[RFI] Solar panel RFI

[Jim Brown]

On 2/20/2022 2:48 PM, Dave (NK7Z) wrote:
> That is most interesting material, thank you!  Will you all be including 
> a test fixture description as well?

Yes. One of several jigs I use is a BNC to Pomona male adapter with 
alligator clips fitting over over the male pins. I use it at the end of 
a suitable piece of RG400, and dangle it off the arm of a chair. For 
calibration, I use a piece of #10 copper, folded over and covered with 
solder as a short, a 1% large format 49.9 ohm chip resistor. To verify 
calibration at high frequency, I use a similar chip resistor, 5K or more.

I don't trust this jig for precision much above 10-15 MHz, but it's 
plenty good for this purpose.

I can get repeatable results measuring a single turn (one pass through 
the core) for everything I've tested with the exception of #61, which 
comes nowhere near data sheet values for ui for a half dozen cores I've 
measured. This one must be identified by its extremely narrow resonance 
at HF.

As of a few days ago, Ward had sent it to layout, along with printouts 
of VNWA log impedance sweeps of the 12 and 16 turns through the six 
mixes of Fair-Rite 2.4-in o.d. toroids in my stash -- #31, 43, 52, 61, 
75, and 78.

73, Jim K9YC