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Re: ULF: Transmission announcement for 2970 Hz

To: [email protected]
Subject: Re: ULF: Transmission announcement for 2970 Hz
From: DK7FC <[email protected]>
Date: Thu, 02 Feb 2017 19:54:06 +0100
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We are in 881.2 km distance, as you say. That is 8.72 lambda on 2970 Hz (101 km band). If i would switch my large coil in series with the small coil for 5170 Hz, the overall inductance would be 8 H! I could then resonate at 2.57 kHz (117 km band :-) )
That's just QSY by 400 Hz, the 'distance' between 2 CW QSOs but a wavelength difference of 15700 m!

The distance between us, expressed in wavelength, would be reduced to 7.55 lambda, on 2.57 kHz. Maybe the propagation is completely different there, on 117 km?

Or, another quick game: The 5170 coil in series with the 8270 coil would resonate at about 4.39 kHz, or 68 km :-) That should work without many problems and i could run 225 mA there, even with less HV stress to both of the coils.

I can tell you i love to transmit down there! It's like walking on the moon!!!! It was already fully worth to wind these coils. I already miss to wind another one.

73, Stefan

Am 02.02.2017 13:48, schrieb DK7FC:
Hi Paul,

But the data of the transmissions that happened so far are saved on another PC, right? Would be a pity if they are lost.

I risked to transmit during the rain last night. the coil is protected against rain with a simple trash bag. The antenna current dropped to a level very close to the limit, but obvioulsy not below. Today a visual inspection showed that a few drops seem to be completely uncritical. No HV erosion visible. I know how that looks from LF! 20 kV on 2.97 kHz is a different thing than 20 kV on 137 kHz!!

Now i set to current to 160 mA, an increase of 0.56 dB...

No trace at all on Renatos 5 uHz spectrogram Each update will be exciting :-)

73, Stefan

Am 02.02.2017 12:21, schrieb Paul Nicholson:

A good signal here Uwe.

> Meanwhile i'm transmitting since 35 hours a stable
> carrier on 2970.000000 Hz :-)

I have just managed to install another 2TB scratch disc
in my workstation - at last.  Have been waiting some time
for the chance to shut it down.

Now I can really get to work on those elusive 2970 Hz signals!

Paul Nicholson

Am 01.02.2017 17:42, schrieb DK7FC:
...transmission still running. The ex forecast shows a slight rain in an hour. I disabled the ALC and set the safety limit to 10 mA. If the coil becomes wet, the resonance will drop, the antenna current will drop. After 3 seconds below 140 mA the carrier will stop. But maybe i am lucky and the rain will not set in here...

73, Stefan

Am 01.02.2017 00:29, schrieb DK7FC:

Since 23:25 UTC i'm running 150 mA antenna current again on 2970.000000 Hz.

If the wx permits, i'll run it for 24 hours or so...

73, Stefan

Am 30.01.2017 15:08, schrieb DK7FC:
Hi Paul, ULF,

Am 29.01.2017 18:26, schrieb Paul Nicholson:

Stefan wrote:

> From the known decoded EbNaut messages, what was the SNR at
> Renato or on your side?

Nothing detectable here or at Cumiana so I can't answer the
question of how many days need stacking.  Until there is some
glimpse of a signal, it is completely unknown.  I can only
estimate a lower limit.
Yes, we don't even know if the night could be better than the day.

Between 2016-06-26 13:00 and 2016-07-31 08:00 you transmitted
carrier with 30mA antenna current.  I received and stacked
over 34 days of carrier (about 15dB stacking gain) with no
sign of signal.  You estimated 100nW ERP.

Now you can do 150mA current - about 14dB gain over July's
signal.  Plus, improvements here to filtering and blanking
may add 2 or 3dB more.
Plus the lower QRN!

We can in two days exceed the stacked signal for the whole
of July.  Also with your higher ERP I can see the signal each
day at Bielefeld to check the phase.
Yes, Wolf's RX is a nice feedback channel for the daily tests.
I think we should try some daytime carrier repeats.  Already we
know there is nothing after 2 days so we will need at least
4 days to get a hint of signal and then at least 10 days to
collect enough signal for some measurements.  It is surely
certain that we will eventually pick up the signal after
enough days.
Yes, more adding is the only way to find out what happens between QRB of  3 and 5 lambda, and 8.8 lambda!

I assume you have saved the data from Cumiana to add the signals that i transmitted so far at 150 mA?
That was:
Jan, 20th, 8...20:00 UTC 2970.000 Hz
Jan, 21th, 8...17:00 UTC 2970.000 Hz + 17...20 UTC 269.9975 Hz
Jan, 22th, 8...14:45:20 UTC 2970.000 Hz, reconstructed carrier of EbNaut (8K19A, CRC16, 7ch, 40s, message: 'F/DK7FC')
Jan, 24th, 8... 16:00 UTC 2970.000 Hz, reconstructed carrier of EbNaut (16K25A, CRC18, 3ch, 30s, message 'ULF')
Jan, 25th, 7... 16:20 UTC, 2970.000 Hz, reconstructed carrier of EbNaut (16K25A, CRC16, 5ch, 30s, message 'DK7FC')

That's already 42 hours in daylight (8...17 UTC), a peak shown in 6.6 uHz. And there is nothing at all?
Can we assume that Renato's RX has the full sensitivity on 2970 Hz? The sferics always appear very strong. I clearly expected to see Markus on 8270 Hz in JN38OO, even with my resonated antenna, because the sferics still looked so strong. But there was not a trace at all! It is hard to imagine that Wolf can decode the messages 'easily' and Renato can't seea faint peak. But maybe, that's how it is. I should do a holiday weekend again, in 4 lambda distance...

If the wx permits, i will run a carrier tomorrow on 2970.000 Hz between 8...17 UTC.

73, Stefan

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