First "Dreamers Band" UK test next week

As is required by my NoV, I asked the Met Office for permission to transmit in the 8.7 - 9.1kHz band next week Tuesday to Friday 0800-1800 GMT and they've confirmed it's OK.

My initial tests will be a repeat of the earth-mode tests done at 838Hz earlier in the summer using the same kit  with 4W to 20m spaced earth electrodes. I'll also test with the 70m sq wire loop antenna used for 136 and 500kHz. The most likely TX frequency will be 8.750kHz (4.480MHz xtal divided by 512). I'll find a means of getting on 8.970kHz later. Modes will be 12wpm CW and QRSS3 initially.

These local tests are not in the same league at all as DK7FC's and I'm only expecting a few kilometres at best. However, it is a start and it allows me to test TX and RX equipment and different PC packages.

6 countries on 500kHz tonight

Another good night on 500kHz WSPR with several more reports from Finland (OH1LSQ) as well as a report from Norway (LA3EQ) and several from nearer countries. ERP still in the 1-2mW region from the loop antenna.

Protecting power grids from solar storms

NASA Science News reports:

"Every hundred years or so, a solar storm comes along so potent it fills the skies of Earth with blood-red auroras, makes compass needles point in the wrong direction, and sends electric currents coursing through the planet's topsoil. The most famous such storm, the Carrington Event of 1859, actually shocked telegraph operators and set some of their offices on fire. A 2008 report by the National Academy of Sciences warns that if such a storm occurred today, we could experience widespread power blackouts with permanent damage to many key transformers."

There are plans afoot to create an early warning system to protect the US grid system in such events.

More DX reports on 500kHz

Log from early evening Oct 26th 2010 (500kHz QRPp WSPR)

This evening, the QRP 500kHz signal from the small vertical wire loop is doing well with reports again from Finland on WSPR. I still can't quite believe how a loop of thin wire with part of it sitting in the wet grass can work so well with so little power applied to it.

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.

Vertical loop versus earth electrodes antenna

Just done an interesting test comparing my vertical wire loop with an earth electrode antenna. I removed the lower part of the loop and connected the ends to ground. Matching was totally different (low Q antenna) but the performance was only 5dB down on the loop, based on reports from 2 local and one DX station. A similar test on 136kHz as the only station on in range (M0BMU 69km) was unable to copy my signal on the earth electrode antenna suggesting at least 5dB down on that band too.

Amateur VLF update: reception in 8 countries + 1310km DX!

DK7FC's summary of reports on Oct 23rd 2010

DK7FC has now summarised last weekend's test results on VLF (see table attached). His mW ERP signals from his kite antenna were received on 3 different VLF bands at distances up to an incredible 1310kms!
Stefan has certainly shown how to do it.

136kHz ERP

A fairly easy way to increase my ERP on 137.5kHz WSPR is to up the supply voltage to the IRF510 PA. Using a 20-24V supply I was able to get another 3-4dB ERP judging by the reports from M0BMU and G3WCD this morning. This evening I'll give it a go with the higher supply to see if I can get any reports from further afield. I've also thickened up the bottom part of the loop which will reduce the resistive losses by about 15%.

DK7FC's VLF tests a great success

Stefan's latest VLF kite antenna transmissions at 8.97kHz and even lower frequencies were a great success yesterday with reception as far as Eire, Italy, Poland and the UK. The attached shot shows the signal on 2 frequencies as received by Renato IK1QFK in Italy.

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.

More 500kHz 2mW ERP DX reports this evening

This evening I switched back to 500kHz from 137kHz WSPR earlier in the day. Yet again good WSPR reports from GM4SLV and OH1LSQ (1733km) who received me as early as 1716z.

8.7 to 9.1kHz NoV received

This morning I received my NoV from OFCOM to operate legally around 9kHz (see copy on RHS - click to enlarge).

Details are:

• 1yr duration
  
• 8.7kHz - 9.1kHz 
• 100mW EIRP
• Modes not specified (long periodic modes preferred by Met Office)
• Met Office have to be informed of, and approve, operating periods and be sent logs
• Home QTH or /P locations only with prior Met Office approval

No firm plans yet when I'll start local tests on this band, but within couple of weeks with QRP WSPR and QRSS. I'll put a copy of the NoV on my website in the next few hours.

