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Re: Topband: AC line bypass capacitors

To: Charlie Cunningham <charlie-cunningham@nc.rr.com>, 'Paul Christensen' <w9ac@arrl.net>, "topband@contesting.com" <topband@contesting.com>
Subject: Re: Topband: AC line bypass capacitors
From: HAROLD SMITH JR <w0rihps@sbcglobal.net>
Reply-to: HAROLD SMITH JR <w0rihps@sbcglobal.net>
Date: Wed, 4 Feb 2015 18:16:29 -0800
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Hi Charlie,

I can remember when the Collins S-Line used .01 600volt disk ceramic capacitors 
on the power supply connector. They were from the AC switch to ground. They 
were almost always burnt and many times only the leads left. 

73 Price W0RI


On Wednesday, February 4, 2015 6:31 PM, Charlie Cunningham 
<charlie-cunningham@nc.rr.com> wrote:
 


Hi, Paul

For AC line bypass capacitors look for UL-rated Ceramic Disc capacitors that
typically have AC working voltages like 250 VAC or higher. These are
designed and rated for AC line service and can take the surges that occur on
AC lines.

Check Digi-Key, Newark and others - you'll find plenty!

73,
Charlie, K4OTV



-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Paul
Christensen
Sent: Wednesday, February 04, 2015 3:55 PM
To: topband@contesting.com
Subject: Re: Topband: AC line bypass capacitors

>
>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.
> _________________

As a substitute for X1 Y2 line caps,  an in-line RFI/EMI filter can be
used that already contains the X/Y-rated caps.   See the bottom of p. 21:

http://audiosystemsgroup.com/RFI-Ham.pdf

These filters can often be cannibalized from old PC power supplies and
discarded industrial equipment.

Paul, W9AC


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