look at this info,
the listeing is for many types and applications for the filters, but be
sure you filter
the green wire ground as well.
http://www.corcom.com/Series/RFI.asp
On Tue, Sep 24, 2013 at 3:16 AM, Christopher Brown <cbrown@woods.net> wrote:
>
> There was a fairly simple filter in the older handbooks, but it was not
> really targeted at switched mode noise.
>
> There is also the issue of building something that is functionally
> included in your house AC system.
>
>
> As far as snap-ons, unless it is big enough to take multiple turns of
> the power cord it is not going to do anything useful on HF.
>
>
> You might try visiting Corcoms site (cor.com).
>
>
> First off, they have 100+ filters designed for various things, and are
> generally considered to be good quality.
>
>
> Second, datasheets w/ schematics and performance charts against a STD
> LISN network test setup.
>
>
> They can be had from mouser, or often surplus and are sealed metal case
> smaller and better built they most can do themselves.
>
> I used to build my own, but these days I use the filters I have colleced
> over the years as building blocks (generally combined with a nice
> enclosure and addition ferrite toroids).
>
> If you really want to build...
>
>
> Review the Corcom datasheets, look at the schematic and pay attention to
> the atten curves for the filter design at each power rating.
>
> The schematic will not generally have component values as they are diff
> for each power rating.
>
> Find the filter model that best matches you need.
>
>
> Now, google the P/N or search fleabay... Fun fact, while the data
> sheets do not have component values, the schematic usually printed on
> the case generally does.
>
> You can often get the inductor and cap values just by finding a picture.
>
>
> Of course you then need to determine the correct core materials and
> figure out the winding style, Z wound combined common/diff mode cores
> are common in the higher amperage filters.
>
>
> I run a 3kva rackmount UPS here, not a full time just a heavy duty true
> sine w/ external battery capability for long run times.
>
> The charger is a bit noisy, the ethernet card is noise and when
> producing power, goodby HF.
>
> I ended up removing the outlet bank and placing a pair of Corcom 30EMC6
> filters inside. One on the UPS input and one in the out...With a single
> large cable for the feed out to a L5-30 socket.
>
> At 30amps, the EMC and S series looked best...with a smaller load
> available attenuation is much higher, just remember to account for full
> UPS load and full charge current.
>
>
> On 9/23/13 6:39 AM, Ray, W4BYG wrote:
> > Did a search online for info on how to build some AC line filters with
> > little luck. They are fairly simple to construct, but I need the correct
> > values for the spectrum of interest.
> >
> > Also not sure what input/output impedance to use for the filter calcs.
> >
> > Does anyone have any guidance on where to go for good info on building
> some
> > dual section AC line filters for 1.8 to 30 MHz?
> >
> > Looking to minimize conducted and radiated noise from switching supply
> power
> > cords and my double conversion (full time) UPS in the shack. Snap on
> > ferrites aren't helping enough.
> >
> > Your assistance would be appreciated.
> >
> > Ray, W4BYG
> >
> > _______________________________________________
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> > RFI@contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
> >
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