6-18 MHz. I’ve found huge lists of SW transmissions, all at different time slots, and it’s quite difficult to work out what’s what with the time differences. I’ll make a rotary stand for the antenna, now I know it works.
Looking at your diagram in post #25, would you simply connect a twisted...
I’ve had a chance to build the loop as per post #25 by @Baluncore using twinax cable. Even in the daytime, it was receiving some pretty strong overseas signals. Will try later on tonight. One small problem is, the stations don’t seem to announce what/where they are.
Right, some progress, but some confusion.
Standard copper pipe standoffs allow the elements to be raised into the plane of the dipole, and have a useful centre rib for alignment.
Balun cobbled together as per the design software.
I expect there will be some comments on this, and how the VNA...
Apparently, fresh water RF comms are feasible, eg:
http://eprints.gla.ac.uk/194214/7/194214.pdf
Regarding seawater, an example formula is here (page 317)...
In conductive media like seawater, EM waves experience attenuation related to their frequency. The skin depth formula calculates the depth at which ##e^{-1}## attenuation is reached. The skin depth is inversely proportional to frequency.
In practical terms, only extremely low frequencies (eg 80...
^ and there lies the rub. Domestic electrics will work if you simply hook up L/N, ignoring wire sizes, cable runs, breaker specs, and the most basic protection against fire/shock - the earth/ground wire.
At this stage I would stick to dead testing. Hopefully, the multimeter will show a low resistance reading between either L-E or N-E. You can then disconnect bits until the reading jumps back up.
Testing at 500V with a Megger, a pass is a resistance reading of ##1 M\Omega## typically. With a...
Something like this:
Any net current would be earth leakage. The AC clamp meter will miss DC leakage, which is increasingly common. There are various forms of RCD to account for modern loads:
Type AC - mains freq. AC leakage only
Type A - above + pulsed DC
Type F - above + higher frequencies...
Are you measuring all three conductors (L,N,E) inside the clamp? A more usual method would be to clamp L+N, thereby measuring all leakage, both down the earth conductor and through the physical earth.
The pass level for a standard 30mA RCD/GFCI (mandatory for all new lighting/socket circuits...
I’m also not sure of the aim, but how about something I’ve recently done, which is speccing a VFD control system for a milling machine?
Some design criteria:
FWD/STOP/REVERSE in one switch
Speed control (what range?)
RPM meter
E-stop
Power and fault indicators.
Braking, to halt the spindle...
I’ve had a reply from K&J Magnetics. They say the calculations used are proprietary and a result of thousands of man-hours of experimentation. There apparently isn’t a formula. That’s quite a surprise.
Would it be possible, as @Baluncore suggested in a previous discussion, to analyse this...
I’ve found this manufacturer who has a force calculator on their website:
https://www.kjmagnetics.com/calculator.repel.asp
I’ve asked them what formula is used.
The internet can be a confusing place. In this Fluke article, they assert that 3ph can transmit 3x the power of 1ph, implying the answer to the OP is ‘yes’:
https://www.fluke.com/en-gb/learn/blog/power-quality/single-phase-vs-three-phase-power#:~:text=three-phase power, three-,three wires...