VLF Tests so far:
06/2011 – First interested in VLF Comms, detected DK7FC test with Kite antenna on 8.97KHz – Found a Screengrab here!
2011 – some earth mde tests using 17m spaced electrodes, 1w power, dx ~1km.
2020 – Various Earth Mode Tests upto 4km with ~20W power – 40m spaced electrodes
14/8/2021 – 12:20-15:05UTC ~30W to electrodes 40m apart – 8270.0117
14/8/2021 – 15:35-18:50UTC ~40W to electrodes 40m apart – 8270.0117
15/8/2021 – 07:30-10:30UTC ~80W to electrodes 40m apart – 8270.0117 – 1st ‘Dx’ result to Todmorden, 100km!
20/8/2021 – Installed a new Earth spike to the east, again 40m distance.
20/8/2021 – 17:30-19:45 – ~100W to E/W 40m spacing 8270.0111
21/8/2021 – 09:45-11:45 – ~100W to NE/SW 60m spacing 8270.0111 – Better as expected
22/8/2021 – 09:00-12:00 – ~100W to E/W 40m spacing 8270.0111
8/2021 – DL3JMM carrier received on both 8270 and 5170Hz
28/29/30 /8/2021 – Various tests not logged.
5/9/2021 – GPS Referenced 10MHz oscillator as Tx source now in use, freq=8270.011750. New Matching transformer in use using N30 core.
7/9/2021 – 08:00-11:00 – ~200w to E/W earth loop, visible at Todmorden but weak – No reception at G4FVP 17km away.
8/9/2021 – 08:00-11:00 – ~250w to E/W earth loop – Received by G4FVP 17km to the west of me for the first time!! – Narrow filter used on M0BMU Loop Preamp, Signal is ~8dB/700uHz
9/9/2021 – 08:30-11:30 – ~250w to E/W earth loop – Received by G4FVP. M0BMU preamp in wide band setting has no signal detected but signal is there again with narrow filter selected.
10/9/2021 – 08:30-10:30 – ~250w to E/W earth loop
10/9/2021 – 08:30-10:30 – ~250w to NE/SW earth loop – Same strength at G4FVP as E/W, but NE/SW is longer.
11/9/2021 – 08:00-11:00 – ~250w to NE/SW earth loop – Much weaker at Todmorden (maybe 10dB less!) – Heavy rain overnight before this transmission. Actual problem was that i was using the E/W loop rather than N/S!
02,03,04/10/2021 – Multiple Carrier tests to G4FVP using his 1m square loop and M0BMU preamp
Here’s a spectrum lab long plot of 5 days, my signal visible 4 of them. Clive was using 1m2 Loop and M0BMU Preamp.
09/10/2021 – 09:00 – 1st EbNaut Transmission, 20sec Symbols, 3chars, 8k19A – Received at Todmorden without any problem = Eb/N0 13.3
15/10/2021 – 09:05 – EbNaut Tx, 8270.011749, 8sec Symbols, 3chars, 8k19A – ‘VLF’ message received at G4FVP 17km away Eb/N0=-0.5dB, Nice!
16/10/2021 – 09:00 – EbNaut Tx, 8270.011749, 30sec Symbols, 3chars, 8k19A – ‘DTS’ message received at G4FVP 17km away Eb/N0=7dB
17/10/2021 – 09:00 – EbNaut Tx, 8270.011749, 30sec Symbols, 3chars, 8k19A – ‘DTS’ message
