If you desire a 'real' answer, many labs offer an engineering only test.
There are no reports other than engineering data. Usually the minimum
payment is 1/2-day. Some will even offer less time for engineering only
tests. Once you have the engineering data, you know the bad frequencies.
Take the product 'home' and set it up on the bench in an environment with
minimum conducting surfaces, set up an antenna, a clip lead will do in many
cases but you may prefer a 1/4-wavelength radiator trimmed for specific
frequencies, and connect that to a spectrum analyzer. Be sure you choose
an area for setup that is physically stable (not a lot of movement of
anything over time). As far as the spec an goes, the AirSpy R1 or R2 has a
spiff application that comes with the free download of SDR#. It covers
roughly 20 MHz through 1.8 GHz. FCC and the EU do not measure radiated
emissions below 30 MHz and I doubt your product has any energy above 1 GHz,
so that is a good "quick and dirty" solution that will cost you around $200
and the use of a laptop or PC with USB2 or greater. The application is
called SpectrumSpy and can scan a little as 10 MHz at a time or as much as
the whole range the receiver covers. FCC and the EU also require
measurement of conducted emissions - the line cord. You can do this with a
normal o'scope, with limitations.
There are also a number of small private companies (mine, included) that
offer a pre-compliance evaluation. They will not be able to accomplish
what a calibrated range will give you, but are far less expensive and will
identify problem frequencies and areas that likely need work before you
spend the big bucks at a fully accredited lab. Most of these smaller labs
will also work with you to reduce any 'low-hanging-fruit'. Most are
'maned' by retired EMC engineers with decades of experience in the real
world.
Dave - WØLEV
On Fri, Feb 21, 2020 at 1:33 PM Charles Gallo <charlie@thegallos.com> wrote:
> Hey Gang,
>
> It is starting to look like the company I'm working for MAY (note the
> MAY) start selling complete devices, vs components, which of course
> means Part 15 etc.
> Now, as far as we know, simply because of what we measure, out existing
> stuff is low noise (I2C bus on one side, all uV and mV level near DC
> (basically DC, but the levels tend to fluctuate over many minutes -
> think temperature in a fish tank, or pH - makes for the worlds most
> boring graph why you look at a number that is either 7.1 or 7.2 all day,
> every day, and the value is a DC mV signal. We had to do a LOT of work
> to make the circuits EMI clean on the INBOUND signal, which tends to
> clean up the outbound
>
> Anyway, I'm thinking "How do we informally test our stuff BEFORE we go
> out to the Part 15 lab?"
>
> My actual biggest worries are the USB power supply (I posted one here,
> someone asked RE RFI - quick answer - the Made in the USA version SEEMS
> ok, the one that looks the same, weights 1/2 as much and costs 1/2 as
> much from China is a POS, and we're never ordering them again), and
> believe it or not, the Raspberry Pi we plug our probes into.
>
> Anyone know of a good informal way? I assume a spectrum analyzer, with
> some probes...
>
> Also anyone know if the RPi is clean, assuming clean power in?
>
> --
> 73 de KG2V
> Charles Gallo
> http://www.thegallos.com
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
--
*Dave - WØLEV*
*Just Let Darwin Work*
*Just Think*
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