What are u ai= ming for with this system, 600m or 600km.

g3kev<= /div>

----- Original Message -----

<= b>From: Horst Stöcker

To: rsgb_lf_group@bla= cksheep.org

Sent: Saturday, June 05, 2010 5:20= PM

Subject: VLF: Success with my new= Ground Antenna on Dreamer's Band

Hello,
the 800m Ground Antenn= a Test is still a future project - transmissions planned on 23. to 25.= July from the Erpeler Ley near Bonn.
But today I did the second= Ground Antenna Test at my home QTH. Two copper rods of about 50cm were= directed and splitted in the middle of a 100m line. 10m of RG58 connec= t this point with the equipment in my garage: torroid stepup transforme= r, 300 W car amplifier and my new communication test system as sweep os= cillator betwen 8,7 an 8,9 kHz.
After my disappointing first test= with the 30m base I di not expect too mauch. But the signal was audibl= e in a range of 600m depending on the environment.
Horst DO1KHS/DI= 2AN

Von: mal hamilton <g3kevmal@talktalk.net>
Gesendet: 05.06.2010 17:16:12
An: rsgb_lf_group@blacksheep.org
<= b>Betreff: Re: VLF: Two-Way QSO on Dreamer's Band

Gary
What sort of= strength are u receiving the Alpha signals

This might gi= ve u an idea how strong amateur signals are likely to be by comp= arison

There is not= much information available from UK stations about their receiving = capability

de mal/g= 3kev

=

----- Original Message -----

<= b>From: Gary - G4WGT

To: rsgb_lf_group@bla= cksheep.org

Sent: Saturday, June 05, 2010 2:20= PM

Subject: Re: VLF: Two-Way QSO on= Dreamer's Band

Marcus, Walter, LF,

Well done for your VLF 8.97 Hz 2 - way communication.

Keep up the good work.

Monitoring most of the time here but nothing seen as yet, one day I= may see something.

73

Gary - G4WGT - North West England - IO83QO

On 4 June 2010 21:59, Markus Vester <<= a href=3D"mailto:markusvester@aol.com">markusvester@aol.com>= wrote:

Dear = LF,

=

this morning,= June 4th between 6 and 8 UT, Walter (DJ2LF) and myself (DF6NM)= were able to successfully conduct a two-way contact (aka "QSO")= on 8.97 kHz. The distance between us is 20.2 km, well outside th= e reactive near field zone (lamda / 2pi =3D 5.3 km).

=

Both of us = were using our small backyard Marconi antennas at home, for trans= mit and receive. Walter's antenna has 260 pF at an estimated effe= ctive height of about 5 m. He achieved about 370 mA current, resu= lting in a radiated power of about 5 uW (EMRP). I also got 5 uW= from 270 mA into 240 pF at about 7 m. I resonated the antenna us= ing the same little "yoghurt coil" described a while ago, having= 1.3 henry from 9 x 480 turns of 0.2 mm magnet wire, and a room-t= emperature DC resistance of 820 ohms. Walter used a scaled up ver= sion of this coil, about 25 cm diameter and 60 cm long, consistin= g of seven polypropylene household buckets inserted into one anot= her. Each bucket has 460 turns of 0.4 mm wire on it, about 320 oh= ms total DC resistance. Each of us applied approximately 100 W of "RF" = power from a car-HiFi amplifier.

=

Reception was= done by soundcard, without preamplification. We set Spectrum Lab= to 0.95 mHz FFT bandwidth, with noise blanking on, and samplerat= e tracking based on the German 23.4 kHz MSK signal. We chose to= transmit 30 minute dashes, separated by 15 minute quiet interval= s to allow for FFT processing delay.

=

We employed= a special "micro-QSO" format, which was designed to exchange the= minimum single-bit report and confirmation in only three turnove= rs, each containing a single dash. Station identification was by= frequency alone, with preassigned pairs (8969.92 / 8970.02 Hz fo= r DJ2LF, 8970.0 / 8970.1 Hz for DF6NM). Generally the lower frequ= ency was assigned to a negative response (ie. "not confirmed"),= whereas the upper one is positive ("received ok").

=

DF6NM started= by transmitting a carrier on his lower frequency, from 4:00 to= 4:30 UT. This was indeed seen by DJ2LF, who replied on his upper= frequency from 4:45 to 5:15, reporting positive reception. Then= DF6NM confirmed reception on the upper frequency from 5:30 to 6:= 00. The whole procedure took two hours.

=

Attached are= screenshots from both sides. Unfortunately the QRN level this mo= rning was much worse than we had hoped for, with active thunderst= orms in South Italy, Poland and Belorussia. To my surprise, = our dashes still made it through and were unambiguously visi= ble, with an estimated SNR of 6 to 8 dB. Walter's signal can= actually still be seen between my own dashes on my VLF grab= ber http://www.mydarc.de/df6nm/vlf/vlfgrabber.htm .

=

As far as we= know, this was probably the first two-way amateur QSO on VLF, us= ing truely radiated fields. Another dream came true...
=

Best = regards,
Markus (DF6NM)

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