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Re: LF: A CME hit this morning

To: [email protected]
Subject: Re: LF: A CME hit this morning
From: Steinar Aanesland <[email protected]>
Date: Sun, 17 Mar 2013 21:59:50 +0100
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Hi Markus

Thanks for your very interesting comment as usual :)

LA5VNA Steinar

Den 17.03.2013 17:40, skrev Markus Vester:
> 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)
> From: Steinar Aanesland 
> Sent: Sunday, March 17, 2013 5:07 PM
> To: [email protected] 
> 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:
>> 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: 
>> 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?

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