Over 100km on 137kHz with 50uW ERP

Just got a screen grab from G3WCB 101km away showing my QRSS30 beacon signal being received at his QTH near Windsor. Mine is the lower trace in which you can see "BM" (part of XBM). It is not strong, but there. I will leave the beacon running with around 50uW ERP during today.

A few hours later G3WCB got me stronger with the XBM very clear on the screen.

Henny van Elst in Holland was also seeing traces at the right frequency, but too weak to positively identify.

QRSS3 beaconing on 137.6748kHz

My QRSS30 (slow CW) LF beacon has just been started up. I'm hoping that QRSS30 will get me reports from a bit further afield.  Any reports and screen grabs would be much appreciated. It will be on for much of the weekend unless I need the antenna for some VLF tests. The message cycle takes about 25 minutes and best results will be with Argo, Spectran or Spectrum Lab software on a PC and FFT bandwidths of around 0.1Hz.

Message:     XBM in QRSS30, pause, then G3XBM in 10wpm
Freq:           137.6748kHz
ERP:           50uW (antenna 80sq m vertical loop)
Location:    JO02dg, Burwell Cambs

2 transistor transceiver kit

The Four State QRP Group is offering the new "HamCan" transceiver kit for sale at just $30.  It is a 2 transistor crystal-controlled CW transceiver, delivering 0.5-1W TX power with enough sensitivity and selectivity to receive plenty of signals. They claim it is a minimalist yet good performance transceiver. The kit features a high quality PCB, low parts count and fast and easy building. It is claimed to be an excellent kit for first time builders. It has been selected as one of the ARRL Midwest Convention's Buildathon kits. 

More information at http://www.wa0itp.com/hamcan.html .

Mains hum powered beacon

Recent tests with earth electrodes at VLF have got me wondering about a simple QRSS HF/VHF beacon TX powered entirely from the rectified mains hum and other crud coming from a couple of earth rods in the ground.  Not sure of the available power, but I suspect it would be in the 0.1 to 2uW region, maybe more. This may be enough to drive a low voltage QRSS beacon for example. You can buy power harvester ICs these days for this purpose, but with a step-up mains transformer there may be a volt or two available at a few tens of uA and that alone may be enough to drive a keyed oscillator. The ultimate in free power beaconing!

3km DX on 8.97kHz WSPR today

This morning I successfully decoded a VLF earth mode WSPR signal from G6ALB at a distance of 3km. Signal was quite strong, but for some reason the WSPR software refused to decode it (apart from once) despite clocks being reset at each end. This is my best WSPR DX reception on VLF so far. Andrew was running 40W to an earth electrode antenna. I was copying him on an earth electrode antenna although the WSPR signal was stronger later on the 80m square vertical loop in the garden.

In the afternoon I used my wife's laptop and WSPR decoded every time at -16/-17dB S/N, a very decent signal. There is a video showing the VLF WSPR set-up if you want to see it. 

G3XBM is off to Mars

NASA is collecting names to be put on a microchip that'll be on the Mars Science Laboratory rover heading to Mars in autumn 2011. The rover has special CW indentations on its wheels spelling out  JPL (Jet Propulsion Laboratory).

To add your name/callsign go to http://marsparticipate.jpl.nasa.gov/msl/participate/sendyourname/

Bicycle portable in Blackpool

David G4AKC has been on his bike and working some excellent DX (like VK/ZL) on SSB and CW on 20m from his bike parked up next to the seaside in Blackpool. He uses and Alinco DX-70 on battery power with a  home made top loaded 3.5m long vertical against a tuned frame, and operating "over the sea water".  He says several QSOs were possible at the 1W level. See http://www.qrz.com/db/g4akc .

28MHz WSPR DX

Just a couple of outings on 10m WSPR this week, but some excellent reports from 5 continents using 5W and the small halo antenna. Interesting to see what must be Doppler shift drift on both the Reunion Is and Australian reports, presumably because of moving F-layer over the equator?

28MHz getting too easy?

For the first time in several weeks I put my WSPR beacon on 10m this morning. Without any effort, the 5W and the halo got reports from the Middle East and Australia. With the solar flux regularly above 100 now, I'm finding that 10m has moved into its "easy" phase when worldwide DX is becoming easy.  Also, with the Es season just days away now, the European activity will be plentiful and WSPR reports from Europe with microwatts certainly probable.

