Volcanic ash and propagation

My son, his wife and 1 year old son are currently stuck in Los Angeles: all came down with a virus and were unable to travel back to the UK after a 2 week holiday. Not that they could have flown anyway, because all the planes were cancelled as a result of the Icelandic volanic ash. They are now stuck there until May 1st, the next available flight, and that is assuming the volcanic ash is not an issue then.

An upside of the flight ban are the beautifully clear blue skies in the UK completely devoid of vapour trails for days now. Not sure what effect, if any, this has on VHF/UHF tropo or even sporadic-E conditions.

DX birds: swallows have arrived

This morning I saw that the first swallows of the spring had arrived in our village. The swallows fly from Southern Africa all the way to Europe every spring arriving between late March and the end of April. Many nest in the same nest for years and years. The returning swallows, house martins and swifts remind me that this magical journey has been done for thousands of years and that we humans are just one small part of the Earth's diversity.

New 80m AM transceiver kit from Small Wonder Labs

Dave Benson K1SWL has produced a QRP 80m AM rig with a crystal controlled TX and 50kHz tunable receiver. Full details at http://smallwonderlabs.com/Retro-75.htm including a PDF builders guide. There is also a Yahoo Group at: http://groups.yahoo.com/group/SWLRetro75/

VLF amateur DX in Poland (290kms) on 9.6kHz

Marcin SQ2BXI has sent me this message today (April 17th 2010):

In last night we have VLF eksperiment in 9,6kHz in SP2KDS Club.Club signal copied Jacek SQ5BPF -distance 290km.
Movie tranmiter: http://www.youtube.com/watch?v=2sn6AmpkwlU&feature=player_embedded
and Polish page: http://www.sp2kds.pl/136khz/298-pierwsze-proby-nadajnika-w-pamie-marzycieli.html

Next experiments will soon have to 8.970kHz...
73! Marcin SQ2BXI

Next 8.97kHz German test delayed 2 weeks

Stefan DK7FC says it will be a couple of weeks before his next VLF test transmission on 8.97kHz. This gives me more time to get the RX ready.

Icelandic fireworks - lots more to come?

Volcanic activity on Iceland appears to be getting worse with more activity recently. Disruption to air flights in the N.Atlantic may become more common. See this article in New Scientist.

Ham and other books on eBay - still time to grab a bargain

My ham and other books including some magazines about the remote island of Tristan da Cunha (ZD9) selling on eBay still have a few days to run, so you still have time to get a bargain. Check out http://myworld.ebay.co.uk/rlapthorn

Even greater DX on 8.97kHz?

Stefan DK7FC has now got his 600W 8.97kHz VLF PA working and is waiting for a windy day to get his kite supported antenna up in the air. With a few dBs more power and more well-equipped stations listening/watching on 8.97kHz (33kms band) Stefan is hoping that >1000kms can be spanned in the next test transmission.

Rockmite 20m kit (unbuilt)

For some time now I've had an unbuilt Rockmite 20m QRP transceiver kit waiting to be put together. The problem is I have so many other things on the go that a 20m QRP kit is way down the list and 20m was never my favorite band: I'd wanted a 40m kit but they only had 20m ones in stock when I bought it over a year ago. The kit has never been opened and I'm thinking about putting it on eBay. The current price for the kit in Europe is 45 euros plus shipping.

What would be a fair price?

Free power transmitters

Mike AA1TJ has sent me an interesting letter about using thermoelectric modules to generate a few milliwatts of power from body heat. This got me thinking about the other ways of "harvesting" free energy from vibration, movement, heat, mains hum fog, RF from radio stations etc. One bizarre idea from a few years back was a leg-brace that powered a mobile phone by leg movement (see left). There are ICs coming onto the market that scavenge energy from various sources allowing low powered devices to be powered for free. The challenge for us QRPers is to think of creative new ways to generate a few milliwatts to get signals across oceans. Who will be the first to work DX using RF rectified "off-air" from the local FM radio or TV transmitter?

Talk request from Peterborough CLub

Having given a talk about "kitchen sink" simple radio last year, the good folks at Peterborough have kindly invited me back to talk about sub-9kHz radio. Date confirmed as Wednesday Aug 25th 2010.

