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Date: Sat, 13 Nov 2010 23:53:07 +0100
From: =?ISO-8859-1?Q?=22Jean-Pierre_M=E9r=E9_=28F1AFJ=29=22?=
 <jpm.f1afj@online.fr>
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Subject: Re: VLF: TX on 6.47 and 8.97
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Hello Markus , LF  ,
I am not well calibrated, I used my other PC for this test (not that of th=
e grabber) tomorrow I will make a control to see of=20
order is this error!
73  qro  Jean-Pierre f1afj


Le 13/11/2010 23:04, Markus Vester a =E9crit :
> Dear LF, Paul,
>
> here's a short summary of today's VLF kite transmission. I'm sorry for=
 the late notice, but the experiment had not been planned ahead, and I was=
n't sure if I could get on at all. Also, the kite I am using (a 0.8 m^2 de=
lta toy bought for 4.99 Euro) is a bit small for this sort of activity, an=
d really requires a good and steady wind.
>
> The QTH was actually at 49.3874 N 11.1692 E, a few 100 meters from the=
 former location reported earlier. The GPS-controlled carriers were on air
>   11:15 - 12:15  6470.000 Hz ~ 50 uW, and
>   12:30 - 13:10  8970.002 Hz ~ 200 uW (EMRP).
>
> Getting on 6470 was easier than expected. I simply used the same "seven-=
bucket" coil, which resonates my 240 pF home antenna to 8.97 kHz. Connecte=
d to the kite wire, the resonance was close enough to 6.5 kHz to be tuned=
 by the ferrite plate variometer. Then the drive for the audio amp was inc=
reased until the onset of corona sizzling at 0.25 A. At that point, the am=
p drew 10 A DC from the car battery and probably delivered around 50 W. Af=
ter connecting mobile internet and staring at Stefan's grabber, I was posi=
tively surprised to find a faint trace there!
>
> For the frequency change, I removed the two bottom coil buckets, which=
 brought the resonance to ~ 8.5 kHz. Then I had to carefully pull the rema=
ining 5 buckets apart, inserting bits of plastic foam material as spacers.=
 Going through a few iterations took about 10 minutes, and I got to "full=
 power" (380 mA, 100W) at 12:30. Unfortunately, the wind had started to ca=
lm by then, and there were several dips during this transmission. Finally=
 at 13:10, the kite landed gently in the grass, and I decided to close dow=
n and pack up early.
>
> Traces from both transmissions were visible on DK7FC's 4.5 mHz "600" win=
dows, and the second one also produced a nice dash on the 0.45 mHz window.=
 It is likely that these signals would be useful for a kite-to-kite QSO on=
 either frequency, using 10 minute dashes.
>
> The screenshot from F1AFJ has an interesting dash before 13:00. The indi=
cated frequency seems a bit high (8970.020 instead of 8970.002), which cou=
ld perhaps be due to a small samplerate calibration error. I am also not=
 sure about the time scale  - judging by the width of the noise blobs, the=
 setting could have been 11 mHz and 10 seconds per pixel. It would be nice=
 if Jean-Pierre could confirm the frequency calibration and scroll setting=
s.
>
> I also carefully inspected the OE3GHB grabber, which runs at 1.4 mHz res=
olution and seems to be very sensitive. It showed an unusually dark period=
 of very low noise between 8 and 11 UT today. But no luck for my transmiss=
ion there yet.
>
> Well, in addition to the technical aspects, being outdoors in the warm=
 wind was again a rewarding and enjoyable experience.
>
> Best 73, and thanks again for the interest.
>
> Markus (DF6NM)
>
>
> From: Markus Vester
> Sent: Saturday, November 13, 2010 2:19 PM
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: VLF: TX on 6.47 and 8.97 - QRT
>
>
> Sorry folks, I had to shut down at 13:10 due to lack of wind. Many thank=
s for looking!
>
> Best 73,
> Markus (DF6NM)
>
>
>
> From: Markus Vester
> Sent: Saturday, November 13, 2010 2:08 PM
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: VLF: TX on 6.47 and 8.97
>
>
> Hi Stefan, thanks for the observation! I am approximately at 49.3851 N=
 11.1727 E. After a bit of fiddling with the coil, the carrier is on 8970.=
002 since about 12:25. I will try to stay on till 14:00, but there are a=
 few lows as the wind has calmed down a bit.
>
> 73, Markus
>
>
>
> From: Stefan Sch=E4fer
> Sent: Saturday, November 13, 2010 1:50 PM
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: VLF: TX on 6.47 and 8.97
>
>
> There is a trace now coming up slightly above 8970 Hz in the DFCW-600 wi=
ndow :-)
>
> Markus, what is your exact locator? http://no.nonsense.ee/qthmap/  Let=
 us see where you are currently :-)
>
> 73, Stefan
>
> Am 13.11.2010 13:16, schrieb Stefan Sch=E4fer:
>    Wow! Hi Markus,
>
>    Good luck!! Yes, the wind is very strong indeed. For my kites it is=
 almost to strong...
>    With your kite you should easily be visible in the 6000er window on=
 8970.
>
>    OOOH! I just looked on my 2nd VLF grabber http://www.iup.uni-heidelbe=
rg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html and saw your trace in DFCW-600!
>    Congratulations Markus!!!! This is the second amateur radio station=
 at all who reaches the far field within the 46km band :-) i estimate 8 dB=
 S/N maybe 10. Great!!!
>
>    So DFCW-600 on 8970 should be no problem later :-))
>
>    Who else of the group is monitoring? It would strongly interest how=
 Markus is received at other locations :-)
>
>    Best 73 and wish FUN!!
>
>    Stefan/DK7FC
>
>    Am 13.11.2010 12:54, schrieb Markus Vester:
>      Nice wind here in Nuernberg, and I'm back on the /p QTH with my sma=
ll kite (100m wire, kite currently about 60m up). Since 11:15 I am sending=
 a carrier on 6470.00, trying to generate a small peak on DK7FC's second=
 grabber. Max current into the thin wire is about 0.25 A. After one hour=
 at 12:15, I intend to switch to 8970.002 Hz, where I can radiate about 0.=
2 mW at 0.4 A.
>
>      Best 73,
>
>      Markus (DF6NM)