One thing you should realize about line filters is they are optimized for
conducted line emissions coming from the product where they are built in. This
means the line / load labeling will determine your best orientation for
connection. If you are attempting to protect your own gear, you can reverse a
filter if you wish and there will be no harm to the filter itself. Also, the
case of the filter needs to be well bonded to the chassis of your equipment.
As for the effectiveness of a line filter, much of a filter's design is not
just the components but the internal layout of the components and the internal
wire routing. I have worked professionally with line filters for many years and
if there's anything I have learned it is that manufacturer's data sheets have
little to do with your specific application. For one thing, all the
measurements they report use 50 Ohm matched signal generators and analyzers.
The real world of power lines are a far cry different than 50 Ohms.
Possibly, the best thing you can do is to perform your own sweep using a LISN
or a Tastkoph probe which will protect the analyzer from the line voltage.
Identify what is the RF noise profile you currently have, then locate a filter
that has good attenuation numbers at the points of concern. Most of the time
line filters are effective in the 100 kHz to 100 MHz range.
All the best, Doug
Douglas E Powell
dougp01@gmail.com
https://www.linkedin.com/in/dougp01
Original Message
From: Dave Cole
Sent: Monday, August 15, 2016 5:41 AM
To: rfi@contesting.com
Reply To: dave@nk7z.net
Subject: Re: [RFI] ebay line filters
On Mon, 2016-08-15 at 10:02 +0100, PY1NB - Felipe Ceglia wrote:
> Hello,
>
> I need to buy some EMI line filters in te range of 3 to 10 amps. I
> found a plethora of them at Ebay, but none of those I found had tables
> or curves for how much they attenuate on the spectrum.
How odd it is that you ask that, just yesterday I was looking at eBay
for a line filter, and decided I needed more information. I located
this:
http://www.te.com/usa-en/products/emi-filters/power-line-filters/interse
ction/high-performance-power-line-filters.html
Which will give you a secret decoder chart for the Corcom filters...
--
73's, and thanks,
Dave (NK7Z)
For software/hardware reviews see:
http://www.nk7z.net
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