You wrote on May 31, 2019:
I don't know where you got the idea that altering the antenna's dimensions wil cause it to stop working. It will 'work' with a vertical wire or metallic plate mounted in either the horizontal or vertical plane (or any angle in between) equally well. For a wire the sensitivity is primarily determined by it's length. For a rectangular plate, for all practical purposes, by it's perimeter not its area."The shape and the size of the surface of the antenna PC board seem to be "magic " in the sense that, as soon as you alter these dimensions, the antenna does not work any more"
That is exactly the case. I'll quote Bakker on this one:"then a bigger capacitor will have a bigger aperture and couple more "E" field, thus more signal to the receiver.....but this does not seem to be the case in practice."
"A method was developed to compare the signal to noise ratio of active whip antennas. The carrier of
ONO, Ostend, Belgium, is transmitted on 399,5 KHz. With the 100 cm active whip antenna, the
relative signal strength was -19 dBm. This was the signal read at the SPM-3 with preamplifier. The
antenna noise was measured at 399,15 KHz. The measurement was carried out during daytime to
avoid interferences by remote stations through the sky wave. The antenna noise was about -90 dBm.
The measurement was as follows. The receiver was tuned to 399,5 KHz. The signal from the test
antenna was adjusted for -40 dBm using the RF attenuator. Then at 399,15 KHz the antenna noise
level was determined. Table 1 shows the results of the measurements."
http://dl1dbc.net/SAQ/Mwhip/Article_pa0 ... nglish.pdfIf the whip is shortened, the signal strength decreases gradually. A whip with a length of 30 cm
gives a signal that is 7 to 8 dB lower than with an antenna of 100 cm. The length of the whip does
not affect the ratio between the received signal and the received noise. This is confirmed by the
practice. In the Faroe Islands there are three aircraft beacons coming out in daytime just above the
noise level. They were received on a 30 cm long whip as well as with the 100 cm one.