Jim,
I know from something I read decades ago that turning two toroids 90deg
to each other greatly reduces any interaction.? Makes since from a E&M
standpoint.
I would think that you have to be careful with this experiment. Imagine
that the windings interlock so that they are adjacent.? Capacitance between
the windings would look like magnetic field interaction.? I'd place a very thin
sheet of plastic (say a milk carton slab) between them to prevent physical
overlap of windings.? First impression in the brain I get.? I assume that
you might do a N number of turns where N is as large as you can get.
Then try it with a smaller number of turns and the field is not self
enclosed.
The experiments I see on the web using the nanoVNA are amazing.? We
certainly couldn't do this a long time ago and maybe even a short time
ago.? I got one to play with crystals, but that is always for tomorrow.....
I'll be looking for you and anyone else on 17.? The receiver is right in front of
me all the time I'm building something and cataloging parts.
Two days ago was the first day that I couldn't get anyone and the
A-index was at 23 and K-index at 4.? I closed the band last night
with LA and a ZL.? The RBN looked like a spider web.? He must
have been running more than 5W.? :-)? And this was an hour
after the band had closed in the US.? It pays to stay up late
sometimes.? The ZL must have $50K worth of aluminum in
the air.....
Just got NY.
ciao dude,
On 4/11/25 16:09, Jim Kortge, K8IQY via groups.io wrote:
Hi Chuck,
In reading your response to my post, it dawned on me that a simple experiment might shed some light on the self shielding or magnetic field containment of toroids.? Take a pair of wound toroids, drive one with an oscillator of know amplitude with the two taped together, and measure the passive toroid with an RF voltmeter to see if there is any output.? My guess is that there will be, much lower than the driven toroid, but some coupling.? I might gin that experiment up tomorrow to see what happens.? Perfect experiment for a S/A with tracking generator, and I have one of those!
72/73 and I tried 17-meters again today for you, but no go.? 17 in really sad shape today, along with all of the other bands,
Jim, K8IQY
...snip snip...
--
chuck adams, aa7fo
QRP WAS 17m started Apr 2, 2025
WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,MN
PA,CA,CO,WI,NE,ID,IL,NC,NY
DXCC W,VE,JA,PY
