Re: VLF: Carrier on 4470.005 Hz! - EbNaut test + 970 Hz considerations

[Markus Vester <markusvester@aol.com>]

Hi Stefan,

> Maybe, can i ask for a 424 uHz spectrogram from W and EW?
Here you go - the DL0AO grabber now has a 970 Hz spectrogram below the other narrowband images. Unfortunately the low frequency is more contaminated with a bogus line from 1pps remnants I also don't know how good the directivity of the cardioid really is down there, because the frequency responses from the E-field probe and the ground antenna are probably different.

> I need more power...
Well I think that you could probably run up to around 100 mA at 970 Hz, perhaps by repairing your multistack-coil and loading it with a few kilograms of laminated transformer iron.

Best 73,
Markus

  

-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mo, 28. Aug 2017 12:52
Betreff: Re: VLF: Carrier on 4470.005 Hz! - EbNaut test + 970 Hz considerations

PPS: Sorry, i was wrong. Stacking 2 days means (up to) 3 dB. So we need 16 days for 12 dB. About 8 months to reach DL0AO. That's maybe a bit much. I need more power...

Am 28.08.2017 12:29, schrieb DK7FC:

PS: Maybe even Paul can find something. I remember last year we tried to see a trace on Paul's side, on 2970 Hz when i run 3 kV for 7 weeks or so. But now we saw and know the propagation challenge on 2970 Hz / 101 km. On the 309 km band, the ERP is much lower (abt 27 dB) but probably we are far away from these dips shown in the plots provided by Jim.

Am 28.08.2017 12:17, schrieb DK7FC:

It would be interesting to analyse the different VLF and ULF bands to see where the daily diurnal phase is most constant. That would limit the number of stackable days to get better results. We never tried to stack more than 9 days (that was on 2970 Hz) if i remember correctly.
One day we may need to do that on 970 Hz! I'm working on the next QRO step on that 309 km band! I think i will need +12 dB to get good results at 50 km distance. To reach DL0AO would maybe require another 12 dB, which will not be possible. All in all i may rise the power by 15 dB relative to now. Then stacking of 4 days would help to see something at DL0AO however! Most exciting!
Hmmm, now, when thinking about that: would it maybe work to stack 16 days to see a trace at DL0 AO, now with the 5 kV (3 nW ERP)? That's just about 2 weeks! :-) I got 15 dB in 47 uHz in 27.2 km distance with an E field antenna, also during noisy days.
Markus, what do you think?
Maybe, can i ask for a 424 uHz spectrogram from W and EW? That would give an impression on the diurnal noise and daily variations.
I could set up my modified mains transformer to run 15 mA antenna current at 970.005 Hz for several weeks! Maybe we will see the impossible, beyond our garden fences!