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Re: LF: A CME hit this morning

To: <[email protected]>
Subject: Re: LF: A CME hit this morning
From: "Markus Vester" <[email protected]>
Date: Sun, 17 Mar 2013 17:40:55 +0100
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Steinar,
 
thanks for this info. I think the signal which was visible in Chris' and my µHz grabbers around 12 UT was a qrss transmission from RN3AGC.
 
According to my understanding, from the Doppler shift you could estimate the vertical velocity of the layer but not the height. At vertical incidence, 0.1Hz / 138kHz  would correspond to 0.36e-6 c ~ 108 m/s. However the movement would have to be faster when the same shift was observed with oblique incidence, so the interpretation depends on the distance between TX and RX. 
 
I don't think Doppler on a narrowband signal alone will let you derive the altitude of the layer, although in general LF signals will normally not be able to penetrate much beyond 100 km above ground. In the "SXV ripples" observations, there was an obvious frequency dependence across the 100 Hz wide spectrum, which seemed to indicate an unusually large delay of about 10 milliseconds. This is still a riddle as it can't easily be explained by vertical multihop propagation. So I believe there must have been a horizontally displaced and moving scattering center, perhaps reminiscent of an Aurora reflection. But of course this is just speculation.
 
Best 73,
Markus (DF6NM)

Sent: Sunday, March 17, 2013 5:07 PM
Subject: Re: LF: A CME hit this morning

Hi Markus

My IC-R75 (X-tal oven) is in REV CW mode and the pitch is 600Hz .
My frequency scale is calibrated after the time station on 77.5KHz
(599.90Hz in the waterfall).  LA4ANA's beacon is 7.6Hz over the pitch
freq in the waterfall. I hope I am not thinking 180 degrees wrong now,
but this gives me 137787.6.

Markus, is it possible to estimate the hight of reflection layer , when
you know the frequency and the doppler shift ?


LA5VNA Steinar
loc:JO59jq


Den 17.03.2013 11:15, skrev Markus Vester:
> Steinar,
>
> thanks for reporting this! The 0.1 Hz Doppler shift is remarkable. Is your frequency scale upright or inverted?
>
> On a several occasions a few years back, I observed still unexplained "ripples" on SXV 135.8 kHz, which seemed to indicate a delayed component with a similar-sized Doppler shift:
> http://df6nm.bplaced.net/LF/sxv_ripples/sxv_ripples.htm
>
> What is strange is that according your screenshot the shifted trace appeared from 4:15 to 4:45 UT, whereas the Boulder magnetometer shows a magnetic disturbance starting not before at 6:00:
> http://www.swpc.noaa.gov/rt_plots/bou_12h.html
>
> BTW I wonder if LA4ANA's beacon would be detectable on one of our 137780 Hz microHz grabbers here. Do you know his exact frequency, and whether the carrier is phase continuous?
>
> Best 73,
> Markus
>
>
> From: Steinar Aanesland
> Sent: Sunday, March 17, 2013 10:40 AM
> To: *[email protected]
> Subject: LF: A CME hit this morning
>
>
> I think I picked it up with my 137Khz grabber. I am monitoring Robert
> LA4ANA on 137780. It is ground wave between us, but I think I can see an
> sky wave refection also when the storm hit the earth. What do you think?
>
> https://dl.dropbox.com/u/16381257/qrss60_multipath.jpg
>


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