30 Sept 2011

A decent 500kHz allocation a step nearer?

From a post on the GQRP Yahoo group....

"On the IARU Region 1 website Colin Thomas, G3PSM, reports on progress in Mainz towards an Amateur Radio allocation in the vicinity of 500 kHz.

WRC12 Agenda Item 1.23 says "To consider an allocation of about 15 kHz in parts of the band 415-526.5 kHz to the amateur service on a secondary basis, taking into account the need to protect existing services;"

The CEPT Conference Preparatory Group Project Team C (CPG PT C) meeting took place in Mainz, Germany and Colin Thomas, G3PSM, reports:

At its meeting between 26 and 29 September, 2011 the CEPT project team approved a draft ECP for an 8kHz-wide band between 472 and 480kHz. This draft ECP now goes to CEPT's Conference Preparatory Group for formal ratification in November. This breakthrough, at the 11th and final meeting of the project team, occurred with the submission by the UK's Ofcom of an RSGB-drafted compromise ECP proposal supported by France and Sweden. But the prospect of an agreed CEPT position is good progress, representing a 48 country block vote going into next year's WRC-12. It needs to be noted that the draft ECP comes with significant caveats to avoid interference to the primary user, as well as the existing secondary user services. These are the maritime and aeronautical radionavigation services respectively. As secondary users we would also not be afforded any protection. It should be acknowledged that we have had support from a number of Region 1 national societies in getting to this position."

Hospitals and life's (nasty) surprises

Yesterday we had a sudden shock when my wife was rushed into Addenbrookes Hospital in Cambridge suffering from severe back pains and sickness. The day before she had been fit and well. She has been diagnosed with acute cholecystitis and is now on intravenous antibiotics and drips.

As Julian G4ILO has recently found, life has a nasty habit of suddenly throwing a spanner in the works, usually just when things are going very well. Hopefully she will make a full recovery although she has to have her gall bladder removed in the next 6-8 weeks.

....and I haven't a clue how to drive the washing machine :-)

Reverse Beacon Network - brilliant resource

A couple of times in the last few days the Reverse Beacon Network (a worldwide network of receiving stations automatically uploading spots to to the internet) has come to my aid. Today for example: a couple of CW calls on 28.060 with 5W to the halo got no audible replies, but a RBN report from PJ2T in Curacao in the Caribbean at 10dB S/N on CW proved my signal was getting a very long way.   A few days ago I found my brief call had been copied in K3 land (that's the call district and not the Elecraft factory)..

28 Sept 2011

Sputnik across the Atlantic today

The "team" today
This afternoon Andrew G6ALB, Ted G4NUA and I got together to finish building the "Sputnik" transmitter for 15m based on old Russian valves of the same type used in the first Sputnik satellite in 1957. These were given to us by AA1TJ. Andrew G6ALB did all the building work but I was the "air tester" as his CW is, he says, worse even than mine.

After a few false starts with the PSU arrangement we fired up the transmitter into Andrew's inverted-L antenna and had almost immediate success with a QSO (following our CQ) with K1GDH (Ed) near Cambridge USA who was running 5W and gave us 539.

From Andrew:
Our power out was 400mW.  PSU was nominal 24V AC @ 500 mA plug top followed by doubler for about 74V no load and 72 on load.  Grid Block keying uses -36V rail.  In all 3 diodes, 3 caps, 3 bleed Rs.  Very simple, fairly safe also. Filament supply is 5V DC plugtop [stabilised] and 18R resistor which gets warm!
A second Sputnik rig is being built now and all being well we will be on the air on Oct 4th (Sputnik Day) to try for some more QSOs.

27 Sept 2011

Disappointing day on 10m today

Most of today 10m was relatively quiet here with just inter-G WSPR reports. I was about to switch things off when I noted a report from CX2ABP (11127km) just appeared. Maybe tomorrow conditions will be better.



26 Sept 2011

10m - AMAZING propagation again today

Starting with reports of my QRP WSPR signal from VK6BN at 0640z, the day on 10m has been simply amazing. The band has been WIDE open to all continents today and sounded (almost) as good as I ever remember it. Several USA stations worked (with 59 reports) on QRP SSB. One report on WSPR from VK4 suggested just 50mW would have been enough to get me reports from Australia!

I just hope this upsurge in conditions lasts a while. Just maybe, the peak of cycle 24 could yet be a good one. An indication of conditions is how far above 28.5MHz stations spread out. Stations were spreading out to at least 28.6MHz on SSB and this is a weekday with no contests.

25 Sept 2011

10m WIDE open - best for me in MANY years

Having just got back from France I switched on the FT817 on 10m to find the band wide open. Not that much on SSB (W4, 5B4 etc) but on WSPR with just 5W to my halo I was getting reports right away from the southern USA (-12dB S/N from W4DJW at 6537km and KB9AMG at 6300km). K9AN was giving me reports of +5dB S/N suggesting 5mW would be enough to cross the pond. Sounds like this autumn conditions are going to be excellent in 10m and possibly 6m.

UPDATE at 1845z: band still open to the USA, S.America and Europe. Just like the "good old days"!

19 Sept 2011

Earth Mode VLF article in October RadCom

If things go to plan, there should be a 3 page article of mine in the October RadCom. As I am away in France I've no idea if this appeared or not.

IC7000, FT450D or KX3?

After many years I am thinking of upgrading my "main" HF/6m rig and these are my main options. Any views on which one to go for? I shall only use the rig for QRP mainly but a bit more power could be useful at times. VHF and UHF could be a nice addition with the IC7000 but the FT450D has better reviews. Of course the KX3 is some months away from production, especially in a CE approved European version. Ideally I'd like an FT817 successor, but this doesn't look likely before I die.

18 Sept 2011

France

Enjoying a few days in the Perigord region of France with excellent scenery, history, food and wine. Rural France remains very unspoilt and beautiful. No ham gear with me at all though - too busy relaxing.

11 Sept 2011

Nuclear Fusion - our energy needs met soon?

Nuclear fusion plant of the future
Are we getting close, at last, to making clean nuclear fusion, as opposed to dirty nuclear fission currently used in power generation, a reality? The BBC reports that the UK has joined a project with a US laser lab to work on the creation of powerful lasers to compress atomic nuclei to the point fusion occurs. See http://www.bbc.co.uk/news/science-environment-14842720. If this breakthrough can be achieved commercially it could radically change the outlook for the world. Growing energy costs prohibit widespread creation of water desalination plants, desert irrigation, electric cars and the like, but think what would be possible if energy costs became inexpensive and plentiful for ever. Global warming is only too real, but I have faith that with strong investment and push we will make nuclear fusion a reality in the next 30 years. This could well save the planet. The main dangers on the way are the vested interests of the US petrochemical companies who will do everything possible to bias US government policy in their favour, denying vital fusion research the funding it needs.

8 Sept 2011

Success on 137kHz QRPp

 My 137kHz 0.2mW ERP signal by M0BMU at 69km
Today has seen some very encouraging results achieved on 137kHz with the QRSS30 0.2mW ERP beacon. Firstly copy from G4AYT in Whitstable Kent at 118km (in the null of my TX loop antenna) and excellent reception by M0BMU using his ferrite rod antenna at 69km - see screen shot. Several more stations are looking out for the signal which will remain on overnight.

LF kit improvements

24W 137kHz QRSS30 beacon TX (ERP 0.2mW)
137.5kHz 24W transverter (for WSPR) 0.2mW ERP

Today I completed the first stage of my ERP improvement programme on 137kHz completing the rebuild of the QRSS30 beacon and the transverter used for WSPR on the band. Photos attached show both of these. My ERP has now increased to around 0.2mW with both rigs. The output from the PA stage in both rigs is around 23-24W. More power will be easily possible by raising the PA supply voltage later.

7 Sept 2011

Sputnik valve TX tests

This afternoon G6ALB and I got together to build a 2 valve 21MHz transmitter using a couple of Russian valves of the same types used in the original Sputnik 1 satellite in 1957. Surprisingly I've never built a valve transmitter before. Even today, Andrew did most of the building. My input was to wind a toroid and to help sort out the wire ends of the two valves. The valves were kindly supplied by Mike AA1TJ.  The breadboarded TX is shown in the picture. On a test this evening over the 3km path between our QTHs the 400mW TX was copied fine on my IC703 and 10m halo antenna.  Even at the lowest HT voltage (around 30V) his signal was still solid copy on the "Sputnik". Our aim is to have a pair of these units ready for Sputnik Day (Oct 4th) and to work each other and other more distant stations who are using similar rigs.  See also http://aa1tj.blogspot.com/2011/07/sputnik-qso-party-transmitter-prototype.html

6 Sept 2011

Higher power on 137kHz

Today I did some work on increasing the output power of my 137kHz transverter used for WSPR, with mixed results. When driving the IRF540 PA with a decent square wave I can get around 24W out (was around 5-8W) from a 13.8V supply with decent efficiency. When using the drive from the mixed-down transverted signal I am having less success. The issue is driving the MOSFET gate from a really low impedance and ensuring it is as square as possible with the right mark-space ratio. Most 137kHz transmitters do this by driving at 274kHz with ICs designed to drive a pair of MOSFETs whereas I want to go in at 137kHz using discrete parts. This is a solvable challenge and I'll have this up and running in a few weeks. 25-30W would give me 6-8dB ERP improvement and more should be possible from a higher PA supply voltage. This would take my ERP up to around 0.5mW  ....heck that's high power for me!

5 Sept 2011

More QRPp testing on 137.7682kHz

My QRSS30 137.7682kHz beacon is on until 0800z Tuesday morning sending XBM in QRSS30 with the full call at 10wpm periodically for full ID.  Reports (including no copy) would be much appreciated.  I'm hoping to improve on the recent best DX a few days ago - a report from G3WCB at 101km who got the signal pretty well at times despite the 140uW ERP.

4 Sept 2011

CW training on the internet

If, like me, your morse code could be improved then you may like to go to http://lcwo.net/main and see the array of training material available there. It is probably the best place on the internet where you can brush up your skills.

Sunspots

At the moment we seem to be seeing quite impressive sunspot numbers, at last. See http://www.solen.info/solar/ . This bodes well for this coming autumn and winter which should see 10m well open to the USA on a regular basis by October. Such conditions offer the chance of transatlantic AM QSOs between 29-29.1MHz even with quite low power. In previous sunspot maximums it has been possible to work AM DX with just a few watts to a mag-mount on the car. AM makes a change from SSB.

Boy's Book of Crystal Sets

One of my favourite books when I first got interested in radio back in the 1960s was the Babani series book number 126 entitled The Boy's Book of Crystal Sets. The link takes you to a PDF copy of this book. I was fascinated by the shortwave version shown in the book and remember building a variety of it using parts I had. It was such fun copying distant DX stations with something so simple. Years later I managed to copy Radio Havana, All India Radio and even (directly from Australia) Radio Australia on a simple crystal set. All good simple fun showing the magic of radio. There are several websites on the internet today dealing with the design of sophisticated crystal sets capable of quite exceptional preformance.

1 Sept 2011

Improved QRSS30 beacon on 137.769kHz

This afternoon I did some experimenting with some new 42mm 3C90 toroids and my 1kV WIMA polypropylene capacitors. I've managed to increase the RF output of my QRSS3/30 beacon by around 5-6dB so I've put this on beaconing over the evening and overnight period in the hope that someone will see the signal and send me some screen shots. ERP with this new beacon is around 150uW.  Previous tests with the beacon ERP at around 50uW showed that the signal could be detected in The Netherlands. Each dB gained should improve my chances of being seen ever further. The screenshot shows my signal as received 101km away by G3WCB - quite a good signal at the peak of fades.

31 Aug 2011

What is my ERP currently on 137kHz WSPR?

Based on some measurements and calculations using the improved ATU (see photo) today, this is my calculation:

Measured antenna current in the TX loop = 2.13A
Area enclosed by the loop = 80 sq m
P = (I^2 x A^2)/(205 x 10^6) at 137kHz   (see p101 of "LF Today" book available from RSGB)
where P = ERP,  I = current in amps and A = loop area in sq m

P = (2.13 x 2.13 x 80 x 80)/(205 x 10^6) = 141uW

This is not a lot (but more than ever before) and this is before I start on the "ERP improvement" programme.


137/500kHz ERP improvements

Today I made a start on improving my ERP on 137kHz and 500kHz.

Firstly, I've bought a pile of Wima 1000V polypropylene capacitors from Farnell. With these I have now made a new ATU to match my TX loop (breadboard only ATU so far) which will allow me to run some 6-10dB more power into the loop without the ATU components overheating and failing. My old switched capacitor array was an old school capacitance decade box and this was marginal with tuning changing as caps heated up!

Secondly, I am going to change the MOSFET PA design to increase the 137kHz power from around 7W RF to about 30W. This should be worth around 6-8dB. I plan to do something similar on 500kHz too.

Finally, I've got some more wire to allow me to double the thickness of my TX loop. This will be done later and will be worth 2-3dB as long as I alter the 3C90 ATU (step down) matching transformer.

In all, these changes will give me up to 10-13dB more ERP and, with some luck will allow me to get more reports on QRSS and WSPR. It will take some weeks to implement these, but by late October my range should improve on both bands.

30 Aug 2011

VLF NoVs to be extended

OFCOM has confirmed that the UK NoVs to operate in the 8.7-9.1kHz VLF band will be extended later this year if holders request this.  Discussions with the Met Office have confirmed no problems have been observed with operation in this band. This is good news. Currently there are, I believe, 4 VLF NoV holders in the UK: G3XIZ, G3XBM, G4WGT and G7NKS.

WSPR database issues

Some people in the UK, including me, have been unable to find wsprnet.org today. After working perfectly overnight the site just disappeared and via Virgin Media and just some other ISPs it isn't available currently. For others it works OK. This isn't the same as the recent overload issues: something has changed at their end or in the way the site connects to the internet. Hopefully all will be resolved soon or I'll have to resort to CW more often!

A useful site to check connections is http://www.downforeveryoneorjustme.com/# which allows you to check if a site has really disappeared or not. According to this, wsprnet.org is still there, so I assume it is a routing issue.

Shortly before the link was lost I was getting VK8AW well on 10m WSPR. Guess I'll have to wait now to see if my 5W WSPR signals made it to Australia this morning.....

UPDATE: 1415BST - it's back.

29 Aug 2011

US politicians and science - are their politician brain dead?

As the USA starts its next election campaign I'm seriously worried that the country is likely to end up being run by a brain dead, ignorant and downright dangerous politician from the fundamentalist, anti-global warming, anti-science, isolationist brigade. See this article from the New York Times kindly sent to me by Michael AA1TJ.  Although this is about republicans, there are as many democrats with equally stupid views. It seems you have to be stupid in all things (apart from making money) to make the grade over there.  Seriously, we are talking about the nation that is supposed to show the world a moral lead, to champion policies to safeguard the planet.

American citizens, please use your head when selecting you future politicians as it matters very much.

10 unique reports on 500kHz

Stations copying me on 500kHz WSPR
Last evening's WSPR outing on 500kHz was very successful considering this is August. 10 different stations managed to receive and decode my 1mW ERP signal with best DX report from EI0CF at 602km. Best seen here was GM4SLV in Shetland at 896km. This just using a thin wire vertical loop (80 sq m area) around the garden with the lowest side running along the fence in the foliage!

28 Aug 2011

Back on 500kHz WSPR

This afternoon John GM4SLV informed me he was restarting tests on 500kHz WSPR from way up in the Shetland Islands with about 150mW ERP.  So, I've fired up my own 500kHz WSPR system in the hope of copying him later this evening. So far I have had spots of my own 1mW ERP signal from several stations with best DX so far being PA3ABK at 306km, but nothing seen (yet) from John. I'm hoping a few more stations will appear too.

26 Aug 2011

http://goo.gl/

Just discovered Google also do a "shorten your URL" feature too. Go to http://goo.gl/ to try it out. I knew about tinyurl but only just noticed the Google equivalent. As with other shortened URLs, some security systems may recommend avoiding such links.


25 Aug 2011

Bitsbox - an excellent UK component supplier

Just a couple of days ago I placed an order with Bitsbox, a UK component supplier for a variety of components needed in my upcoming VLF/LF experiments. Today, by first class post, the order arrived. Bitsbox charge a fixed £1.50 first class post charge which is very reasonable. The service and value for money are truly excellent. Their website is www.bitsbox.co.uk  and they stock a wide range of useful parts.  If you've not used them before, and I had not, I can highly recommend them.

24 Aug 2011

Heathkit kits again?

The Southgate amateur news page carries a story that Heathkit may be about to start the production of kits again after a break of many years. This would be excellent news. Heathkit used to produce world class kits that were in a class of their own with first class instructions. Let us hope they decide to restart amateur radio kits as well in due course. In the amateur radio field Elecraft are the nearest.

23 Aug 2011

500kHz

With the autumn season not too far off I am turning my thoughts to 500kHz and 136kHz again. This weekend I hope to return to 500kHz WSPR as GM4SLV is testing his new 500kHz antenna and ATU. After that it will be my turn to improve the ERP on 136kHz with a new PA, ATU and antenna.

21 Aug 2011

Antenna folklore

From the LF-reflector and very true.
Antenna engineers use to say about design goal limits of antennas:

    Small
    Efficient
    Wideband

Pick any two (meaning you can't have all three...).

73   Clemens   DL4RAJ

Inter-G 10m DX with 5W WSPR

In the last 24 hours, as well as some excellent long distance DX, I've been surprised by the 10m reports from stations within the UK. For example G4CUI in IO93 and G6BHS in IO81, both around 170km. These are not one-offs as exchanges with G4CUI are common at almost any time. I must keep a record of all the QTH locator squares I get reports from on 10m and 6m WSPR from within the UK. WSPR is an excellent mode for "sniffing out" openings.

20 Aug 2011

Chile on 10m WSPR

Just exchanged WSPR reports with XQ6FOD in Chile at 12285km on 10m this evening at 2054z. At first I thought this was a bogus report but checking on QRZ.com the call is genuine. I think this was Es linking into some TEP F2 propagation as I was getting good reports from Spain.

Good Es DX on 10m

This afternoon I put my WSPR beacon on 10m for a while and was surprised how wide open the band was. Strong Es signals from across Europe and N.Africa plus a couple of excellent reports from R9SA in LO71 square at 3661km to the east. I'm wondering if the band will open up across the Atlantic today. Even with 500mW I was getting very good reports. Reports from OY1OF suggest even 500uW would be enough for a report.

14 Aug 2011

Best results yet on 8.76kHz earth mode

8.76kHz earth mode signal in 45mHz BW at 6km
This morning I slightly changed my VLF low input impedance tuned preamp by increasing the tuned circuit Q and gain of the first stage by around 6dB. After lunch I did a test at 6km from home to see what effect this had on the S/N of my 5W beacon. In a 45mHz bandwidth (previously 11mHz) I was getting a signal around 18dB S/N using Spectrum Lab on my 80cm square loop on the ground. With an earth electrode antenna the signal was marginally weaker and the noise level higher.

My signal is the steady carrier (with a 2min ID break) at 8.7605kHz. The large wobbly line is interference, but who or what is the signal at 8.754kHz? This is rock steady and appears to key on and off every 5 minutes. It looks like some sort of control signal, or is someone else near Cambridge testing?



13 Aug 2011

Rural Suffolk - England at its best

We are blessed with a wonderful variety of scenery and plenty of still quiet rural countryside to enjoy despite our cities being crowded. This afternoon my wife and I enjoyed a ride through rural Suffolk in East Anglia where we stopped at a number of delightful small churches.  There is a lot to be grateful for in an English summer with a gentle breeze, warm sunshine and the sound of swallows, woodpeckers and bees overhead.

Wispy WSPRs

Overnight I was looking for MS propagated WSPR signals on 10m. There were a few early morning decodes as well as plenty of evidence of MS bursts which were too short and too Doppler shifted to permit successful WSPR decoding.

12 Aug 2011

Perseid meteor shower

Overnight tonight the Perseid meteor shower will peak with some dazzling displays in the early hours of Saturday morning if the sky is clear. With luck, MS conditions will be good on 10m, 6m, 4m and 2m with some long bursts. Not sure what band(s) to monitor but may see what can be heard/seen on JT6m on 6m.

11 Aug 2011

Inside a QRPer's brain

G3XBM's brain!
Today I had my brain scanned for scientific research. For several years I've volunteered as a guinea pig at the Centre for Speech, Language and the Brain at Cambridge University.  It involves doing the occasional language test and about once a year having an fMRI scan whilst doing some task involving language. The university has its own MRI unit for medical research. The whole MRI thing is painless and is actually rather relaxing, especially when they are doing a full scan and the machine is vibrating which is like having a massage. If anything untoward is seen in the scans they inform your doctor, which is good. Let's hope that it looks OK. Certainly it looks much like the one I had done a few years ago.

The purpose of the research is to better understand how the brain functions and they hope this will help with people recovering from strokes.  It must be so rewarding to be working in this field either as a PhD student or as a post-doc researcher.