John. Fascinating stuff and all your are papers duly saved. I sort of knew PA0SE must be right and while E/H = 377 ohms between the Helmholtz coils, we have to go to the far field of an antenna befor
John. Scaling your figures to 500kHz that gives a distance of about 820 metres for 1% error, which ties in very nicely with my 955 metres, give or take. Malcolm (G3NZP) Andy, all, Last year, I did a
Hi Andy. Interesting, have a look at http://www.rsgb-spectrumforum.org.uk/radiation_theory.htm where via the 500kHz section (so presumably meant for electrically small antennas) it says "It is genera
There appear to be two meanings to the term "far field" when applied to antennas. One is usually reserved for electrically LARGE antennas and is the point where the wavefront can be considered to be
Blimey ! That is dramatic. And there is a minute wobble up to about 10 times the distance as well - which would probably give 2% - 3% error. So, in a way, one could almost say the RSGB figure "is rig
Hi. Can anyone reassure me. I am in the process of using PA0SE's most helpful article http://www.veron.nl/tech/lf/fsm/pa0se.htm to assist in calibrating my 'Eton E5' as a field strength receiver for
It's instructive to look at plots of the variation of wave impedance with distance from the source. These plots (acknowledgements to John Middleton and Marconi Insts, "Engineers EMC Workbook") http:/
Yes, it would be "certainly true" that 10 times the recognised distance is in the far field. It certainly provides a huge safety margin! Most texts use 2.pi, although I did once see 4.pi quoted. Andy
Andy, all, Last year, I did a MathCad analysis of the fields from a small vertical and a small magnetic loop at 137 kHz. The program calculated the vector E and H fields, and the magnitude of E/H for
Malcolm, Hi. Can anyone reassure me. Be reassured. Your meter is measuring the magnetic field, and the calibration setup is primarily generating a magnetic field. The cal is being done under near-fie
