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ANTENTOP- 03- 2003, # 004

Current Distribution in the A.L.C.


Below   --100ma & Above  --79ma


When I moved the coil to the top of the mast and made a horizontal "X" top hat to resonate it back on the same freq, I got

Below  --100ma & Above  --47ma

So, It happens even in a totally shielded loading coil with miniscule power going thru it!  Kirchoff has no laws about current being the same on both ends of inductors. His current law is about one POINT in a circuit and his voltage law is about a closed loop."

... and some significant difference W9UCW in field strength measured between the base and center loading coil:

"The actual difference in signal strength between top and base loading of a 9' antenna is about 16 db (measured) on 75m, but Tom calculates 8db on 160. That's because he assumes the same current in the coil. Actually it's worse on 160 than 75."

Barry's  pictures are worth a thousand words:


W9UCW's setup with radial field (60), base loaded vertical with RF thermocouple ammeters inserted at the top and bottom of the coil.



Here is the coil in center loaded radiator, 100 mA meters at both ends of the coil. The bottom one is showing full deflection (with power adjusted to) - 100 mA while at the same time the top ammeter is showing 45 mA as described above. The meters were mounted that way so that they could do a test and then just turn the coil assembly upside down and do another test to make sure results were the same and that no anomalies crept in. Results were always identical.


The reality.

So how does the real distribution of current in loaded antennas look? The answer can be found in the John Devoldere's "Bible" - "ON4UN's Low Band DXing", 3rd Edition, on page 9-34: (see page 57)

When I pointed out this reference to W8JI, his response was:

"I just looked at that, and you are right. John is incorrect, and I'll bring it to his attention. Thanks for pointing that out."

This is not the first time that W8JI is wrong. His typical modus operandi is first to attack and ridicule the opponent, then the exchange of arguments ensues. When he realizes he is wrong, rather than admitting, he clouds the issue with his "arguments". After staying quiet for a while, he then emerges, pretending to be the expert on the subject with corresponding postings on his web page, without giving credit to the originator. Normally this is called plagiarism. 

The Internet is a great place to publish ideas, good and wrong. In the spirit of Tom's posting on the's purpose, I had to react to his disinformation by presenting the facts, especially when it happened more than once. 

Why is this important? Technical subjects have their laws and rules. Perpetuating wrong information doesn't serve anybody. As we can see in this example, something that was "established" 50 years ago, perpetuated through "peer reviewed" books to this day, can cause problems and wrong conclusions.

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