Some ham books of mine on eBay

Today I've put a few of my books for sale on eBay. They include RSGB and ARRL handbooks. If you are interested do take a look. If you live in the Cambridge area and want to pick them up locally then there will be no postage to pay. See http://myworld.ebay.co.uk/rlapthorn

Thoughts on VLF Earth-Mode and Induction DX

Earth-mode (through the ground conduction) and induction communication (mutually coupled coils) have an inverse cubed attenuation with distance. Think about this: I reached 0.3km with earth mode for an audible CW signal with around 4W RF and a simple 5m base receiver and 10m base transmitter. To double this range, all other things being equal, means increasing power by 18dB to 250W. To double range again means raising the power to kWs. Conversely, improving the detectable sensitivity threshold by 18dB (increasing the electrode spacings at each end, using WSPR or QRSS, etc) reduces in power needed for a given range dramatically: my 4W signal could be detected at 0.6kms or a just a 63mW signal could be detected by earth mode at 0.3km. In reality, especially in urban areas, water pipes and cabling may help "propagation" and achievable ranges may be greater. DX is relative, especially with conduction and induction at VLF.

Still being heard on 500kHz

This evening the reports on 500kHz WSPR have been quite reasonable, despite the smaller antenna than a few months ago. Three unique reports from PA and from the UK so far this evening.

Blog visitor DXCC

Just noticed that this blog has been visited by people from 102 different countries this year so far.

Another new WSPR report on 500kHz

Last night I got another new 500kHz WSPR report, this time from PA0O in the north of the Netherlands at 440kms. This brings the total of unique WSPR reports on the band (via the internet database) to 83 stations plus a couple of others who reported by email. Overall the total number of unique reports on 500kHz including CW is 86 stations in 11 countries. Not bad for 1mW ERP. The most recent reports have been with my "degraded" antenna consisting of the 5m feeder to my 28MHz halo as a top capacity hat.

W1VLF's page about 8.97kHz experiments

Paul W1VLF is getting operational on the 33kms band (8.97kHz) and has already been received 5kms away running 50W into a base loaded vertical. He has created a website to detail the progress as he goes along. At the moment the website only has details of his HUGE loading coil. See http://rescueelectronics.com/9-Kilohertz.html .

82nd unique 500kHz WSPR report

This evening I got a new unique WSPR report, the first in 3 weeks, from Chris G3XIZ. This is my 82nd on the band. Chris has just started on WSPR and is likely to come on WSPR TX shortly. He is a very experienced 500kHz CW operator.

Auroral Chorus Recording (Paul Nicholson)

If you missed the streamed natural VLF auroral chorus emissions the other morning here is a nice recording made by Paul Nicholson in Todmorden UK.  It is a truly unbelievable sound, produced not by birds but by the auroral electromagnetic activity at VLF.

Moonbounce from Aricibo

The Arecibo Observatory Amateur Radio Club KP4AOwill be putting the 1000-foot radio telescope on the air for 432 MHz EME from April 16-18. It can be heard with a small hand-held yagi pointed at the moon. A 15 dBi antenna and 100 W will be enough to work us on CW.

Times of operation are:

April 16: 1645 - 1930 UTC,
April 17: 1740 - 2020 UTC,
April 18: 1840 - 2125 UTC

Tx Frequency: 432.045 MHz,
Rx Frequency: 432.050 to 432.060+
Tx power: 400 W,
Antenna gain: 60 dBi

Antenna feeders

Today I have to move my two main antenna feeders which wind their way untidily through the house from the back of the house, where they enter the building, to my shack in a front bedroom. This means getting up into the small loft space to run the cables across and down. Some years ago I had a bent end fed antenna on 10m squeezed up there and it managed to get to South America on QRP SSB. A small ground plane for 10m (with a capacity top hat to shorten the vertical section) would probably perform quite effectively.

UPDATE: Job done. It took about 1 hour and everything is fine.

VLF Chorus audible in UK this morning

Auroral Chorus, a natural VLF emission that sounds like birdsong is audible in the UK this (early) morning. It is still audible at 0650z. Check out the VLF natural radio receiver at http://abelian.org/vlf/test.html as soon as possible, as it will soon be gone.