Struggling on 137.5kHz

Using the same TX output power (5W) and the same loop antenna I'm finding life is VERY much harder on 137.5kHz compared with 500kHz. Last night I was being copied right across Europe on 500kHz but tonight only 2 stations (best DX 69km) are able to copy me on 137.5kHz WSPR. The reason is simple: the radiation resistance is so much lower, so losses become more significant, and the ERP is very considerably lower. There is no doubt that to increase my "sphere of influence" on 137.5kHz I'll have to make some big improvements.

New DX record on 500kHz WSPR

This evening, quite unexpectedly, I got a string of reports on 500kHz from OH1LSQ in KP03sd at an astounding distance of 1733km. To me these are amazing reports pushing my best DX on the band with just a few milliwatts ERP to new levels.  What surprises me is how well a very simple wire loop works as a TX antenna: the wire is just 1mm diameter, with a loop area of around 70m square with part of the loop on the ground buried in wet grass. I now believe almost anything is possible!

Vertical loop success on 500kHz QRP

This evening I've been WSPRing on 500kHz running about 2mW ERP from my thin vertical wire loop with an area of around 70 sq metres. The bottom of the loop just runs along the ground and at the moment is buried in the long wet grass! Despite this, my signal is being decoded in G, ON, PA and GM with best DX tonight 896km to GM4SLV up in the Shetland Is.

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.

Additional SAQ VLF transmission

From SM6NM/Lars

There will be a transmission with the Alexanderson alternator on 17,2 kHz on United Nations Day Oct 24 2010 at 11:00 UTC. Start up and tuning from about 10:30 UTC. This time we do not require any QSL-reports and will not verify. We intend to continue with our annual transmission on Christmas Eve (morning), Dec 24, at 08:00 UTC with tuning up from 07:30 UTC. D.S.

 

Holiday in South Africa - just back

No posts here for the last few weeks as my wife and I had been on holiday in South Africa. It was an amazing holiday organised by Saga and we saw some fantastic places, people and animals. Saga organise holidays for the over-50s and we were not sure what to expect, but the hotels, food, transport, and everything well exceeded expectations and the group we were with was a real mix of interesting people. The whole experience was something to feed on for years to come. For example, seeing the "Big 5" wild animals (and many more) in the Kruger National Park, seeing no less than 6 southern right whales at one spot from the shore near Cape Town and getting to within a couple of metres of wild penguins on a beach near Simonstown. Also, seeing the highlands of Lesotho where people still live a subsistence existence in huts made of dung, straw and sand without electricity and the basics we take for granted.

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.

10m WSPR DX

For a change I went onto 10m WSPR today and was rewarded with a -26dB S/N report from FR1GZ on Reunion Island (9724km away) when I was running 5W to the halo.  Interesting to note the Doppler shift on the signal (and also on the signals from FR1GZ) which suggest movement of the equatorial F layer.

Earlier in the afternoon ZD7FT was a reasonable signal on 10m SSB from St Helena and there were several VE and W's on 15m SSB.

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 reports wanted on 137kHz WSPR

Continuing to beacon close to 137.467kHz WSPR with about 20uW ERP and getting regular reports from M0BMU (69km) and occasionally others when active. I'd appreciate more reports. It would be interesting to know if others further away can see the occasional 2 minute WSPR burst, but possibly not decode it. 

137kHz receive challenges

Several people have emailed me about receiving signals on 136/137kHz. Now I'm certainly not greatly experienced in this, but a few things I've picked up from others are worth passing on:

• Many HF rigs are deaf on 136kHz, for example the FT817, although this is less deaf if you switch IPO to "on" on 136kHz. A small preamp may help as long as this is selective and doesn't increase overload and intermod from strong out-of-band stations. 
• The receiving antenna may have to be directional e.g. a small loop/preamp to allow local noise sources to be nulled. 
• DCF39 on 138.830kHz sending FSK data with a burst every 10 seconds is a good indicator of receiver performance: it should be a good strong signal in the UK. 
• Ultimately it is S/N rather than noise figure that matters on this band.
• Be prepared to use PC software such as Spectran or Argo to look for weak QRSS mode signals.

Here, I'm using the deaf FT817 (no preamp) with my 80sq m transmitting loop facing W-E at the moment and this is able to receive G8IMR's 20mW ERP WSPR beacon most of the time (188km) despite not being in the main direction of the loop. I've also copied G3XIZ, G3XDV, G3YXM and G3KEV on the band, the last being on CW. So, even a poor receiver can produce results, but it is really worth optimising the set-up (including here at G3XBM) to get more decent results. This is on the agenda.