Solar activity heats up

There is a nice article on the NASA site about the recent upsurge in activity in solar cycle 24. See http://science.nasa.gov/science-news/science-at-nasa/2011/14apr_thewatchedpot/ . No-one has, to my knowledge, changed their views that this cycle will be a low peaked one. However, every solar cycle seems to be different and we can live in hope for a while yet.

Earth mode VLF test at 1.095kHz

When testing with utilities assisted earth mode in recent months I seemed to be getting weaker signals at 8.76kHz compared with my tests at 0.838kHz last summer. So, today I decided to go back and recheck results at a lower frequency at test sites 1.6, 2.6, 4.5 and 5.1km away from the 5W QRSS3 transmitter at home. Test locations were rural fenland roadsides, a National Trust car park and 2 roads in the next villages.

I used the same TX as at 8.76kHz, but divided down by a further x8 to 1.095kHz using the 4060 divider. The receiver was a horizontally orientated 30turn, 80cm across, series tuned loop into a low impedance MPF102 FET preamp with a drain circuit peaked at around 1.1kHz and emitter follower into PC running Spectran.

My initial test at 1.6km was a total failure - no signal visible at all in Spectran at 0.73Hz bandwidth. Then I realised that I had BOTH the garden earth electrodes in use at the TX (neither connected to pipes). A phone call to my wife and one wire was connected to the pipework in the house with the other still connected to the earth electrode at the bottom of the garden some 20m from the house. The signal then appeared at good strength.

Signals were received at all test locations indicated, but there was no signal visible (in QRSS3 bandwidths at least) when moving away from the roads into nearby fields or at some other test locations where pipes were absent (or plastic). At one location I rested the loop within 2m of one of the fenland water courses, but nothing was detected. The image attached  is the signal at 4.5km, which is strong in 0.79Hz bandwidth. Even stronger signals are possible with more optimum positioning, but I keep having to move my loop to avoid it being crushed by oncoming farm tractors! I do get some odd looks too.

My conclusions from the tests to day are:

• This was definitely utilities assisted earth mode. The initial (accidental) test today with 2 earth electrodes not connected to water pipes failed.
• Signals are strong close to where the metal pipes are, but rapidly disappear where no (metal) pipes are close by.
• Signals at 1.095kHz are definitely stronger than at 8.76kHz in the 3-5km range.

There is one more test to do at some point that needs some assistance locally (I think within 10km to work). I want to try a long stable carrier test with someone looking in the very narrow bandwidths we've been using for the radiated tests recently. What I'm wondering is just how far from the pipes does an earth mode signal "leak"? Using Spectrum Lab with the very weak signal bandwidths like 0.4-2mHz, the weak remnants of a signal might just be visible some way from the "easy" utilities assisted coverage area.

The remaining tests I want to do still with earth mode are:

• River bank or sea coast test - just how far can one get?
• True earth mode in open country without any utilities assistance
• Earth mode at higher frequency e.g. around 70kHz, which I can manage with my present set-up. Based on recent OFCOM correspondence I believe such tests would be legal as long as there is no intentional radiated signal or interference to others.

This class of experiment is not in the same league as those being done by the radiating VLF DXers, but fun nonetheless, especially as anyone can do this sort of test without NoV or special permits needed.

111km optical QSO in Yorkshire

G8AGN/P and G0EWN/P achieved a 111km speech QSO on optical communications using 0.5W red LEDs and Fresnel lenses on April 6th 2011. Brilliant stuff.

Heathkit from 50 years ago

Dave G3UUR pointed me in the direction of the 1961 American Heathkit catalogue in which I found the EW19 electronic workshop kit. My memory had this as the EW1, but I must have got this wrong. My mum and dad bought me this for Christmas 1961 and it was this that got me started in radio as a hobby.  The Medium Wave radio was used for my first DXing late in the evenings. Also, the simple MW transmitter (using the crystal earpiece as a mic) got me across the house - my first transmissions.

SAQ 17.2kHz this week

There will be an extra transmission with the Alexanderson alternator station SAQ on 17.2 kHz on Thursday April 14th 2011 at 12:45 UTC with tuning up some time before.   The transmission is directed to "The 5th European Conference on Antennas and Propagation" in Rome, Italy. There will be no QSL verification of this transmission.

An odd ladybird in a London park

During a picnic in London's Springfield Park today, a very strange ladybird (family name Coccinellidae) came to join us. I've seen red ladybirds with black spots and vice versa, but never a yellow one with white spots! Anyone know what sort it is?

