Réception de Stefan DK7FC sur 137715 Hz le vendredi 24 septembre.
Stefan utilisait une antenne constituée de deux réseaux d'électrodes placées en terre et reliées par 600 mètres de fil à une hauteur moyenne de 4 mètres.
Voici comment Stefan décrit son antenne:
Voici comment Stefan décrit son antenne:
It is a wire, 4 m above ground. It is grounded at the far end, using 20 * 0,4 m loong copper rods, about 1m spaced. The same ground electrode array is near the other end of the antenna. The RF is applied at this point, so between one earth electrode and the wire. RF power was about 100 W in this test.
The antenna was not resonated or matched to 50 Ohm but the PA remained absolutely cold, so all the power (measured on the DC side ( P= 12,5 V * 8,5 A)) must have been applied to the antenna. I will take an Oscilloscope to the antenna soon and will measure the U/I ratio and the phase. Then i can add some C and a suitable step up transformer. If Z=R=50 Ohm i can apply my class E PA as well...
The antenna was not resonated or matched to 50 Ohm but the PA remained absolutely cold, so all the power (measured on the DC side ( P= 12,5 V * 8,5 A)) must have been applied to the antenna. I will take an Oscilloscope to the antenna soon and will measure the U/I ratio and the phase. Then i can add some C and a suitable step up transformer. If Z=R=50 Ohm i can apply my class E PA as well...
Récepteur: SDR LF-100
Ant: cadre monospire CU 2x2 m + préampli différentiel à MOS
