[RFI] Solar panel RFI

[Dave (NK7Z)]

Thanks Dave!!

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 2/20/22 15:48, David Eckhardt wrote:
> Nothing fancy.  I'll attach an image of the test fixture I use.  It is 
> not appropriate for frequencies much above 54 MHz, but works fine for HF 
> on downward.  In determining ferrite material, one does not need 
> coverage above even 10 MHz.
> 
> Dave - WØ LEV
> 
> On Sun, Feb 20, 2022 at 10:48 PM Dave (NK7Z) <dave at nk7z.net 
> <mailto:dave at nk7z.net>> wrote:
> 
>     Jim,
> 
>     That is most interesting material, thank you!  Will you all be
>     including
>     a test fixture description as well?  I am in the process of gathering
>     the materials to build a test fixture, and would like to see your
>     designs...
> 
>     73, and thanks,
>     Dave (NK7Z)
>     https://www.nk7z.net <https://www.nk7z.net>
>     ARRL Volunteer Examiner
>     ARRL Technical Specialist, RFI
>     ARRL Asst. Director, NW Division, Technical Resources
> 
>     On 2/20/22 12:28, Jim Brown wrote:
>      > On 2/20/2022 4:13 AM, Hare, Ed, W1RFI wrote:
>      >> The toroids are not marked, so it will not be certain what material
>      >> they are."
>      >
>      > Thanks. For the next Handbook, I've given Ward details of a
>     method to
>      > identify a few MnZn ferrite materials with an ohmmeter. It was first
>      > suggested by W1HIS, and I fleshed it out a bit further. It's pretty
>      > simple. It worked with the three VOMs in my lab -- a Simpson 260, a
>      > Fluke 8060A, and a nice little no-name digital VOM that I bought for
>      > about $15 at a northwest Indiana hamfest at least 20 years ago.
>      >
>      > With the meter on a high range scale, aggressively scratch the
>     surface
>      > of the ferrite with the probes so that they get through the
>     coating, and
>      > note the reading, if there is one. #31, #75, #77, and #78 are MnZn
>      > mixes, and will show a reading in the range of 100K - 700K; #75,
>     #77,
>      > and #78 will be in the range of 1K - 10K. #43, #52, and #61 --
>     are NiZn
>      > materials, which have MUCH higher bulk resistivities, and will
>     show no
>      > conductivity at all. These resistivity values, as well as initial
>      > permeabilty (mu at low frequency) are tabulated in early pages of
>     the
>      > Fair-Rite catalog.
>      >
>      > We're also including methods to zero in on the specific material
>      > measuring inductance using traditional methods or studying the
>     shape of
>      > an impedance sweep with a well calibrated Vector Analyzer.
>      >
>      > These methods, of course, depend on knowing AL or ui values for the
>      > various materials. Fair-Rite's published data is FAR more
>     extensive than
>      > any other manufacturers; others publish little more than
>     marketing or
>      > limited applications data. For example, Laird (used to be Steward)
>      > publishes ui values for only two of about eight materials.
>      >
>      > 73, Jim K9YC
>      >
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> 
> 
> -- 
> *Dave - WØLEV*
> /*Just Let Darwin Work*/
>