Bell System Techical Journal now online

The complete Bell System Technical Journal from 1922-1983 is available on line and searchable. See
http://www.alcatel-lucent.com/bstj/ .

G3XIZ testing on VLF overnight tonight

Chris G3XIZ will be active on VLF again this evening and overnight on 8.9766616kHz although the start time is not yet known. My VLF on-line grabber is already on in readiness, as is the grabber at G3ZJO. Chris has recently been improving the match to his VLF loading coil and antenna and is working on a new variometer.

Optical Comms DX

The latest RSGB news reports that G8CYW and G8KPD have set up a new UK record for optical DX over a distance of just under 90km in NE England using SSB and FM with a design that appeared in a recent RadCom.

10m WSPR

10m WSPR reports (5W to a halo)

Another good morning on 28MHz (10m) today with WSPR reports from 4 different Australian stations plus RA9 and G's by tropo (I assume at 250km).  I was also copying VQ9JD on WSPR.

Transequatorial 70MHz QSO

SV2DCD and ZS6WAB have had the first ever 70MHz transequatorial (TEP) QSO on 70 MHz. It has also been announced that Namibia now has access to the band. Watch the video.

Earth mode VLF tests with E-field probe RX on car

As an experiment today I rigged up an E-field probe on the car to try to do something similar to LA3EQ's earth mode tests of the last few days. Instead of WSPR I used QRSS3 on 8.76kHz putting my usual 5W into the earth electrodes (one connection to the copper pipe ground and one at the bottom of the garden 20m away). The E-field probe consisted of my 1.5m long whip into an MPF102 source follower feeding a 2N3904 emitter follower with roughly the same arrangement as the PA0RDT E-field probe. The probe was attached at the top of a 2m long PVC pipe poking out of the rear window vertically. The actual E-field probe was powered by an internal 9V battery and was mounted about 1m above the car roof.

With the laptop PC running Spectran on the front passenger seat I was able to drive around and glance at the screen whilst moving. In the village there was a reasonable copy of the signal but outside of the village I only managed to get a couple of places 1km apart where the signal was strong enough to copy. One was at 2km and another at 2.1km. Compared with a loop on the ground at the same spots last year the signal was at least 10-20dB weaker. Although I am getting reasonable copy of the 11905Hz Alpha beacon the signal level is around 10dB down on the level on the 80m sq loop at home. So, maybe the E-field probe can be improved still.

In summary, with utilities assisted earth mode, for that is what the propagation is, the car mounted E-field probe is, as yet, nothing like as effective as a loop for RX.

I'd like to rig up some way of driving along with a horizontal loop attached to the rear of the car about 0.5m above the ground. This way I could drive around the local area and log where copy is possible. Presently I have to get out of the car with the loop to take a measurement when doing earth mode tests.

So, a useful test even though the results were not outstanding, or even good :-)

WSPR at VLF

Seeing Jan LA3EQ's recent 4km earth mode tests with WSPR at VLF I must pass on something I'd forgotten about.

WSPR software is able to transmit a WSPR signal at least to 22kHz just by selecting the TX frequency to the chosen frequency. For example, if you want to send WSPR at 8.970kHz just select the band as "other", set the dial frequency to 0.000kHz and set TX frequency to 0.00897kHz. Listening to the tone it definitely is at the frequency stated.

What I haven't determined yet is how high the WSPR software will decode at. When I tried WSPR some time ago on 8.97kHz I used my up-converter and FT817 as the receiver. When I tried to decode directly at 8.97kHz today (setting the RX PC's dial frequency to 7.470kHz) it did not decode.

Bank bonuses - direct action Dutch style

Being really VERY annoyed with the size of totally unjustified bank bonuses in the UK, I was amused to read this article which proves that peaceful and non-violent "people power" can work. No need to spray paint on banks (pointless and unhelpful), just threaten, en mass to withdraw your money.

http://www.guardian.co.uk/business/2011/mar/27/dutch-bankers-bonuses-axed-by-people-power

A 100W PA for VLF use

BK Electronics in the UK make a range of MOSFET PA units with built-in toroidal power supplies. They have a 100W unit for £53, which is very reasonable for a built and tested unit. I believe these units work to 137kHz with a small modification and they would be ideal for 8.97kHz VLF use. There are versions up to 1kW, but these are quite expensive.

