LF: Tweeks at VE7TIL

[Markus Vester <markusvester@aol.com>]

Hi Scott,

 

thanks for sharing this fascinating tweeks recording.

 

I ran your wav through spectrogram, and have attempted to graphically estimate the source distance from the knee delay. The cutoff frequency of the ionospheric TE/TM modes was 1.80 kHz, related to a reflection height of 83 km. The arithmetics of multiple hops show that the time between the start of the tweek and the crossover at fc*2/sqrt(3) = 2.08 kHz should be identical to the groundwave propagation delay.

 

In your recording, there appeared to be two populations of tweeks, one at approximately 7 ms delay (2100 km), and the other at twice that range (14 ms, 4200 ms). If you recorded two channels with orthogonal loops, you could take bearings and directly plot the discharges on a map.

 

Best 73,
MArkus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Scott Tilley <sthed475@telus.net>
An: rsgb_lf_group@blacksheep.org; Discussion of the Lowfer (US, European, &amp; UK) and MedFer bands <lowfer@mailman.qth.net>
Verschickt: Do., 12. Mai. 2011, 4:47
Thema: LF: VE7TIL 2200m Grabber back online...

Hi All 
 
Repairs to the grabber have been made and the system is back in full operation. 
 
Sorry for the outage as what started as a limited experiment on VLF turned into a rapid departure from reality! All this drama caused by a single MAV-11 going belly up... 
 
Stay tuned for a VLF grabber in the coming days as I'm pleased to report that I'm having outstanding results with my new VLF RX system. Just a matter of settling it into a long term home in the shack as its presently a kitchen table project... 
 
VLF TX project is proceeding and I hope to do some tests shortly... 
 
For those interested here's a link to a recent 'tweek rain storm' I recorded a couple of nights ago: 
http://dl.dropbox.com/u/15916951/VLF/VLF_distant%20constant%20tweaks_6.wav 
 
Here's some screen grabs in ever longer temporal detail... 
 
http://dl.dropbox.com/u/15916951/VLF/tweaks_10509221705.jpg 
http://dl.dropbox.com/u/15916951/VLF/tweaks_10509222226.jpg 
http://dl.dropbox.com/u/15916951/VLF/tweaks_10509223859.jpg 
http://dl.dropbox.com/u/15916951/VLF/tweaks_10509224138.jpg 
 
Enjoy ! 
 
73 Scott 
VE7TIL CN89dk 
http://www3.telus.net/sthed/argo/ 
 
PS - Thanks Wolf for the mods to SL! They work great! 
 

VE7TIL_tweek_distance_evaluation.jpg
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