Ideas on how to get rid of this problem.
> 
> I am planning to try a Ferrite core on the AC Line (hot lead only) inside the 
> electical box as soon as I can get some but any other ideas would be welcomed.
> 
	If the signal is coupled to the line in differential mode, then this might work although in in-line coil would work better; but usually it's induced common mode onto the line.  If it's common mode, then you need to wrap the whole power cable (hot, cold & grd) onto a ferrite.  Here's a diagram (hope it comes through OK):

	Differential Mode:
	              induced signal path ----->
	                          ______________________
	AC POWERLINE ______________________
	                                           <-----

	Common Mode:
	           <----------
	     ____________________
	AC ____________________
	            <----------

> The CO2 Dector is Model KN-COPP-3, Assembly #900-0076, Manufactured 17 April 
> 2000.
> 
	Be sure to contact the mfr to let them know about the RFI problem.  Usually, telling customer service is a waste of time.  Find the people who care about such problems (if they even exist!).

	73,
	de ed -K0iL