See http://www.bkelec.com/Modules/Amplifiers.htm

Easy mistakes

On Monday night I was looking for Uwe DJ8WX again on 8.97022kHz.  To my great surprise I copied nothing when G3ZJO and M0BMU were getting good copy. I'd copied Uwe several times before. After suspecting my PC sound card was faulty, I found out why I copied nothing tonight: on Sunday I'd retuned my loop ATU to copy M0BMU on 500kHz and I'd forgotten to retune it back to 8.97kHz. Although Spectrum Lab locked onto GBZ OK, the sensitivity was about 20dB down! We learn by our mistakes.

G3XIZ a good signal on 8.976662kHz VLF today

Chris G3XIZ has just started TXing again and is a decent signal here in 424uHz bandwidth with the signal up to 20dB over the noise (see picture). Eddie G3ZJO was also getting a good signal. At 1530z Chris dropped the power 10dB but unfortunatley I was unable to copy at this QRP level, whereas G3ZJO was still able to.

Back from holiday

There have been no posts this last week as I have been away on holiday in Devon in SW England staying at my brother's cottage. For once the weather was excellent with wall-to-wall sunshine every day. I did not take any radio gear with me this time but plan to take the FT817 when I go next time to do some pedestrian portable cliff-top QRP DXing. Last May I worked some excellent European DX on 6m with just the FT817 handheld.

Loop TX antennas at VLF

At first sight the idea of a 10m x 10m wire loop as a TX antenna at 8.97kHz VLF sounds a non-starter as a way of radiating any useful power. Having tossed the idea around with others though it appears that, although very inefficient, it would not be that much worse than a smallish Marconi vertical because these antennas need very large (and lossy) loading coils, height and good grounds to be effective. With 100W to such a small loop around 0.45uW could be radiated. Already G3XIZ has spanned 218km with just 2uW to his vertical, so for small gardens the VLF TX loop is worth a look.

G3XIZ and DJ8WX on 8.97kHz

The Spectrum Lab plot showing reception here again of these two stations around 8.97kHz VLF. Both were using back garden antennas. DJ8WX is around 645km away. G3XIZ about 45km.

GPS cannot always be relied upon

As if to remind us of the vulnerability of modern technology yet again:

The MoD has informed OFCOM of the following GPS jamming exercise

Dates: 19 – 26 May 2011.

Times: limited periods between 0700z 19 May to 100z 2 May 2011. 

Location:  The ground based radar jamming events will take place in the SW approaches against the remote radar head at Portreath 21-22 May, undertaken by F-18 Growler aircraft. Additionally there will be radar jamming against deployed targets in South West Wales throughout the period 19-26 May. Communications and airborne radar jamming will take place throughout the same period on the East Coast with aircraft operating within the North Sea Military Danger Areas. Communications and maritime unit radar jamming will take place in the SW approaches and Bristol Channel. Falcon aircraft will operate from Sea Level to FL240 unless jamming AEW aircraft where they may operate above FL245.

Note: Safety of life operations will take precedence over exercise activities at all times.

Emergency radio kit

The terrible Japanese earthquake, tsunami and nuclear crisis has reminded us all that modern 1st world technology cannot always be relied upon. The UK Foreign Office and the BBC have webpages suggesting essential items as an emergency "grab bag" to have ready in such circumstances. One of the attractions of simple QRP gear is its ability to work when nothing else may, for example using a small battery or solar cells with a compact CW rig that can be taken anywhere with a throw-out HF antenna. In the event of a sudden and unexpected disaster, would you and I be able to communicate still?

8.97kHz very sensitive spectrogram online

Paul Nicholson in Todmorden, Yorkshire UK has put on line his steerable and highly sensitive spectrogram for the VLF Dreamer's Band around 8.97kHz. Paul's system is super sensitive and detects just about anything going. His new spectrogram can be "steered" to a specific direction and the display clicked to show exact frequency and S/N levels. There is also a roll back function so that records from a few hours to days back can also be checked. Marvellous! See http://abelian.org/vlf/fbins.shtml

Great care needed when IDing VLF stations

A word of caution to those of us looking for very weak signals around 8-9kHz. DJ8WX was copied here overnight on 8.970022kHz without any doubt and my grabber was clearly able to see his close-down around 0700 today. The frequency and the trace timing corresponded perfectly. Likewise with G3XIZ and DK7FC/P some weeks ago.

This evening I was looking very carefully again at the Spectrum Lab screen from the last 24 hours in 424uHz BW and readjusting audio gain ranges, screen colour saturation and contrast. Out of the noise appeared another very very faint line, not at 8.970022 but at 8.96998kHz. I've attached the screen shot here (I have overlaid it with the time for clarity).