Operating on 40m

This evening, as my wife was busy watching the TV, I decided to go onto 40m SSB with 10W pep and see what was about, not chasing DX. I worked a special event station OZ2SPACE  and a couple of other stations in Europe. Actually I must confess that this sort of rag-chew operating rather bores me these days: I'd far rather be building something or experimenting with WSPR. Working DX with QRP is fine on the other hand.

G3XBM's 500kHz article in May's Practical Wireless

The follow-up article on my 500kHz transverter and WSPR experiments appeared in the May edition of Practical Wireless today. I hope it encourages a few others to give 500kHz a go, especially as my approach is a simple and easy one.

DF6NM and DK7FC active on 8.97kHz today

Not one, but 2 stations were active on 8.97kHz today in DFCW mode. Part of DK7FC's transmission was copied at 902kms away in Warsaw and DF6NM, running a much smaller station and antenna, was copied 21kms away. A first QSO on the 33kms band cannot be too far away now!

4th Amateur VLF test transmission on 8.97kHz this weekend

Stefan DK7FC is planning to transmit again on 8.97 kHz VLF if the wind is able to support his kite antenna. The tests start Saturday April 3rd, at around 1000 UTC. The mode used will be DFCW-600 (dual frequency very slow CW). Several stations across Europe will be listening some using tiny E-field probe antennas.

Temporarily QRT - shack becomes grandson's bedroom!

It had to happen sooner or later: our elder grandson, now 2.5yrs old, is staying with us a couple of times in the next few weeks as his mum and dad pack to move flat. Tonight he moved from the usual travel cot to a real bed for the first time .....in my radio shack. So, I shall be unable to operate evenings for a while so no 500kHz WSPR I'm afraid. Daytime operation may be possible, but apart from 10m WSPR I doubt I'll be able to do any serious operating. In the meantime he is fast asleep and looking very cosy.

500kHz WSPR - fewer stations around now

500kHz WSPR has gone rather quiet of late with fewer stations on most evenings. So far only M0BMU has reported me tonight, despite my report being pretty strong. A new 500kHz WSPR receiving station this evening is OY6FRA and it would be great if he could hear me 1164kms to the north. This would not be a new DX record but it would be another new country. The OY6FRA club station's antennas are shown on the left.

Sunspots on track

Latest graphs (March 2 2010) from the NOAA space weather site suggest that the smoothed sunspot number predictions are on track with a maximum of 90 forecast to occur in May 2013. This is not a high number but would still suggest excellent conditions on 15,12 and 10m from later this year until 2015. If you have not experienced 10m when wide, wide open then you are in for a nice surprise: dust off your QRP rig, put up a 16 foot long dipole and work the entire world!  Better HF conditions are already here and they will only get better still as the year progresses.

10m is calling me

As I sat winding my ATU for 500kHz this evening my thoughts were again turning to 28MHz. Although I've plenty of ways of getting on the 10m band already, I've always fancied a simple homebrew rig either for CW or sideband.  One idea is to make a QRPp WSPR beacon that I could leave running almost continuously. I've a 14.060kHz crystal that might just make it to 28.124600 when doubled in the right circuit. Into a simple phasing SSB circuit and I could have a few milliwatts of 10m WSPR.

Change to 500kHz ATU

This evening, as an experiment, I rewound the tapped coil on on ferrite rod based table-top ATU for 500kHz using 0.56mm enamelled wire rather than 0.2mm. The antenna current was up by (at most) 20%,  but on-air it made no difference with reports on 500kHz from M0BMU being the same as before. Before I put away my 500kHz kit for the summer I may try an L vertical with a 15m long horizontal top as I have access to a nice tree in my neighbour's garden which would provide a convenient support for the far end.

