Re: VLF: Re: Transmitting 250W at 8970 Hz on a 600m spaced earth antenna

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Thanks Stefan. I'll update the sub-9kHz page and table with these results later.

73s
Roger G3XBM

2010/8/29 Stefan Schäfer <schaefer@iup.uni-heidelberg.de>

Hi Roger,

As written below, the distance was 49,6 km. The signal was detected by Michael Oexner (no callsign) in JN49BF ,who sent a mail with a screenshot yesterday. The reception was a single dash, that absolutely matches time and frequency (compared to my grabber that is tracked by GQD (22,1 kHz)). As usual, a "message" such as "73" or "cu" or "fb" or something like that is preferable, so we will do further tests. It is no problem to do those tests since the antenna can just be connected, even during wind and rain :-)

BTW, if my signal was 35 dB above noise in 5 km at 250 W, i could see my signal even with 2,5 W :-)
It seems, the QRN comes down below -90 dB in the morning hours on many days, seems to be nothing special in the "DX" period :-)


Eventually i will try to receive my own signal at the QTH of my parents, about 35 km distanced, directly orientated to the antenna.

Any questions else?


73, Stefan/DK7FC

Am 29.08.2010 09:15, schrieb Roger Lapthorn:

Hi Stefan,

Please summarise Saturday's tests with the earth electrode antenna on 8.97kHz. The above emails leave me a bit confused about who saw the signal (?) and at what distance.

I believe you are going to repeat the tests to get a better confirmation of the result?

73s
Roger G3XBM

2010/8/28 Stefan Schäfer <schaefer@iup.uni-heidelberg.de>

Hi Michael, Markus, VLF,

Well, time and frequency absolutely corresponds with my transmission so i would say it is a positive reception. Anyway i think we should do the test again, sending a message or a some charakters to better confirm the reception. Maybe DD7PC is QRV in DFCW-600 (abt 4 mHz) again the next time?

The distance of the todays experiment is: 49.6 km.

My antenna bearing is 9/189 deg, the QTH of Michael is in an angle of 54 deg to this antenna. So, not an ideal orientation, if the antenna acts like a loop, but a weak reception anyway. The picture shows the locations of TX and RX. The yellow line is the distance, the white line is the antenna orientation. TX power was 250 W, just like yesterday. Antenna current will be measured in the next experiment...

Tnx to Michael for the effort to catch that signal (Markus as well).

73, Stefan/DK7FC

PS: Markus, tnx for the screenshots of the DFCW-3 message :-)

Am 28.08.2010 13:09, schrieb Michael Oexner:

Hi Markus, Stefan and list,


 

Since 10:25, Stefan is on air again with his ground loop. Signals
on his own grabber are even better than yesterday, perhaps due to
somewhat lower QRN. I am also looking here but don't have much hope,
as the TX antenna is N-S oriented and Nuernberg is 180 km due east.
 Good luck,
Markus (DF6NM)
   

Have a close look at the enclosed screenshot... what would you say?

There is a weakish line on 8969.735


 

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G3XBM   GQRP 1678    ISWL G11088

-- 
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM   GQRP 1678    ISWL G11088