My immediate reaction was this must be Ossi OE5ODL as this is the frequency he uses. Then I checked his grabber and saw he was not operational overnight last night! So, what looked like a trace on his frequency cannot be him. It must instead be some artefact of SL or something else. We have to be very careful when seeing traces at very specific VLF frequencies: it may be an indication of a given VLF amateur station, but without some modulation or turning on/off of the carrier a doubt remains.

Sadly I don't think I did see Ossi today after all, but I shall keep looking.

New Sub-9kHz Amateur Radio website

For some time I've wanted to tidy up the pages on my website that dealt with the various aspects of VLF amateur radio below 9kHz. So, today I've launched a new site entitled Sub 9kHz Amateur Radio bringing together my information more accessibly. The original pages just grew and grew as activity at VLF just took off. It is almost 1 year to the day since DK7FC made his first historic DX on 8.97kHz. Since then we've come a VERY long way!

The new site has a table showing the VLF DX records. This is not fully populated or correct yet, so I need everyone's help to get this up to date in the next couple of days please. If you are aware of errors or omissions please let me know right away.

Another addition - to be much expanded - is a page on TX stations and their equipment. Please let me have photos, schematics of antennas, transmitters, loading coils etc.  Another page deals with the kit needed to receive on the Dreamer's Band. It is easy stuff that can be built by anyone. Also a page linking the various software packages available freely. Yet another page lists the VLF grabbers (incomplete still - tell me of others!) which are such a vital resource. 

Also included on the page is more data on earth mode (through the ground) communication which is a very accessible way of starting out on VLF as much of the kit is re-usable for experiments with radiated VLF tests (same loops, probes and pre-amps can be used).

Please let me have constructive feedback so I can make this as good as possible. I hope you enjoy the site.

The end fed halfwave antenna (EFHW)

Steve G0KYA has a nice pdf document he's created describing how to make simple end fed half wave antennas (EFHQ). These band specific antennas can be very effective and simple when mounted either vertically or horizontally. They can be made with PVC covered wire, fishing poles or aluminium rod. See http://www.infotechcomms.net/downloads/Endfed_halfwave_dipoles.pdf.  Many years ago we experimented with these on VHF handhelds and achieved results some 6dB better than with a standard 1/4 wave whip, but on 2m they were on the long side! On HF they are capable of low angle radiation good for DX.

4m QRP success - 229km today in the contest

Using my small 1W QRP 4m transverter recently built into my loft dipole I've just managed a QSO with G4RFR 229km away in Dorset (IO90AS) using CW in the RSGB Cumulative contest. He was on SSB and it was hard work, but in the end a full exchange was made.  Also heard G3EDD, G4ASR, G3BCU, G3TCT, G4DEZ, G1EHF on the band on SSB and G4ZTR on CW.

DJ8WX copied again on VLF (645km)

Uwe DJ8WX is currently transmitting a long dash on 8.90022kHz and his signal was copied well on my VLF grabber overnight in a 424uHz bandwidth. Also visible is a mystery signal around 8.9701kHz that most people think is some sort of local noise source but it is very repeatable every night.

Monitoring 8.976607kHz for G3XIZ

Just back from a few days with our grandson and family and the PC is on looking for the latest VLF test from G3XIZ. Whilst I've been away I hear that OK2BVG has been received in the UK too on VLF. Activity on the Dreamer's Band (8-9khz VLF) is going from strength to strength with new stations getting active on RX and TX almost daily now in Europe.

10m WSPR - reports from Australia today

WSPR reports 10.3.11 morning

This morning my 5W WSPR signal on 28MHz reached Australia with reports from VK5ZK and VK6DZ. Best DX is 16275km, a new WSPR record for me on the band. In the last 3 months I've had WSPR reports from 6 continents. Not bad with 5W to a small wire halo antenna at this stage of the sunspot cycle. At 1100z I'd been received by no less than 4 different Australian stations plus Israel, the Faroes and UK.

DJ8WX on 8.970022kHz again

Just weak a very weak trace overnight (you have to look hard!) from DJ8WX on VLF. Compared with his signals a few days ago he is at least 10dB weaker. Not sure why as nothing has been changed here. G3ZJO also copied Uwe weaker than before, although Eddie was getting him slightly better than me using his E-field probe antenna. By the way, this small trace (in blue/white) covers a period of 8 hours and is looking for the signal in an incredibly narrow 424uHz (yes you read it correctly - microhertz) bandwidth.