Hi VLF, Last weekend i improved my ground loop antenna by increasing its length from 900m to 1130m, i.e. +25 % of length, which should give about 2 dB more signal from the same antenna current. This
Received here - 900m Ant: T2019-03-31_13:58,+10m: 1.07fT S/N -10.4dB/1Hz 1130m Ant: T2019-03-31_14:12,+10m: 1.30fT S/N -7.6dB/1Hz The signal strength hasn't increased as much as the area has increase
Hello Paul, Thank you. Interesting. For you the difference is 2.8 dB. But the loop points almost fully into your direction. The angle turned from 6 deg to 3 deg, ie. a theoretical gain of G = 20 lg(c
PS: Earlier that day, the same test was done at 5170.1 Hz. But there, the antenna current was different: 900m: T2019-03-31_12:31,+19m at I = 2.74 A 1130m: T2019-03-31_12:57,+31m at I = 2.12 A i.e. th
Received - 900m: T2019-03-31_12:31,+19m at I = 2.74 A: 0.50fT S/N -6.74dB/1Hz 1130m: T2019-03-31_12:57,+31m at I = 2.12 A: 0.51fT S/N -8.22dB/1Hz So 0.51/0.50 = 1.02 and 1130/900 * 2.12/2.74 = 0.97 s
RR, but for the 2.12 A i needed 415 W TX power and for 2.74 A i needed 515 W. So there is still an improvement of 10 * lg(515/415) = 0.94 dB. Further improvements planned... Tnx & 73, Stefan Received
At DL0AO, we produced spectrograms and plots during the 5.17 kHz test last weekend. During the first session with the shorter guiderail antenna, signficant fading and a dip occured, most pronounced o
Hello Markus, VLF, ULF, Thanks for the todays tests and the good cooperation. Amazing what we can do meanwhile, watching smaller variations of the signal levels, which would not be possible from my l
Received at 5170.1 Hz, 2019-04-05_10:39,+35m: 1130m, I=2,39 A, 0.63 fT S/N -5.07 dB/1Hz 2019-04-05_11:19,+51m: 900m, I=2,92 A, 0.63 fT S/N -4.92 dB/1Hz Yes, the same fT in both tests. Then we have 90
Hi Paul, Thanks for your measurements. Good idea to calculate B relative to I. Would be interesting to see how this varies with frequency. BTW i did now actually order one of those: https://www.dhgat
