Stefan,
Plots indicative of frequency spreading of VLF signals in a geomagnetic storm
(better images in the link in the previous message; rendered these as .gif to
stay under 500kB)
73,
Jim AA5BW
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of DK7FC
Sent: Friday, March 24, 2017 5:49 PM
To: [email protected]
Subject: Re: ULF: New carrier near 2970 Hz...
Hi Jim, ULF,
i wondered why the trace at IK1QFK in 5 wavelengths distance becaome so blurry
in the recent days.
See http://www.webalice.it/rromero/live_cumiana/last-LFtest_2970.jpg and use a
zoom function :-) The SNR of the next upper bin (5.06 uHz
'higher') reached the same levels and sometimes even more! The overall SNR was
increased significantly, to up to 14 dB.
Could this have to do with enhanced sky-wave propagation? During the same time
the signal became smaller at Paul's location...
I'm looking forward to the new VLF/ULF grabber at DL0AO, the are having
progress in beg steps! Impressive.
It will certainly help to permanently inspect the signal out of different
locations...
73, Stefan
Am 23.03.2017 22:52, schrieb [email protected]:
> Geomagnetic K-index elevated March 21 through March 23, approximately 3<
> Kp< 4 but higher in Europe with levels at Wingst and Niemegk varying by 50nT
> to 80nT at times during that period.
>
> Mentioning this in case it applies to received phase of the 2970 signal.
>
> But now wondering if this disturbance should be thought of as cause or
> effect, with 2970 TX currents having grown to 180 mA.
>
> Jim AA5BW
>
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of DK7FC
> Sent: Wednesday, March 22, 2017 9:15 AM
> To: [email protected]
> Subject: Re: ULF: New carrier near 2970 Hz...
>
> Hi Paul,
>
> Interesting. Do you also use the noise normalisation function which proved to
> be useful in recent stackings on 5170 Hz?
>
> Still a few weeks before the 6 channel input soundcard for the Raspi
> appears...
>
> 73, Stefan
>
> Am 22.03.2017 11:25, schrieb Paul Nicholson:
>
>> Stefan wrote:
>>
>>
>>> Isn't it extremely unlikely that this is something elso than my
>>> signal??
>>>
>> Well I don't know. It would be an extraordinary achievement for your
>> 2970 signal to reach this far. It needs a result
>> that can stand up to scrutiny. I'd like to do some more
>> work with it to get an unequivocal detection at 5 sigma.
>>
>>
>>> I'm going to run the carrier another few days, at least until
>>> friday,
>>>
>> A few more days signal will help. Adding 21st didn't
>> improve the peak, nor did the blanker settings I left running last
>> night.
>>
>> For these runs I am blanking each antenna channel independently, then
>> mixing and phasing. Usually I do the mixing first and blank the
>> composite signal.
>> While one channel is blanked and another isn't, the mix is wrong.
>> That ought to be worse than blanking after the mix. With less than
>> 5% blanking factor it might not be much of an issue either way.
>>
>> I can also look again at your previous 2970 tests, stacking the same
>> 14:00 to 19:00 window.
>>
>> --
>> Paul Nicholson
>> --
>>
>>
>
>
Subionospheric VLF measurements - geomagnetic storms - Inan 2005 - Fig 5....gif
Description: GIF image
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