I changed a little bit the design and I found that with a “short circuit” of the upper coil the signals are much stronger... below my scheme and the wspr spots (up to 2600 km).
I attempted some FT8 QSOs with no results but I have been received looking on pskreport website, so even with FT8 some qso should be possible.
My tests were done both indoor and on my balcony so no strange coupling is noticeable, the antenna was placed vertically, I think that it works like a loop antenna oriented horizontally (not a vertical loaded one since my upper end is grounded).
The “strange” good results around midday and early evening when the critical frequency was around 7 MHz seem confirming a sort of NVIS transmission (quite strong signals and local receivers).
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| Riccardo's 40m spots on WSPR |
Often it is best to ignore experts and just experiment to see what works. Often the so called experts do not know and are just spouting myths they were (wrongly) told years before.
2 comments:
That would be a nice experiment....not really complicated. Of course the challenge with such a antenna is to be heard at other stations. 73, Bas
There is a myth that ferrite rods will not work on TX. As long as the ferrite does not saturate this is just not so!!! This of course means QRP powers, but for modes like WSPR and FT8 this may be fine in many situations.
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