Stefan DK7FC transmitted at 6 aptil 2019 20:25 UTC at 2970.1Hz. The TX power was 487W into a 1130m ground dipole antenna. The ebnaut transmission parameters were:
f = 2970.1 Hz
Start time: 06.APR.2019 20:25:00.3 UTC
Symbol period: 6 s
CRC bits: 16
Antenna current: 2.4 A
Duration: 02:04:48 [hh:mm:ss]
The signal was received by Jacek / SQ5BPF in Warsaw/ Poland KO02md, at a distance of 976km!
After the filtering and noise blanking was optimised, the signal could be decoded:
[email protected]:/stuff2/sq5bpf/vlf_stefan2$ vtcat -p < stefan_2970_1 | vtfilter -a th=4 -h bp,f=2970,w=2200 > ../vlf_stefan2/pliktmp6
[email protected]:/stuff2/sq5bpf/vlf_stefan2$ vtblank -v -d0.0007 -a20 -t 50 < pliktmp6 | vtmult -f 2970.1 | vtresample -r 240 | vtresample -r 10 |vtraw -oa | ebnaut -dp16K21A -r10 -c2 -v -k16 -S6 -N7 -PS -L 50000
vtblank: selected channel: 1 = -:1
vtblank: channels: 1, sample_rate: 48000
vtblank: hfactor: 0.000e+00
vtblank: afactor: 20.000
initial reference phase -89.4 amplitude 7.496e-04
phase 0 0 0 0 0
vtblank: end of input
vtblank: dropsum 0 64750004, nfp 359999999
vtblank: dropfactor 0 1.799e-01
found rank 14143 ber 4.2548e-01 Eb/N0 -2.5 M -2.143712342e-02 ph 0 0,0,0,0 [DK7FC/P]
carrier phase: -10.6 deg
carrier Eb/N0: -0.4 dB
carrier Es/N0: -15.33 dB
carrier S/N: 15.63 dB in 133.5 uHz, -23.11 dB in 1Hz, -57.09 dB in 2.5kHz
The message was: DK7FC/P
Link to Stefan’s email:
Encouraged by our last experiments with ground dipoles we decided to do a transmit experiment with this antenna on VLF 8.270kHz, 36km (36000m) wavelength. Thanks to Fab LAB Trójmiasto we had a great location on the see on a cliff near the Baltic Sea in Gdynia. Our goals for this experiment were:
- Try transmitting from a ground dipole on VLF
- Assess the field strength near the sea
- See if it is possible to reach greater distances with relatively simple equipment and low power.
- Test a broadband transformer for VLF-LF-MF
Continue reading “VLF transmit tests from a ground dipole”
Joe VO1NA transmitted on 21 december 2017 at 8270.0075Hz.His transmission was succesfuly received in Warsaw (RX Jacek/SQ5BPF), at a distance of about 5100km. This is the first succesful reception of a signal from Canada in Poland at 8270Hz.
Continue reading “First succesful transmission on 8270Hz between Canada and Poland”
In 22 and 23 april 2017 Stefan DK7FC did additional test ebnaut transmissions on 6470Hz. Similar to the previous tests, the transmission was decoded as usual by Paul Nicholson (850km) and also by Jacek SQ5BPF (900km). Continue reading “Next tests in the 6470Hz band”
Stefan DK7FC has been recently transmitting on 6470Hz (46km wavelength) from a stationary antenna between two buildings.
The Ebnaut transmissions were received by Paul Nicholson (England) and Jacek SQ5BPF (Poland) at a distance of 900km (IN49IK to KO02MD).
Continue reading “6470Hz transmission by DK7FC succesfuly received at SQ5BPF (900km distance)”