Stefan,
You mentioned “different coil concept” for more power. I’m doubting that any of the following are desirable but I thought I’d mention them in case one them prompts an actually-good idea:
a) A hermetic shell made by filling a 1/4" space between cylinders with temperature-cured hard-epoxy; pressurized. Very dry, and better position on the Paschen pressure/voltage breakdown curve.
b) Using higher permeability lower-loss Metglas cores* to allow spaced turns, which would reduce proximity loss (and associated voltage); and to allow thicker wire (lower loss-voltage).
* (I bought some Metglas AMCC4 and AMCC-1SX cores at low cost from a surplus supplier; haven’t tested them yet)
c) Using one or more series capacitors in the coil (-5j,+5j,-5j,+5j,-5j,+5j… fun to think about, perhaps a practical nightmare even with CW, but HV balanced stacking is much better than it used to be. Seems good for a high-current resonant small-loop antenna but even in that case unwieldy for QSY)
73,
Jim AA5BW
Hi VLF,
The repetition of yesterdays message failed. At 15:38 UTC the safety function tripped. I've just been on the roof, when re-starting the transmission i can see a spark in the center of one of the stacks. So now there is another one which has a flash over! :-(
It must be replaced, which is a lot of work. So the tranmissions on 3675 Hz will stopp for some time. At least we have some carrier detections and even EbNaut decodes.
I need to think about a different coil concept.... More current, more voltage, more power, more more more!
Am 13.08.2017 16:57, schrieb [email protected]:
Stephan wrote:
“The phase of that best decode is quite varying”
Is that observation based on the attached EbNaut Decoder window image from Markus?
It is just based on that decoder data. It is not really proof, just an idea.
Would it help to have an FDTD diurnal phase plot for this path at 3575Hz?
For sure it would be interesting! If you like, do it. I would be curious to see it.
73, Stefan
