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ANTENTOP- 01- 2005, # 007  

Nonlinear Propagation of Radio- Wave


 About 21-00 UTC I worked with Uruguay, CV5D, operator Lu. The same story, at 5 watts no QSO, at 10 watts 579.


After 21-00 UTC the 20 meters band was closed.


Regards, Vladislav, RX3ALL 72!--

Vladislav met with a very interesting phenomenon, which is named (by me) nonlinear propagation of radio- wave in ionosphere. The phenomenon is, that at some small power (say 5 watts, as Vladislav had) it is impossible to do a QSO, nobody answers,  however, if the power is a little increased (say to 10 watts, as Vladislav did), the QSO is going on 59.   As a rule, this phenomenon is observed at DX QSO, if the distant is more than 2000 kms.


I have noticed this phenomenon in 1980s. At the times I had ham call UA3ZNW and I often sent CQ at 10 meters using a home brew transistor AM transmitter. 12 Volts from a PSU with manually variable voltage was going to the PA of the transmitter, and I had 3- watts RF power. 


So, at the times I have met the same phenomenon as Vladislav met at 2005. When 12 Volts feed the PA, nobody answers, BUT, when 16 Volts feed the PA, I have received 59 from far stations. My transmitter runs 5 watts when 16 volts were across PA. So, it impossible explain, why at 3 watts GUHOR, but at 5 watts – ’59.’ Usual theory of radio- propagation has no answer on the question.


I have noticed one more interesting effect of nonlinear propagation of radio- wave in ionosphere. It is possible to name this phenomenon as a trigger effect. The phenomenon is that at some small power (say 1 watt) nobody answers. However if the power is a little increased (say to 2 watts) you have received 59. Then power decreased (say, again to 1 watt) but anyway you have received 59 from your correspondent.


At first I noticed trigger effect at 10 meters band. Since an RF transistor of my PA was overheated at 16 volts, I worried, that it would go out of operation during QSO. In 1980s the RF power transistor costs pretty penny. So, I called my correspondent when my PA was fed by 16 volts, after that reduced voltage to 12 volts, and made QSO. As a rule, the QSO was completely done. The truth, sometimes during QSO my signs were ceased, then I again increased the voltage to 16 volts for a while.


A power radio station located in my city also could be the cause of the trigger effect. For example, I for a long time call DX station, no answer, then power station from my city have made QSO  with the DX, after that the DX gives me 59. Such phenomenon often is observed by me in contents, when I try QRP. I call for a long time a far station, no answer, then a powerful station has made QSO with the DX. That is all, the DX gives me 599. 


At first I thought that these strange things are only on 10 meters. But then I observed the phenomena on others amateur HF bands, from 160 up to 10 meters. The truth, on the 10 meters these phenomena are more sharply than on low-frequency HF ranges. Lots of hams and professionals also are familiar with the strange phenomena. My attempts to find a science explanation to these interesting phenomena are failed.


Professionals and scientists in personal talking about the phenomena sad me, that it is a whim of propagation or lack of my antenna or lack of the receiver of my correspondent. May be… But by me this effect was marked at various receivers, both self-made and professional, at different antennas, on diverse bands, and at stable (for the time) propagation…




... It seems to me this riddle is still unsolved …


73/72!  I.G.





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