No luck with OE3GHB and G3XIZ on 8.97kHz today

Despite having my antenna and receiver system well optimised and running a Spectrum Lab configuration file allowing very sensitive detection (DFCW6000), nothing (so far) was identified from either Gerhard OE3GHB or Chris G3XIZ on 8.97kHz today. So far, the only station I have "seen" on VLF is DK7FC/P back in December. Since then I've improved the set-up. G3XIZ didn't have his "balloon extended" antenna in place, so he could be several dB stronger the next time he tries again.

Dreamer's Band activity around 8.97kHz

In the last few days OE3GHB and OE5ODL have been testing close to 8.97kHz with their signals (from home QTHs) being received at considerable distances across Western Europe. DK7FC was planning his 10th kite VLF test this weekend but has had to postpone this until Jan 29/30 because of the weather. My grabber is currently looking around 8.97kHz and seeing a strong signal, although I suspect this is a locally generated interferer. See http://dl.dropbox.com/u/15047843/xbm_grab.jpg for the grabber as it updates. This is not on all the time, just when I am testing or listening.

A 4th UK station with VLF NoV

Just received this from Gary G4WGT:

"Today I received my SRP from Ofcom to carry out research and experiments on the 9kHz band. The NoV is effective immediately and expires on 10th January 2012. The allocated frequency, power and additional conditions are the same as for other UK 9kHz operators, ie. 8.700kHz to 9.100 kHz with a maximum of 100mW (-10dBW) e.i.r.p. I am not ready to transmit a signal yet but it will be quite soon. I will make an announcement through the usual channels.

73  Gary - G4WGT"

Improved E-field probe for VLF

Today I made an improved version of my VLF E-field probe. The first hi-Z FET input stage now an amplifier with an 8-9kHz tuned circuit in the drain. Sensitivity is now much better than before with strong Alpha beacon reception. It works well with the 80cm loop too and with the large TX loop in the garden via a step-up transformer. I'm looking forward to further tests by DK7FC and G3XIZ on 8.97kHz as my sensitivity is now better.  I hope to test this out in the field with my 8.76kHz transmitter over the weekend.

VLF success at last for G3XIZ (37km on 8.97kHz)

Chris G3XIZ achieved some VLF success today when his 50m high balloon supported vertical driven with around 50W was copied at up to 15dB S/N by M0BMU at a distance of 37km. Mode used was QRSS600. This is a new UK record for an amateur VLF transmission and is the first confirmed "far field" radiated signal. Well done Chris.

M0BMU estimated the ERP as follows (from a posting to the LF-reflector by Jim):

"I made an estimate of the field strength of your signal by injecting a test signal at a known EMF into the loop antenna, and comparing with the level of your signal. The received FS at the strongest point (around 1330utc) worked out to be 1.8uV/m. Taking the distance between our locations as 37km, your ERP would have been 87uW. The SNR at best was around 15dB, making the noise level 0.32uV/m in the FFT noise bandwidth of 2.1mHz, or a noise density of 7uV/m per sqrt(Hz)


Assuming a 50m vertical wire (heff ~ 25m),  Rrad of your antenna at 8.97kHz would be 880micro-ohms. Assuming 2.62dB directivity for an electrically short monopole compared to a dipole, and Iant of 200mA, the calculated value of ERP would then be 64uW. So there is reasonable agreement between these two calculations, the difference only being 1.3dB."

G3XIZ on 8.97kHz today

Chris, G3XIZ was testing on the Dreamer's Band again today and I was monitoring some 34km to the east. Unfortunately, this attempt was also unsuccessful with no copy here in East Cambridgeshire.

VLF real DX: 2873km on 8.97kHz

Yesterday, Sat Dec 4th, DK7FC's VLF signal was copied by 4X1RF at an astounding distance of 2873km. Signal levels suggest that transatlantic reception may indeed be possible in the near future. Many other stations also copied Stefan's signals on various VLF frequencies yesterday. Congratulations to Stefan and everyone else who managed to copy his signal.

DK7FC's 8.97kHz signal copied today (and in Israel!)

Weak signal around 8970.0Hz

Today I managed to weakly copy DK7FC's latest test transmission on 8.97kHz using my 20m spaced earth electrode and small FET preamp. Spectrum Lab, locked to a VLF MSK transmission helped by allowing me to look at precisely the right frequency. Distance is 648km. Stefan's signal was also copied in Israel, quite remarkable DX.

DK7FC on 8.97kHz this weekend

Stefan DK7FC is making preparations for a further test transmission on 8.97kHz this weekend. Saturday is his preferred day but if winds to support his kite antenna are too low, it may be Sunday. As usual, he will use very slow QRSS and DFCW.  During his last transmission he was received at 1310km and in a number of European countries.

First Norwegian VLF amateur transmission

From Jan LA3EQ:

"First succesfull transmission on 8.760kHz using WSPR mode in Norway using 40 meter longwire and only speaker output from the pc soundboard as a transmitter and a 12volt to 220v transformer as impeadence "antenna matching" transformer..  Several WSPR spots of -2dB to -7 dB. distaince only 50 meters, but it is a start. Next try will be with earth dipole and 10 watts and an active e-probe antenna on receive."

VLF kite transmission by DF6NM

DF6NM's signal in the UK

Marcus DF6NM carried out another successful VLF test yesterday on 8.97kHz (200uW ERP) and 6.47kHz (50uW ERP) with reception by Paul Nicolson in Todmorden UK.  Marcus is the second German VLF amateur to be copied at this distance.