A new personal WSPR DX record

This evening I put the WSPR beacon first on 20m and then 30m running 1W into the 5m long vertical matched with the Elecraft T1 auto-ATU. First came a report from a VE6 in Alberta on 20m then a new DX record on 30m with a report from VK2/VK6DI at 16969kms. Not bad going for 1W to an indifferent antenna. Some of the European reports suggest that I'd still have been heard in Europe with just 5mW. VK6DI is a QRSS and weak signal mode enthusiast: see his site at http://www.users.on.net/~davroz/vk6di/

Receiver for 8.97kHz DX experiments

Jim M0BMU successfully copied signals from DK7FC on 8.97kHz VLF last weekend using a small loop antenna and preamp feeding into a Spectrum Lab soundcard VLF receiver. I've put a copy of Jim's latest preamp on my 9kHz page on my website. Others have tried voltage probe antennas.

Talk Invites

Sharing the real fun of ham radio is important to me and so I enjoy giving the occasional talk to clubs on subjects such as QRP, simple radio fun, WSPR and the like. The Chelmsford ARS has asked me to do one on 500kHz and WSPR in November. Not liking night driving, I'm hoping someone there will offer me a bed for the night.

Litter in the UK

Some parts of the UK appear to have a problem with litter on the roadside verges. In our area this is only collected once every 6 months, so bad areas can look awful after a few months. There are several initiatives to help co-ordinate local "self-help" groups where volunteers go out in groups to tidy up particularly bad patches. See http://www.thebigtidyup.org/default.aspx . I'm hoping to get involved in East Cambridgeshire where I'm sure a few of us can make a difference.

More amateur VLF DX on 8.97kHz

Since I was last at home there have been further tests from DK7FC on 8.97kHz. His signal has been received in Germany, Netherlands, Italy and the UK at better strengths than a week earlier as he managed to get the ERP up a bit more. These experiments are truly ground breaking with amateur signals being successfully received by ionospheric propagation on VLF. See http://abelian.org/vlf/9k/ for some reports from the UK station who received these signals. Jim Moritz M0BMU also received the signals last weekend using a small loop antenna at a portable location near Tring.

Back from (rainy) Devon

Got back from our week in Devon today. Although I packed my VX2 dual band mini portable it only got used to listen to BBC Radio 4 I'm afraid. All week, apart from a couple of brief breaks it rained and rained. There is an old saying, "come to sunny Devon where it rains six days out of seven". As much as I love the county where I, and my ancestors back to at least the 1400s lived, sadly the saying is true! Get good weather and there's nowhere else to beat it. Get a wet week and it's a bit bleak. This is a picture of Bolt Tail in better weather last Sunday.

QRP 2m FM

For the next few days I'm going to stay with my brother in S.Devon. I'll be taking along little ham gear, just the VX2 handportable to see what I can work out /P on the cliff tops. Usually I find activity levels down there very quiet but occasionally I manage to surprise myself by working some simplex DX. The weather forecast is normal for when I go to Devon - rain, then rain and then some more rain :-(  The VX2 is a rather good little 2m/70cms portable - very small and light - but it works better with a decent antenna such as a 1/4 wave whip on 2m, which also works pretty well as a 3/4 wave on 70cms too.

Sub-9kHz NoV application being processed

Rod Wilkinson confirmed that he's received my application today at OFCOM:

Hi Roger,

Many thanks for your email and you will be pleased to know that your application has arrived on my desk this morning, I am sure all will be in order.

As mentioned earlier my colleagues have contacted the Met Office but we are awaiting their response, I am afraid this may not be a prompt process.

I will keep you updated as we progress but if you do wish to check on the status please do contact me.

Vy 73

Rod

A WSPR first on 8.97kHz

This afternoon I set up my "earth-mode" station using a pair of electrodes about 10m apart in the garden, one near the house and one at the bottom of the garden. Using my 4W audio amp driven from the WSPR software in the PC I transmitted a WSPR signal on 8.97kHz. With a separate PC at the other side of the house and with 1m of wire as the "antenna" plugged into the mic socket of the PC I went listening for my WSPR signal.  Sure enough, there was my earth-mode transmitted signal at -15dB S/N. Distance was only about 10m but at least the TX, WSPR system and ground electrodes work, so I now can go out into the fields behind my house to look for my WSPR beacon using a decent, sensitive 8.97kHz RX next time. Strictly I need my sub-9kHz NoV to do this test, but as nothing is radiated I doubt anyone will care.

As far as I know this is the lowest frequency on which WSPR has ever been successfully used.