VE7-JA QSO on 136kHz

JA7NI and Scot VE7TIL completed a trans-pacific QSO on 136kHz this morning, a first between Canada and Japan.  DX is 7162km. This was the result of many months of hard work and planning and followed several previously unsuccessful attempts.

7th new reporter on 137.5kHz WSPR

M0BMU copied my 137.5kHz QRP WSPR signal today giving me -19/-20dB S/N, which is quite a good report. Distance is 69kms. This is now the 7th unique station reporting my WSPR beacon. I'm still hoping for a report from outside of the UK soon, but suspect I'll have to increase the ERP beyond the current 20uW level to achieve this. The consistent signal report from Jim should allow me to calculate ERP based on field strength at a good distance. This will allow me to check the accuracy of my ERP measurements much nearer to home.

Sub-9kHz Amateur Radio group: 100+ members already

Since creating this new group on Saturday it already has over 100 members. Now we need to see some postings from people actually doing activity down there in the "Dreamer's Band".

See http://tech.groups.yahoo.com/group/sub9khz/

A good evening on 500kHz

This evening I was well pleased with my simple 500kHz transverter and the vertical wire loop antenna in the garden producing around 2mW ERP. The map shows stations that reported me on WSPR including LA3EQ at 769km, which is the best DX so far on the loop. The loop doesn't seem to be that directional surprisingly.

137kHz QRP transverter (provisional schematic)

Attached is a first draft of the 137kHz QRP transverter schematic. The values are not all correct or optimised on the circuit. Also the RX preamp has still to be added, but this is what I'm proposing to do. The TX is working pretty well (best DX 148km) and produces around 5W from the PA which runs cool and 20uW ERP. An updated version will appear on my website later. It may even get put in a box soon!

500kHz ERP with the vertical loop antenna

Results on 500kHz WSPR with the vertical 80sq m area loop (made from 1mm diameter wire) are very good with signal reports from G3XIZ this evening of +4dB S/N. M0BMU has given me - 4dB S/N. This leads me to believe the ERP of the system is now somewhat higher than with the short Marconi vertical. Based on earlier calculations I think my ERP, in the best direction, must be about 2mW now, some 6dB more than it was.

6th unique WSPR reporter on 137kHz

This autumn is beginning to look a bit like last year when I was taking my first tentative steps on 500kHz WSPR: each week would land me a few new reports from more distant stations. This autumn my challenge is 137kHz WSPR and so far I've been copied by 6 different stations: G6ALB, G3XIZ, G3XVL, G3WCD, G3YXM and, this evening, M0FMT. Best DX remains G3YXM at 148km. Not bad for a true QRP station with less than 5W from the PA and less than 20uW ERP with the transverter just a breadboard on the desk and the ATU sitting on the bedroom table.

Also today I copied G8IMR, Andy Talbot's QRP beacon from Southampton on 137.530kHz.

Sub-9kHz Amateur Radio (Yahoo group) formed

This new group is for anyone interested in amateur radio communications below 9kHz in the so-called "Dreamer's Band".  See http://tech.groups.yahoo.com/group/sub9khz/

VLF DX transmission with earth electrode transmission (49.6km)

DK7FC's 8.97kHz DFCW transmission received at 49.6km

Stefan DK7FC has informed me that he has successfully transmitted the message "CU" in DFCW on 8.97kHz to Michael Oexner at a distance of 49.6km. His TX puts out 250W into a 600m spaced earth electrode pair with a current into the antenna of about 0.5A. This is definitely far field reception. Stefan's earth electrode antenna is capable of further improvement, so he is expecting more successes shortly with it.

Another source of LF/MF and HF interference

This was posted on the LF reflector: we'll have yet another source of LF/MF and HF interference in the years ahead as more people install such systems. Hugh's post got immediate replies from people who'd suffered bad interference from such systems. beware of photocell panels on neighbours' roofs!

"My neighbour informs me that she is intending to have photovoltaic panels installed on her roof, in a scheme where she gets free electricity (all subsidised by the government of course!)

My concern is the possibility of high levels of interference generated by the kW inverters needed to pump electricity back into the National Grid. I would guess that such invertors probably operate kHz and might be expected to interfere with LF and VLF reception. The wiring to all the panels on the roof might act as a
very good aerial!