Looking for G3XIZ on 8.9719kHz VLF

Looking for G3XIZ on 8.9719kHz - maybe a faint trace??

Between 2000 and 2200z this evening G3XIZ has been transmitting on 8.9719kHz VLF with his Marconi vertical and about 20W RF into it. I've been monitoring with my earth electrode antenna, a preamp/filter and a PC running Spectran on 0.17Hz resolution, but don't think I've seen any sign of him.

Stable, simple, stand-alone, 8.970kHz source?

What do people think is the simplest way of generating a stable 8.970kHz (kilohertz) frequency that does not require a PC when running? I thought of an HF crystal divided down by 256, but have you tried to buy a "made to order" crystal lately? I need this for my VLF tests this coming winter.

M0BMU receiving DK7FC's 8.97kHz signal 10dB S/N

Jim reports that Stefan's DK7FC's 8.97kHz test signal is visible at 10dB S/N in Tring UK this morning. He is also visible on other grabbers in Europe. This is an excellent report and further encouragement for those of us taking our first (QRP) steps on the 33km band.

Further 8.97kHz test this Saturday

DL7FC, Stefan, is planning another VLF kite antenna test this weekend Oct 23rd. I am assuming he will be on 8.97kHz again.

8.97kHz DX tests Oct 2nd 2010 (DK7FC)

Stefan's latest tests are going well with copy at 902km (Poland) and in Holland and the UK. His signal is stronger than ever before. Well done Stefan. Some stations right across Europe and even in North America are watching.

More German VLF radiated DX tests Sat October 2nd

From Stefan DK7FC:

Dear LF/VLF,

My next VLF kite experiment will be tomorrow, saturday, 2nd october :-) After my request to the german air traffic control i got a very kind telephone call at 01:30 AM and later i got the permission to go up to 200 m above ground. See attached mail if of interest for you.

So, if there will be enough wind and no rain, i will try to become QRV at arround  8 UTC.

Tomorrows program:

- (after some resonating tests): Transmitting a short message on 8970 Hz, mode: DFCW-600, hoping to be visible on several receivers in the EU region and maybe Canada and USA (!?)
- Transmitting a CW message (in 12 wpm and in 25 wpm), hoping to be audible at Bernd/DF8ZR (16 km range) and my grabber (40 km)
- Maybe trying a xband QSO 9kHz/144 MHz to DF8ZR
- Transmitting a message on 6470 Hz, mode: DFCW-600, hoping to be visible at many RX, especially Renato Romero who has set up a grabber page at http://www.vlf.it/cumiana/livedata.html
- Transmitting a 30 minute carrier on 8970 Hz which allows long time integration. Paul Nicholson wants to try to record the VLF audio stream from Florida and maybe extract my signal.

- Being visible at PA3FWM at the university of Twente who set up a grabber page at http://websdr.ewi.utwente.nl:8901/grabber.html
- Being visible at SQ5BPF and maybe a russian station?
- Being visible at Paul Nicholson and Markus/DF6NM, of course ;-)
- Finally reaching the 1 A antenna current limit
- and all i have forgotten

I will record my signal of my grabber and will extract an audible signal, if possible. This will be filtered, frequency shifted to 800 Hz and published here as a mp3 file.

My grabber will show the 8970 Hz signal at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html
The 6470 Hz will be visible at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html

It is now on the Canadian and US RX stations to make possible what still seems to be inpossible: A transatlantic transmission/reception. The first time my signal can reach a 50 mW ERP limit (wind forecast announces strong wind, so a high kite angle, so a good efficiency!) on 8970 Hz. It is still not sure how the propagation behaves on this frequency at this time and locations so we may see a surprise. Of course any report is very much appreciated, no matter of what distance or country. Every clear reception above 859 km is a new world record by amateurs on VLF!

So, hope the sun will shine at good wind conds and low QRN and high interest :-)

Best 73, CU, Stefan/DK7FC

PS: Markus/DF6NM, will you be on the phone again to make QSP? :-)

More 8.97kHz operation from Germany

Just seen this post on the LF reflector from Horst DO1KHS/DI2AN :

"As you know I am planning tests on Dreamers Band from 24. July 2010 on our fieldday at Erpeler Ley, JO30ON.  I will install a 800m earth base. Possibly there is a chance for me to leave the near field. So watch out for my signal.  Beside that there is much space for near field test. So I can compare my vertical antenna with the tv transformer to the big earth base. I will be online there via UMTS so I can give you the details here in the reflector."

So, some further 8.97kHz operation from Germany next week. More details of power, mode etc expected next week but he is expecting to run 100W with QRSS600 and plain carrier.

300m long kite antenna for VLF transmission

Stefan DK7FC has now received permission from the German authorities to use a 300m long kite antenna in daylight to transmit below 9kHz. With this antenna, 200m longer than his previous one, he should be able to run up to 16mW ERP which is 10dB more than when he lasted tested on 8.97kHz. A stronger signal should allow more stations to copy his signal.

Live 8.97kHz transmission from Germany

DK7FC is transmitting now (0800-1100z) on 8.97KHz. His signals are visible on his 8.97kHz grabber . Stefan is testing further improvements to his earth electrode antenna. The message is very clearly "73" sent in DFCW 600.