^^^^THIS !^^^^ I haven't looked at the syllabus for the VK Foundation license, but the UK exam is very similar to our Technician, with perhaps less math. The beauty of ham radio is that we have all kinds here. I would prefer to see the license exams oriented toward practical and timely understanding of the principles: i.e. "explain how resonance works" rather than "calculate the resonant frequency given the capacitance, resistance, and inductance of the circuit". When the principles are understood, the formula can be found rather quickly. Understanding is better than memorizing.
I agree with both of you for the most part. That's why I tried to make my comments above in the nature of an explanation about two important concepts involved. It's also why I allowed for two possibilities motivating the podcast: either a lack of understanding requiring more knowledge, or an attempt to exploit lack of understanding to generate clicks with a podcast. Unfortunately these days, there is much of the latter on the web, often cynically done for ego or income, and one must constantly be on guard. I certainly hope the OP is not in this category. In my opinion, the OP places himself in a public position of influence on ham radio with some appearance of authority by making podcasts and promoting them prominently on QRZ and perhaps elsewhere. By doing so he will unavoidably invite comments on his endeavors regarding his level of expertise and experience on the topic.
re: "Empirical evidence and the scientific method" Is this a thread where I can post where Kraus* is wrong? . * Kraus, like in John D.
Since Onno's stuff is podcasts, shouldn't ALL of these be labelled as 'podcasts', not 'News'? Some are, some aren't. As far as I am concerned, anybody can say anything as a 'podcast'. People will respond in-kind. But as 'news' we should be cognizant of the 'fake news' age we live in....
Why is this relevant? Because practically every loop calculator on the planet uses the same formula to calculate an incorrect feed point Z.
Here's the part where Kraus is wrong, and, apparently every loop calculator follows this formula (notice, Kraus himself is choosing a Lambda/3 circumference loop for a numerical example below): The real, measured loop impedance comes out to be around (for a Lambda/4 circumference loop) about 22.5 Ohms. I'm thinking that KK5JY found his loop to be more like 50 Ohms (thereabouts) on a Lambda/3 circumference loop. Another ham here on the board I exchanged info with also came up closer to my values for a 6 meter (I think it was) Lambda/4 circumference loop. Added: Ben Edginton also found the 22 point some-Ohm value. Here is his story on this subject: http://www.g0cwt.co.uk/magloops/new_page_2.htm
Revised - Even Ben was taken-in by the errors propagated throughout the years on this. Here's an entry from his website on this subject: My first attempts did not work I had taken information from the ARRL Antenna book which told me that the radiation resistance of the loop would be less than 0.1ohm on 80 metres and I took this to be the feed point resistance as it appears does every one else I have spoken to . At 50 ohms to 0.1 the impedance ratio is 500 to 1 this means the square root of 500 = 22.36 so the transformer would have to be 22 to 1 . turns ratio. I first located two ferrite tubes that I thought would be suitable and put them side by side and used two copper tubes to make the secondary 1 turn winding ,using two end plates made of copper clad board I then wound 22 turns of wire through the center to make the primary winding . I now had my 500 to 1 impedance ratio transformer I connected it in series with the remotely controlled tuning capacitor and the 64 foot of wire loop that I had pulled up the 25 foot mast. I went down to the transceiver and tried to tune up on 80 metres , no chance not even a hope checked everything and tried again no possible SWR reading . I decided that the problem was the matching transformer but how to find out ,well I began to reduce the number of turns on the primary winding and found that when the turns where reduced the SWR began to show results but it was not until the primary was down to 2 turns that I could get anywhere near to a 1 to 1 swr. From: http://www.g0cwt.co.uk/magloops/new_page_6.htm
You haven't spoken to the right people yet Radiation Resistance is not the same thing as Impedance at Resonance (especially not for small in terms of wavelength antennas). If you would like to expand your knowledge about it, Wikipedia has a fairly good treatment on it, at least on today's version of the page: https://en.wikipedia.org/wiki/Radiation_resistance
Here is an example of a popular loop calculator on the interwebs that yields an incorrect result too: Note the Radiation resistance value. Add that value to the AC resistance (Loss Resistance) value of 10 ga. copper used above and one *still* comes off a calculated factor of 10 lower than the measured Loop feedpoint Z values. This calculator (http://www.66pacific.com/calculators/small_tx_loop_calc.aspx) is presumed to use an equation near to being the same as the John D. Kraus equation as detailed further above.
And I quote, again, from Kraus: This is the radiation resistance of a small single-turn loop antenna, circular or square, with uniform in-phase current. Those words are plainly visible on my monitor, how about yours? Can you yet explain why Kraus is in error, why his equations don't match reality? Time and time again, as measured by different 'operators'? Not just a 'case sample of one'. Maybe you missed those points. Four different individuals by my account, now. Maybe you didn't glean that from all the foregoing? These 'things' are simple enough to measure today with something commonly known in the amateur community as ... antenna analyzers. They even show up all the time on the swap-meet forum on this website! .
