29 Jun 2010

Solar flux levels

We're now months into cycle 24, yet the solar flux levels are showing little signs of rising much: they're still in the mid 70s only and the sunspot count is below 20. Recent predictions have suggested it's going to be a very weak cycle and events so far confirm this. However, the sun throws surprises and in 6 months time the picture may be better. We can only hope. See http://www.solen.info/solar/

300m long kite antenna for VLF transmission

Stefan DK7FC has now received permission from the German authorities to use a 300m long kite antenna in daylight to transmit below 9kHz. With this antenna, 200m longer than his previous one, he should be able to run up to 16mW ERP which is 10dB more than when he lasted tested on 8.97kHz. A stronger signal should allow more stations to copy his signal.

28 Jun 2010

GQRP Limerick Sudden kit

The GQRP club (subs £6 per year - excellent value) is now selling the Limerick Sudden kit. This is an improved version of the classic Sudden direct conversion receiver for various single HF bands. The cost includes everything you need including battery , knobs and case. See http://www.gqrp.com/sales.htm. Members Price - only £34.00 (Non members £40)

27 Jun 2010

Supporting MS research by skydiving

A young friend of ours, Josie, has multiple sclerosis (MS) very badly and it has devastated her life in many ways. Undaunted, yesterday Josie did a skydive to raise money for the MS Society charity. So far she has raised over £1500. She is so plucky. If you care to give something please visit http://www.justgiving.com/Jo-Hardiman. Two others in our family have had MS, one of whom died a few years ago. It really is a most awful condition that robs, mainly young people, of their hope and future. Josie's uncle was Len G4IRZ.

Not quite QRP - the Haiku Omega VLF transmitter

Jim M0BMU has posted a link on the LF reflector to a site showing the Omega beacon antennas and transmitter at Haiku Valley in Hawaii. This very accurate beacon system operating just above 10kHz. It has now closed being largely replaced by GPS. My house and entire garden would fit twice in the room shown as "the dummy load room".

26 Jun 2010

VHF NFD next weekend

Next weekend it is VHF NFD so there will be a good opportunity for some QRP DXing on the VHF bands. In past contests I've managed to work way up to Scotland from here with just a small halo and 5W. This sort of DXing sometimes requires going on to CW to complete contacts though. Best times, ignoring conditions, are usually early Sunday morning as the sun is rising, when tropo conditions are good, or late in the contest when stations are looking for new stations to work.

Kanga Products kits

The well known range of QRP kits from Kanga are now available again in the UK. These include the FOXX3 transceiver and the Sudden receiver. See the Kanga Products UK website.

Live 8.97kHz transmission from Germany

DK7FC is transmitting now (0800-1100z) on 8.97KHz. His signals are visible on his 8.97kHz grabber . Stefan is testing further improvements to his earth electrode antenna. The message is very clearly "73" sent in DFCW 600.

Nuclear submarines + UK Trident nuclear deterrent

There's a programme on BBC TV tomorrow about the design and building of the UK's latest nuclear submarine. The preview said that each costs 1 billion UK pounds to build!! Couple this with the 100 billion pounds we are likely to spend on upgrading Trident nuclear weapons and we are talking about a huge amount of money.  I find these sums on such weaponry obscene and plain wrong. If similar amounts were invested in the search for sustainable energy sources I'd be much happier.

25 Jun 2010

More 500kHz WSPRing with the earth electrodes "antenna"

This evening I've again been running my 500kHz QRP transverter into the earth electrodes separated by 20m of wire at about 1.5m above ground only. Reports from M0BMU (69km) and G0KTN (210km) confirm that this is only 6-8dB worse than my spiral top loaded 5m long vertical (i.e. ERP is now between 50-100uW). At the moment the only antennas I have up are a disconnected V2000 VHF/UHF vertical and this earth electrode antenna also used on 838Hz VLF, so the signal is definitely just what's coming from the loop formed in the ground.

