Re: VLF: 4470.005 Hz + 4469.9883333 Hz

[Markus Vester <markusvester@aol.com>]

There seems to be a peak on the right frequency but not much above the noise. QRN has been building up this afternoon, and I have switched off the carrier now at 18 UT.

Best 73,
Markus


-----Ursprüngliche Mitteilung-----
Von: Markus Vester <markusvester@aol.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 26. Aug 2017 14:35
Betreff: Re: VLF: 4470.005 Hz + 4469.9883333 Hz

Hi Stefan,

the number entered into the signal generator is 4469.98833330000, i.e. 1/30 uHz below nominal 1/3. Can you tell the difference? If I would go on transmitting forever it would accumulatre to approximately one cycle per year. However in reality it would not, because the phase is pulled back on track by SpecLab's midnight reset.

Good traces on the DL0AO grabber already, but reaching Heidelberg will be a much longer shot. I think the minima from your PSK are deep enough, as long as the QRN doesn't activate the noiseblanker too often.

Markus
 


-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 26. Aug 2017 13:00
Betreff: Re: VLF: 4470.005 Hz + 4469.9883333 Hz

Hello Markus,

Are you on 4469.9883333 or on 4469.9883333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333 Hz ? :-)
Sorry, it looks like my nulls in the spectrum are not as low as expected. I would stop my transmission on that band but it looks like i need several more days to reach a proper SNR on Pauls side. Last night has been very noisy again.

That leads me to the question if there can be a propagation advantage on 1600 Hz, which triggers the resonator between earth and the D layer of the ionosphere at night? Probably we can't expect much from an E field TX antenna. What will happen?

73, Good luck.
Stefan

PS: Increased from 150 mA to 155 mA here, about 0.3 dB more, which can already decide between a false and a correct decode


Am 26.08.2017 11:46, schrieb Markus Vester:

Started a carrier on 4469.9883333 Hz since 9:30, antenna current 0.17 A.

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Markus Vester <markusvester@aol.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 25. Aug 2017 15:25
Betreff: Re: VLF: Carrier on 4470.005 Hz! - EbNaut test

Hi Stefan,

no decodes from yesterday Aug, 24, likely due to the much increased QRN already in the afternoon. I also tried to combine 23rd and 24th and still found the correct decode in the list, but with deteriorated SNR.

Thanks for starting the slow 28 uHz window in Heidelberg! If you like, you could perhaps shift or split the display range to show a slot around 4469.988333 Hz, i.e. the gap 16.667 mHz below your EbNaut center frequency. However I won't transmit today, due to high QRN background and predicted thunderstorms tonight.

Best 73,
Markus  

-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 25. Aug 2017 11:52
Betreff: Re: VLF: Carrier on 4470.005 Hz! - EbNaut test

Hello Markus, VLF,

Now there is a 28 uHz Spectrogram on my grabber, http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
Scroll rate is 2 hours per pixel.
You can see my own carrier on 4470.005 Hz which is running between the EbNaut messages.
Currently the EbNaut message is running for the 3rd time.
Yesterday it was quite noisy again. I'm curious to see if Paul can decode the message with 3 stacked days.
I find that most fascinating! Stacking daily transmissions is only possible on VLF (or ULF/ELF probably?). So everyone could try to transmit there, even with an 'average' LF transmit antenna. The coil and the stable frequency generation seems to be the problem however. Actually we need some more public relations, more spread information and motivation for potential VLF newcomers. As soon as a critical number of TX and RX stations has been overcome, it can be a self-running movement. The RX capabilities of DL0AO are certainly a new valuable contribution to the RX sites.

As soon as the message is decoded on Pauls side, i want to rise the antenna current to 170 mA (~ + 1 dB) and try a longer message, maybe 20 characters or so. There is enough time to run the experiment now...

73, Stefan

Am 21.08.2017 15:06, schrieb Markus Vester:

Thanks Stefan! Distance between DF6NM and DL0AO is 48 km.

Yes a slow window from your tree might possibly receive my signal on 4470, albeit marginally, with perhaps 10 to 12 dB in 31 uHz. Unfortunately I won't be able to do long daytime transmissions before the next weekend.

Best 73,
Markus

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