It also occurs to me that any lack of RF immunity to my transmissions, in the new installation, might have dramatic consequences - I know from studying electrical engineering at college that connecting a generator to the grid with incorrect phase leads to a big bang!

Has anyone any experience of such installations? Perhaps someone has one nearby and could comment on any EMC effects.

Hugh M0WYE"

More sub-9kHz experiments

Just received this from Stefan DK7FC:

Dear LF/VLF,


Today i saw the first time a flag from Norway on my VLF Grabber (http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html). I would be very fascinated if my signal would be copied in LA/SM/OH  (of course, in all countries it would be very fascinating :-) ). Are there any stations, reading the reflector, from there who have the ability to receive on 8.97 kHz (or even 6.47 kHz) with a sensitive and stable RX frequency in DFCW-600 mode?
This would be one of my wishes for this period! One. ;-)
For this weekend i planned the next VLF experiment with the 200m vertical on 8.97 kHz but the wind forecast is not too promising :-( Maybe things look better tomorrow. I have to inform the air traffic control to give out a NOTAM (http://en.wikipedia.org/wiki/NOTAM), 48 hours befor i can start...
I will announce  tmw, if i will carry out the next test, if.
The signal would be once again the strongest i've ever radiated. About 50 mW ERP is the goal.
My planned tests for this year on VLF (kite antenna):
- CW QSO to DF8ZR (16 km distance) on 9 / 137 kHz
- Copying my signal on 8970/6470 Hz in Heidelberg in CW (40.0 km, audio recording and later analysis)
- Beeing visible in DFCW-120 in UK
- Beeing visible on the grabber of Renato Romero on 8970/6470 Hz
- Becoming QRV with the 300 m vertical antenna on 8970/5170 Hz, radiating 100 mW ERP at 8970 Hz
- Beeing visible in Russia and at all interested RX stations :-)
- Maybe a TA contact?
vy 73, Stefan/DK7FC *Dreaming...*

148km on 137.5kHz WSPR!

WSPR reports on 137kHz 21.09.10

Just had a report from G3YXM who gave me -24dB S/N on 137.5kHz when I was running no more than 20uW ERP.  He is now my 5th WSPR report on the band and the best DX by far. This is so thrilling! The transverter is just sat on my desk and the PA isn't even warm.

G3YXM's screen showing my weak signal on 137.471 kHz

Possible progress on a worldwide MF allocation at WARC 2012

Info on the ARRL website suggests the USA authorities are supporting an amateur allocation at MF. See Secondary Amateur Radio Allocation at 461-469 and 471-478 kHz

 

The loop works well on 500kHz TX

Unique reports on 500kHz WSPR this evening

My vertical loop of 1mm diameter wire seems to work very well on 500khz WSPR with some excellent reports this evening, indeed some of these reports are better than I ever received (I think) on the short Marconi vertical last winter. Certainly there will be some directionality, which is the downside of this antenna. Results on 500kHz are SO much easier than on 136kHz where the lower radiation resistance and electrical size make it so much less efficient.

Loop antenna on 500kHz

My vertical loop antenna (about 80sq m area) made with 1mm diameter wire (tuned with a capacitance decade box) performs quite well on 500kHz judging by reports. Yesterday I lowered the bottom wire to run along the ground, increasing the loop area from about 70 to 80sq m.  Reports from M0LMH (223km) and M0BMU (69km) are pretty good with my 1mW ERP signal at M0BMU up to -5dB S/N on WSPR, which is as good as I've ever had and he's not in the best direction for the loop. Also, PA3EGO was up to -2dB S/N on receive. Results on 500kHz are much easier to obtain than on 137kHz although this is explainable by the much lower ERP (probably 20dB less than on 500kHz).

Increasing interest in 137kHz WSPR

WSPR LF activity lunchtime Sept 19th

In the last week there seems to have been an increase in 137kHz WSPR activity. The attached image shows the stations active on 137 and 500kHz this lunchtime.  G8IMR was the call being used by Andy G4JNT for his WSPR beacon before it died.

Why NOT to use QRO on 136kHz

Andy G4JNT was testing a 600W RF WSPR beacon on 137kHz today when he noticed burning from the plastic shed used to house the ATU. When he opened the door he saw the plastic shed and shelf melting and flames everywhere which he quickly extinguished.  LF at high power can be dangerous stuff and one reason why I've restricted my activity to QRP.