German VLF earth mode test: 5.2 km on 8.97 kHz

Stefan DK7FC has been doing some experiments with around 50W to a 300m spaced grounded earth electrode "antenna"  in a remote location in Germany. Today his experiments were successful with his transmission of 30 minutes clearly received on his E-field probe receiver and grabber located in the city some 5.2km away.  See the report on his experiments at  http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF_5km_with_an_earth_antenna.pdf . Stefan can improve the electrode arrangement and increase current into the ground as well as run up to 500W. He's hoping to see the signal on the DF6NM VLF grabber located 174km away. If successful, this would be the first reported amateur radiated VLF DX using earth electrode antennas.

24 Jun 2010

VLF Earth Mode: 5.25km DX today with 4W

This evening I repeated my visit out in the fens with my loop seeing how far I could copy my 4W 838Hz beacon. After getting good QRSS3 copy at the same location 5.1km out as 2 evenings ago, I then tried going further out along the same fenland drove road. Although I managed to copy the signal at 5.25km this evening, no copy was achieved at any greater range despite travelling along several different lanes in many different directions. I'd like to know what it is in the roads that is helping - I assume water pipes, but it could be gas pipes or buried cables. What is clear now is that without these, the signal is absent more than 0.5km from home. This time I tried looking for the signal in far more places about 4-6km to the north of the village, but there was no trace of signal in this direction. Best directions are west (fenland peat) and south (chalk uplands). I've still to test to the east.

Another future test will be to try receiving the signal with a second pair of earth electrodes instead of the loop at some distance from home as one might expect stronger signals. This test will have to wait until the weekend though. If similar to results close to home, the 50Hz noise will be much worse though and this may prevent reception unless very quiet spots can be found.

Another beautiful QRP transceiver from AA1TJ

Menos es MAS is another fine QRP transceiver design from Mike Rainey AA1TJ. This really is about as simple as an HF transceiver gets with reasonable performance and QSOs in his log to prove it.  I like Mike's technique of using a development board to knock circuits together. This approach is fine for lower HF bands.

23 Jun 2010

Earth Mode DX map

This map shows the places round and about my QTH in Burwell (JO02DG) where I was, or was not, able to receive my 4W 838Hz earth mode signal in tests on June 21 and 22nd. Red dots here show attempts that failed, i.e. no signals detected, and green dots show where signals were successfully received and recorded. Best DX was 5.1km, but further is certainly achievable on QRRS3 with "utilities assisted" earth mode i.e. where ground coupling is enhanced by buried pipes and cables. Best DX with 4W into the 20m spaced earth electrodes using purely induction seems to be around 0.5km.

136kHz using the earth electrode "antenna"

This evening I was able to copy G3XIZ on 136.5kHz CW at 559 using my deaf (at 136kHz) FT817 fed from my 20m base earth electrode "antenna" used on VLF. I've made a recording and emailed it to Chris who is 46km away from me. Later this year I hope to transmit QRSS or CW on 136kHz, but the antenna needs some thought as I don't have much space.

22 Jun 2010

Earth mode VLF DX now 5.1kms

Today I managed to copy my 4W earth mode 838Hz signal at a range of 5.1km. QRSS signals were so strong that I was able to copy by ear my 10wpm CW beacon too! To copy the 10wpm signal I needed Spectran running with narrow bandpass filters. Without the filtering, all that could be copied was 50Hz noise.  At this range the signal level is definitely being helped by conduction through pipes in the roads and the main propagation is not by induction. Lots more information as well as screen shots and recordings on my sub-9kHz webpage.

21 Jun 2010

VLF Earth Mode: 3.6km DX today with 4W

My earth mode VLF DX increased to 3.6km today using QRSS3 and a PC running Spectran. TX was 4W into 20m separated electrodes in the ground. TX frequency was 838Hz. The 80cm loop and preamp receiver were set up in several places well out of the village in several directions and results well exceeded my expectations. Lots of information on my earth mode webpage including screen shots and sound recordings made using Spectran when out in the field.
This screenshot was from the roadside 2.5km south of the QTH. Signals were so strong (30dB S/N) that the signal was audible when Spectran's BPF in circuit (lots of 50Hz hum without).

20 Jun 2010

More 500kHz weirdness

Today I experimented some more with 500kHz WSPR using earth electrode pair arrangements rather than conventional antennas. In the end I was still getting reports from 210km away when using around 100uW ERP (maybe less) from a loop consisting of an earth rod outside the back door connected to about 7m of wire back to the bedroom with the other connection going to the central heating radiator. Why this works I have no idea! My latest theory is that this small loop is acting as a coupling loop to local overhead phone wires. I can't see otherwise how this "non-antenna" can otherwise work.

19 Jun 2010

Stable audio frequency tone generation (for VLF QRSS)

Next week I want to try QRSS3 with my earth mode VLF system to extend the range. As in the test this week,  Spectran software will be used my PC to filter and decode it. For a stable source I'll use a crystal and divide this down to sub-9kHz. Looking around for a suitable simple circuit I found G4HCL's very simple 1750Hz toneburst circuit which uses a 455kHz ceramic resonator (pulled slightly) and a 4060 IC as a divide by 256. With a crystal instead of the ceramic oscillator this should be perfect if followed by some filtering to produce a decent sine wave output. See M1GUR's page for more details.

18 Jun 2010

Earth electrode loop effective area at 500kHz

From some measurements of my earth electrode "antenna" this evening and some estimates of the ERP calculated from received field strengths 69km away, I've received an estimate of my effective loop area including that part that is within the ground. This was calculated by Rik Strobbe OR7T as 70m^2 in total, suggesting some 20m^2 of the loop was within the ground. These were Rik's calculations:
- 50uW ERP
- antenna is traded as a loop (gain = -0.4dBd)
Due to the negative gain (-0.4dB versus dipole) a loop antenna must "radiate" 55uW to get 50uW ERP.
Since the antenna feeding current is 0.15A the radiation resistance is 2.44 milliOhm (R= P/I^2)
The radiation resistance of a small loop is : Ra = 320xPi^4*A^2/L^4
where A = loop area (m^2) and L = wavelength (m)
For 500kHz Ra = 5*10^(-7)*A^2 or A = 1416*sqrt(Ra)
If Ra = 0.00244 Ohm then effective the loop area is 70m^2"

17 Jun 2010

Diagram of my earth electrode antenna for 500kHz and sub-9kHz

This is a hand drawn diagram of my earth electrode antenna for 500kHz and sub-9kHz. On 500kHz WSPR this has managed to TX a signal as far as G0KTN who is 210kms away when using my 5W QRP transverter. Sub 9kHz my 4W TX is audible by ear at 0.5km range on an 80cm loop.  This is a totally "stealth" antenna that is not visible at all to anyone looking at the property.

16 Jun 2010

Balloon SSTV from 30kms

From the Southgate News page:
Ed M0TEK and James M6JCX bring news of an amateur radio Slow Scan TV transmission on 434.075MHz USB that'll take place from a high altitude balloon at 30km on Thursday, June 17.
In addition to the 434.075MHz USB SSTV transmissions there's another telemetry beacon on 434.650MHz USB.
At high altitude the balloon may be receiveable by stations up to 300 kilometers away.
Ed and James write:
Just to announce that there is going to be a balloon launch Thursday, June 17, from Churchill, Cambridge at ~ 11:00BST. Onboard will be Nova 18 consisting of the CUSF Ferret tracker and a school experiment and also there will be Pegasus VII a SSTV payload. Normal flight profile is expect, burst altitude just over 30km landing just South West of Milton Keynes.

Screengrab of 1.8kHz earthmode transmission today

Today I modified my VLF TX so it could send either a 10 wpm or QRSS3 beacon signal. I also went out into the fields with my loop/preamp and a PC with Spectran to receive it. For the first attempt with a PC I went 0.3km away from home where the 4W signal from the earth electrode "antenna" could clearly be received by ear. With Spectran I could read the 10wpm CW signal with 20dB S/N in a 12Hz bandwidth, if my understanding of the Spectran settings is right. There is an audio recording here so you can judge the S/N yourselves. This suggests that with QRSS3 and really screwing the bandwidth down I should be able to do much better. My problem is knowing how to calibrate the soundcard etc and clearly I need a more stable source than my free running twin-tee audio oscillator.

500kHz WSPR - without an antenna!

Well, I'm amazed. This evening I connected my 500kHz transverter straight to the two connections of my sub-9kHz grounded electrodes and TXed WSPR. No attempt was made to match anything on the assumption that the two electrodes system looked not too far from 50 ohms resistive as measured between 1-9kHz.. Pout from the IRF510 is around 5W. What happened?

Three people copied me
- M0BMU, G7NKS and M0JXM with reports between -21 and -28dB S/N. The wire to the furtherest ground rod is at most 20m long and most of the way it is 1.5m above ground. Once again, this must be acting as a pretty effective loop mostly within the ground.  Screen grab of the WSPR log attached.

So, if you live on clunchy chalk soils like me then don't worry too much about big antennas, :-)

15 Jun 2010

Grounded electrode antenna on 500kHz

This evening I tried listening on 500kHz WSPR using the 20m spaced grounded electrode pair "antenna" in the back garden (earth rods 20m apart). To my surprise I decoded G3ZJO and G7NKS. Both stations were using just 1-2mW ERP. I'm tempted to try this "antenna" (actually a loop formed in the earth) on TX to see if anyone can decode me on 500kHz.

WSPR with the X80 and 5W

Well, here is a summary of my (intermittent) QRP WSPR beaconing tests since I erected my X80 vertical at lunchtime today:
  • Bands tried 80, 40, 30, 20, 17 and 10m (reports received on all bands tried)
  • Reports from 25 different stations in 14 countries and 3 continents
  • Best DX 6105km on 17m
So, a reasonable test for the antenna and I believe it is working out pretty well so far.


As a west countryman from Devon I love pasties. We occasionally make our own, but usually buy Ginsters which are not a bad pasty. For the VERY best pasty, you will be hard pressed to beat those made in the west of England by Ivor Dewdney. Fifty years ago I remember a trip shopping in Plymouth wasn't complete without eating one of these! They are still made the traditional way, by hand. Heck, I could eat one now.

SRC X80 multi-band vertical erected

My SRC X80 multi-band vertical was erected without problems this morning. Fed via about 10m of coax through the house and matched to my FT817 via the Elecraft T1 auto-ATU, it managed a decent match on all bands from 80-10m. Within 2 minutes of tuning it up I'd had two QSOs with 5W QRP CW: HA3FTA on 10m (599) and LA5CB (559) on 12m. So, promising results so far. The next test will be to try WSPR beaconing on the various bands as this is a good check of general performance.

UPDATE 1hr later: Tried WSPR at 5W on 28, 14, 10 and 7MHz and have had decent reports from around Europe on all these bands. I've just got a WSPR report from W8LIW on 18MHz at 6105km. So, it's doing a credible job.

See my webpage about the antenna: http://sites.google.com/site/g3xbmqrp/Home/x80ant

14 Jun 2010

6m WSPR - and tropo?

In between other things tonight I've been running WSPR on 6m. Interestingly I seem to be able to consistently copy G8JNJ 184kms away, presumably by tropo? He's also decoded me once. Don't think it is aircraft reflection as no Doppler evident on the WSPR display. Also managed to see and be seen by EA1FAQ. I use a V2000 triband vertical on 6m.

Twin tee oscillator

A twin-tee audio oscillator is a very useful item to have around the shack. Looking around the net for suitable circuit values yesterday I came across this page by G0XAN http://homepage.ntlworld.com/g0xan/twin-t.htm

I shall be using one this week with my CW keyer to send slow CW (QRSS) on 1.2kHz and 8.97kHz. For very slow CW I'll need a much more stable oscillator probably a crystal and digital divider, although many on the "Dreamers Band" are using a DDS source.

12 Jun 2010

A very young trainee engineer?

This afternoon I had some "help" from a budding radio engineer aged 2.5yrs - my young grandson. We were in the lab mending a toy fire engine (see picture) but he was more interested in twiddling the audio generator and listening to the tones and watching these on the oscilloscope. To see the video go to http://www.youtube.com/watch?v=tRwaT9s6ZHM

11 Jun 2010

Latest NOAA sunspot predictions for cycle 24

The very latest sunspot predictions from NOAA for cycle 24 make rather depressing reading showing a 95% probability of a peak smoothed sunspot number of just 91.8 in June 2013. By this autumn we should see counts in the mid 40s and the following autumn around 75.  10m transatlantic openings should be common again from this autumn, but the low sunspot peak suggests 6m openings will be much less frequent than in recent cycles. So, in my lifetime it is unlikely I'll ever see again the halcyon days of the peak of 1957-9 when conditions were remarkable.

Croatia on 500kHz

9A5K has been granted an experimental licence to operate on 493-510kHz as well as on the 5MHz band from June 10th.

Good Es today

Only had a brief chance to listen on 10m and 6m today but both bands were busy with Es signals from right across Europe. The season is well and truly underway now. A brief listen on 2m did not result in any DX being heard.

SAQ (17.2kHz) CW VLF transmission Sunday July 4th

There will be a further transmission from the historic VLF transmitter at Grimeton, Sweden on July 4th at 0900 and 1200 UTC on 17.2kHz CW with tune-up 30 minutes before each transmission. E-mail to: info@alexander.n.se or fax to: +46-340-674195 or via: SM bureau or direct by mail to:

Grimeton Veteranradios Vaenner, 
Grimeton 72

10 Jun 2010

SRC X80 antenna has arrived

Well, I'm very impressed with how quickly Snowdonia Radio Company despatched my X80 multi-band Rybakov HF vertical: it arrived on my doorstep early this morning only a few days after ordering it. I shall not be able to erect it until next week though as my little grandson is staying with us until Monday. All being well, I'll erect it on Tuesday.

9 Jun 2010

San Marino on 4m

The San Marino authorities have authorised 4m operation (100W max) until the Oct 31st 2010, on 70-70.5 MHz. T77C and others will operate from San Marino 19-20 June.

PLT-Interference Range Contest

The EMCIA have announced a contest to identify the interference range of Power Line Telecommunications - otherwise known as PLC or BPL.  See http://www.emcia.org/documents/News/Rules.pdf

7 Jun 2010

Useful multi-band HF vertical

The Snowdonia Radio Company is offering the SRC X80, a 5.8m long multi-band HF vertical matched via a 9:1 unun matching box. This sells for just £47, which is excellent value compared with similar offerings from the Japanese manufacturers. Such Rybakov antennas offer a decent match, easily brought to 1:1 VSWR using an auto ATU, on the higher HF bands. On the higher bands performance is quite acceptable considering the compromise in size. In the latest edition of PW Magazine G6MXL reports working plenty of DX with 50-100W using one.

5 Jun 2010

4m beacon in the USA

This news is about 4 weeks old, but I missed it!

A new 70.005MHz (4m) beacon  WE9XFT is operational from Virginia, USA, FM07fm. Callsign and a short message is sent continously in CW at 18 WPM/90 LPM. It's a radio science beacon for sporadic-E propagation purposes. ERP is 3 kW from a 3 el. yagi at 60°, i.e. Europe. The beacon will run 24/7 until Sept 1st. The beacon is non-amateur and sadly no 2-way QSOs can take place.  Reports via e-mail to WA1ZMS.

2-way QSO on the 8.97kHz "Dreamers Band"

DJ2LF and DF6NM held what was probably the first two-way contact on 8.97 kHz. The distance between them was 20.2 km, well outside the reactive near field zone (λ/2π = 5.3 km). In each case the radiated power was about 5uW. They used a special QSO procedure using dual frequencies. Congratulations to both stations.

4 Jun 2010

Noctilucent Clouds and microwave DX?

Noctilucent, very high altitude, night time visible, clouds are becoming more common and at lower latitudes. This may be a result of climate change. One phenomenon associated with these is strong microwave radar echoes, raising the possibilty of very long distance DX by reflection from these on bands like 10GHz. This is an area ripe for experimentation but I am unaware of ANY groups anywhere investigating this exciting new propagation mode.

There is a  link between noctilucent clouds and the solar cycle with NLC activity peaking just after solar minimum, possibly because low solar activity allows the upper atmosphere to cool, promoting the growth of ice crystals that make up the clouds.  See http://spaceweather.com/

2 Jun 2010

SWLing in the 1960s

Back in 1961/62, when I first got interested in shortwave listening, a friend of mine and I had an intercom across our back gardens with a long piece of twin flex and a couple of DLR5 headsets. Now my friend's dad was a bank manager and he was "rich". