300% more efficient wind turbine?

Japanese professor Yuji Ohya and his team have investgated the design of wind turbines and suggested a honeycomb-like structure could triple the amount of wind energy that can be produced by offshore turbines. See Tech Future site for more information.

Perseids meteor shower tonight

The Perseids meteor shower is supposed to be a strong one peaking this evening. I may run the WSPR software overnight on 10m to see if any bursts are long enough to support a 2 minute WSPR transmission.

LATER: Overnight I copied PA0PSY at 0044z by what looked like MS: quite strong signal, seen once only, with Doppler, over a 300km path, although it could also have been aircraft reflection. Unfortunately I didn't see the WSPR screen to examine the actual screen trace.

Sunspots - high 60s

Have you noticed how high the sunspot count is climbing? Today it is 66 or 70 depending on which measure you take. This is not far off the sunspot count predicted at the peak of cycle 24 in about 3 years' time. If this trend continues, we could be in for a bigger peak than some were predicting. It could by just a blip.

10m halo re-erected

Today I rebuilt my Homebase10 10m wire halo and put it back up on the pole. I was going to erect a spiral top hat vertical for LF but decided instead to go HF. VSWR was good from 28-29MHz and WSPR reports from G4IKZ (18km west) good with just 1W out. I can use this antenna, with feeder strapped, as a vertical on 500kHz. For 136kHz I've decided to erect a wire loop rather than a Marconi and will support this from the 10m antenna mast.

417km on 500kHz QRP ....with just earth electrode antenna!

Just been received in Holland by PA0A on 500kHz WSPR when using just the 20m spaced earth electrodes! The ERP is around 250uW and I am amazed that this non-antenna is able to work so well. I've also been emailed by Victor PA3FNY to say he also copied me at -27dB S/N.

500kHz WSPR with 20m spaced earth electrode antenna

The effectiveness of the 20m spaced earth electrode "antenna" (virtually nothing is in the air) continues to amaze me. Last night I copied PA0O on 500kHz WSPR and this morning I've got 4 reports of my sub-1mW ERP signal from M0BMU around -19dB S/N at a distance of 69km. This level suggests the (non) antenna is only around 6-8dB down on my best top loaded  short vertical used to get reports from OK2BVG 1232kms away last winter and the ERP is around 200-250uW.

160m WSPR receive with earth electrodes

Although I've not matched the 20m spaced earth electrodes yet on 160m, it makes a fine RX antenna. See the logs on WSPR in just the last hour.

500kHz WSPR

This afternoon I restarted 500kHz WSPR transmissions using about 250uW ERP from the earth electrode "antenna" in the ground. Two reports received from M0BMU at 69km received so far (-24/-25dB S/N). In the next few days I'm hoping to erect a vertical top loaded Marconi antenna to use on both 136 and 500kHz, so it will be interesting to see how reports compare with those obtained on the earth electrode antenna.

500kHz with the Elecraft K3

On the Elecraft website I see there is an article showing how to use the K3 transceiver on 500kHz. The K3 will receive on 500kHz but needs an external PA (described) to get around 25W output. See http://www.elecraft.com/TechNotes/k3qtx_v2_pa3cw.pdf

FT818 - a "what if" radio that does not exist....

The FT818 handheld:

• All mode, all bands 1.8-1296MHz with 5MHz and 70MHz
• 5W RF (2W 1296MHz)
• 3.5AHr Li-Ion battery pack (2hr charging)
• Built in random wire and whip auto-ATU
• Full colour OLED display
• Multi-function DSP noise reduction
• RF Speech processor

.....wouldn't that be nice for Christmas 2010? Sadly, it doesn't exist except in our dreams.

US and Canadian East Coast Loran closed today

Apparently the very last Loran TX on the east coast of the USA and Canada closed at 0500 today. This will make reception on 136kHz much easier in this part of the world. At one time Loran was one of the most popular navigation systems in the world but now made obsolete by GPS units costing a few dollars and fitting in your pocket.

14.9km on 136kHz QRP (earth electrode antenna)

This morning I did some more tests using my little 136.93kHz 2W QRSS3 beacon feeding into the 20m spaced earth electrodes. The TX end was unchanged, but this time on receive I used my 30t 80cm loop resonated with about 700pF and fed straight into the high impedance input of my E-field probe. Results were as follows:

• At 2.4km good copy by ear (12wpm CW would have been very solid)
• At 8.6km good copy using Spectran
• At 14.9km clear copy of my callsign and locator in QRSS3 with Spectran on the Gog Megog Hills near Cambridge (see screenshot)

All these locations are more or less in the line of the earth electrodes that run NE-SW from the home QTH (JO02dg).  Another RX test some 11km to the south of the QTH  resulted in no visible trace, suggesting the TX earth electrodes are behaving as a loop antenna with some directionality. This was not the case when the same earth electrodes were used at 0.838kHz some weeks ago and when the mode was mainly conduction through buried utilities. Remember, this is ultra simple stuff:

• 2W out crystal controlled QRP 136kHz beacon TX on a 5 x 5cm board (see picture)
• Invisible ground "antenna" that can't be seen, even when a few metres away from it.
• No attempt to match the TX to the earth electrodes.
  
• Simple loop + FET impedance matching circuit and deaf FT817 at the receiver end.

It would be interesting to work out what the ERP must be and interesting to speculate what would happen with such a system at 73kHz. Pity there is no allocation there today.

DK7FC's 6th VLF kite TX experiment

Stefan DK7FC is testing his 600W VLF transmitter into a 200m high kite supported vertical today (Aug 1st). He expects to radiate about 10dB more than in his last test (on 8.97kHz) and may transmit at a slightly lower frequency today (around 6.5kHz) depending on where the antenna is best matched. You can check progress on his grabber at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html .  Results from his last tests were amazing with reception across Europe in DFCW600 mode (dual frequency slow CW). For a summary of the reports (screen grabs) see http://abelian.org/vlf/ss100321/.  To copy his signal you will need a decent low noise/high dynamic range receiver (E-field probe or loop with preamp and filters) at VLF feeding into a PC running a package like Spectrum Lab, Argo or Spectran using narrow 3...5 mHz FFT settings and about 1 minute per pixel running speed. You also need to know precisely where to look, so calibration will be very important.

136kHz QRP QRSS3 beacon video

This is a video showing the 2W QRP beacon for QRSS3 on 136.93kHz. Using a 20m spaced earth electrode transmit "antenna" it has been copied 8.6km away using an E-field probe antenna.

2696km on 10GHz - new record

A new DX record for terrestrial (non EME) communication has been set with a QSO between D44 and CT on July 10th over an incredible 2696km. See http://www.hyperatlantica.ch/ for more information.

136kHz with QRP and earth electrode antenna

Today I increased the power from my QRSS3 136.93kHz beacon to 2W out of the PA into the 20m spaced earth electrodes. Another "ride about" test locally with the deaf FT817 and E-field probe RX antenna gave the following results:

At 2.4km good copy on the Spectran display

At 4.6km clear copy on the Spectran display.

At 8.6km the signal was detectable, but weak (see picture attached from Spectran screen).

These reports are roughly "end on" to the electrodes and I've yet to try other directions such as orthogonal to them. No attempt was made to match the PA output to the impedance presented by the earth electrodes which are around 40-60 ohms below 10kHz; I've not measured it at 136kHz yet.

Even with true QRP it looks like a range of at least 10km should be possible on QRSS3 (and probably WSPR) with a half decent receiver (better than my crude set-up) using just a 20m earth electrode TX antenna on 136kHz.  I'll leave the QRSS3 beacon running over the weekend on 136.93kHz from my QTH in Burwell, Cambs (JO02dg) and any reports and screen shots would be much appreciated.

Class E MOSFET PA for 136kHz

I'm trying to optimise an IRF510 MOSFET PA for use in the 136kHz beacon and later transverter design. Alan Melia G3NYK has a very useful page on practical approaches to class E designs for 136kHz at his page http://www.alan.melia.btinternet.co.uk/classepa.htm together with a useful Excel worksheet to come up with practical values for the output network. Class E using square wave drive on the input can produce very good efficiencies, thereby reducing heatsink requirements.

136kHz PA progress

Today I started to modify my 136kHz QRP beacon to increase the power from 250mW to around 5W using an IRF510 MOSFET PA. I've still work to do to optimise the design but hope to complete this tomorrow.

More on time travel

A rather long, but fascinating article on the possibilities and issues with time travel is on Wikipedia.

Quantum time machine?

Researchers at MIT may have come up with a way of travelling through time (and space) using quantum closed timeline curves or CTCs. It has always fascinated me that in quantum mechanics one can describe things as wave functions that have existed in all space and all time, past present and future. It takes a leap of imagination to consider the possibilities. For an explanation see http://www.telegraph.co.uk/science/7904712/Quantum-time-machine-allows-paradox-free-time-travel.html

This is the abstract of the original MIT paper:

"This paper discusses the quantum mechanics of closed timelike curves (CTC) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based on post-selected teleportation (P-CTCs). We compare the theory of P-CTCs to previously proposed quantum theories of time travel: the theory is physically inequivalent to Deutsch's theory of CTCs, but it is consistent with path-integral approaches (which are the best suited for analyzing quantum field theory in curved spacetime). We derive the dynamical equations that a chronology-respecting system interacting with a CTC will experience. We discuss the possibility of time travel in the absence of general relativistic closed timelike curves, and investigate the implications of P-CTCs for enhancing the power of computation."

Simple ??? See http://arxiv.org/abs/1007.2615

136khz transverter

I'm getting ideas, and parts, together to allow me to build a small transverter for 136kHz. For the TX low pass filter I'll use either T68-2 or T157-2 (or something on between) toroids as these seem most suitable at up to 30W.  For the RX input tuned circuit I still need to find a suitable inductor, preferably tunable. Any ideas?

Further 136kHz earth electrode tests

Later today I hope to do some more tests on 136kHz using 250mW QRP to the earth electrode "antenna". Last night I went out to look for the QRSS3 signal locally but realised the battery in my E-field probe was flat, so heard and saw nothing!  I expect to see the signal to well beyond 5km.

UPDATE: Well a repeat of the test on July 19th gave less encouraging results. Reasonable copy on QRSS3 at 1.5km but no copy visible at the same spot 4.6km away from the QTH (within 20m). Not sure what has changed as the earth electrodes are the same. Maybe the soil is slightly more damp?

PW author Gordon King G4VFV now silent key

Practical Wireless author Gordon King G4VFV died yesterday from stomach cancer. Gordon wrote many radio and TV related books and contributed regularly to PW. He lived in Brixham, Devon.

Parts from Farnell - good service

For the first time I ordered parts from Farnell on-line yesterday. In the order were some 3C90 toroids (16mm and 42mm) to use in my 136kHz transverter.  I cannot fault the service: parts were here the next morning with free delivery. Just remember the prices on the internet are shown less VAT. For on-line orders there is no minimum order quantity.

4.6kms with earth electrode "antenna" and 250mW on 136kHz

Today I tried some more experiments with my 20m spaced earth electrode "antenna" and small QRP beacon TX on 136kHz. I switched over to QRSS3 and  used the FT817, E-field probe and PC with Spectran to see where copy stopped. 1.5km from home and solid copy on QRSS3 when holding the E-field probe box as high as possible above the car roof. Then I drove on to a spot 4.6km from home and copy was again achieved, albeit not as strongly.  I'm certainly getting a signal radiated beyond the near field.  I'd like to check "antenna" directionality by looking for signal levels with the QRSS3 beacon at all compass points some 4-5kms away from the QTH.

In the meantime, if anyone near Burwell, Cambs wants to look for the QRSS3 signal near 136.93kHz I'll leave it running until about 8pm tonight when I have to switch off as my grandson is sleeping in the shack bedroom. Any reports would be amazing.

Simple 136kHz beacon TX

Francis F6HSI very kindly sent me a "divide by 26" module based on a small micro-controller. With this I've built a small beacon transmitter for 136kHz (QRSS3 or 10wpm CW) by dividing down from 3560kHz, the QRP calling frequency on 80m. At the moment it only puts out 250mW and, with the earth electrode "antenna" used, the ERP probably considerably below 1uW.


Using my 20m spaced earth electrode "antenna" on TX and with a PA0RDT designed active antenna with a 19 inch whip antenna feeding into the (deaf) FT817 I could copy the 10wpm CW at 0.4km across the fields.

New VLF DX record today: 5.6km on 838Hz earth mode

Today I resumed my VLF earth mode tests using 4W into 20m spaced earth electrodes. The aim of the test today was to determine the absolute maximum range possible by utilities assisted earth mode. Best result was 5.6km along Commissioner's Fen to the west of Burwell. Signals were just copied at this distance using the 80cm 30 turn loop and preamp into the PC running Spectran. A test a 6km resulted in no detectable signal.

An amateur solar plane "satellite"?

Recently, Qinetic managed to keep a solar power plane aloft for 7 days using its onboard navigation to keep it over a fixed location and using solar cells to top up batteries to keep it flying at night. Could such solar powered flying devices could be used as "satellites" flying a few miles above the earth to support amateur VHF/UHF repeaters and experiments i.e. a more sophisticated version of balloon experiments?  See http://www.bbc.co.uk/news/science-environment-10664362 .

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.

70MHz, Icom and Yaesu

There are now approaching 40 DXCC countries granting access to the 70MHz (4m) band and further countries are granting access every few months it appears. See  http://www.70mhz.org/bands.htm.  I do hope that some of the commercial "big boys" such as Yaesu and Icom start to make VHF multimode rigs that include 4m in future. It can't be too difficult to add this band. Apart from the latest ChineseWouxun FM handportables (see  www.wouxun.co.uk) and ex-PMR units, only the FT847 has 70MHz coverage. Imagine how operation on 4m SSB/CW would take off if Yaesu's FT817 successor has 4m coverage as well.

Technology Page

The Tech the Future page has an interesting mix of articles on new technology and is worth a read from time to time. See http://www.techthefuture.com/

6m northern Es opening

Just took a look on 6m this evening and heard several northern beacons (GB3RMK, GB3LER, OY6BEC) and worked GM8IEM in IO78 square way up on the north of Scotland followed by GM4DZX in IO88 on CW.  Nothing else about, but this sort of opening to more northern areas is common at this time in the Es season.

Fabulous noctilucent cloud image

Check out this image of a noctilucent cloud formation. See http://www.spaceweather.com/swpod2010/10jul10/CROISIER-Alexandre1.jpg

Soundcard based VLF receiver

SM6LKM has a very neat sound card based VLF receiver ideal for listening to sub-9kHz ham signals and SAQ on 17.2kHz. On his website you can download the files and instructions.

Noctilucent Cloud storm

Recent nights have been good for these high altitude night-time visible mesospheric clouds which return strong microwave echoes, so should be good for 10GHz super-DX. See www.spaceweather.com

NOCTILUCENT STORM: Last night, sky watchers in Europe witnessed the finest display of noctilucent clouds (NLCs) so far this year. Electric-blue tendrils spread as far south as France:"I could see the NLCs from my window," says photographer Alexandre Croisier of Brittany, France. "So I rushed down to the beach to take this picture--a 6 second exposure with my Canon 350D.  

In England, the same display stretched from horizon to horizon. "There was quite a lot of detail visible, including swirls and tiger stripes," reports Mark Jones of Leamington Spa, UK. Even city lights did not overwhelm the NLCs. "I had no trouble seeing them from southwest London," says onlooker Maurice Gavin.

July is often the best month of the year to see these mysterious clouds. High-latitude sky watchers should be alert for electric blue in the nights ahead.

iPhone electronics toolbox app

http://www.iphone.roskosch.de/electronictoolbox.php has a useful app for the iPhone (and Touch?) which allows you to carry out lots of useful electronics calculations.

Tour de France - live action

On our way through Burgundy today we got diverted because of a roadblock at St Fargeau which turned out to be because the Tour de France was coming through. We were able to watch the whole "circus" coming through over about 2 hours and took some great pictures and video clips from about 10m from the  racing cycles. I'd no idea that, before the riders came through, there are loads of vehicles throwing goodies to the waiting crowds. I managed to catch a Frisbee that my grandson will have when he next comes to stay. Great fun and an opportunity to be part of the real French experience, purely by chance.

French food

Being in France currently it gives me a chance to try some good, and inexpensive food. This evening we've enjoyed a first class 4 course meal with wine that was superb. Carpaccio (marinated raw beef with a pear sorbet - tastes wonderful) followed by Loire fish, cheeses, and a delicious sorbet and tart and good coffee to follow. Tomorrow there are a few more chateau visits. I can recommend Logis de France as good value places to stay and eat.

Miracle Whip Yahoo group

Many years ago now I started a Yahoo group for people interested in the Miracle Whip and similar antennas. Amazingly the group now has over 1200 members.  Opinions vary about the effectiveness of the MW - in my opinion it is a compromise antenna that is inferior to many simple whip antennas - but it is easy to tune and with a counterpoise or reasonable ground does allow DX contacts on all modes when conditions are decent. See http://groups.yahoo.com/group/miraclewhip/ .

French wedding

These last few days we've been enjoying our son's wedding in Brittany, France where the weather, company, food and wine have been great. Unlike an English wedding, this one has taken 3 days to get through! Great fun though with a day dedicated to eating crepes (pancakes) yesterday followed by a siesta in a meadow under the oak trees!