[RFI] Nighthawk CO2 Detector

Mon, 19 Aug 2002 11:00:53 -0500

A 500pF cap (around 40 ohms @7.5MHz) rated for 230Vac would also work in an
X configuration for differential noise. The cap will be usefull also in a Y
configuration if common mode noise is the problem, or a free sample power
filter from Cor.com or SAE or Shurter.
X-configuration means from phase to nuetral. 1-cap
Y-configuration means from Phase to earth ground and Nuetral to earth
ground. 2- caps
Michael Findley, NCT
Compliance Engineering
512-683-8797 office
512-683-8880 FAX

                      ke2n@cs.com                                                                                                      
                      Sent by:                 To:      RFI@contesting.com                                                             
                      rfi-admin@contes         cc:                                                                                     
                      ting.com                 Subject: RE: [RFI] Nighthawk CO2 Detector                                               

                      08/19/2002 10:32                                                                                                 
                      AM                                                                                                               

They have a web site where you can ask a question, although its unlikely to
be fielded by an engineer ...

http://www.kiddesafety.com/kiddesafetycorp/contact.html

The company would probably be happy to sell you a battery powered version
of the same thing - that should be inherently more immune

Ken

PS - we suppose you mean CO detector, not CO2 detector....

>
>> -----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
>
>_______________________________________________
>RFI mailing list
>RFI@contesting.com
>http://lists.contesting.com/mailman/listinfo/rfi
>
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi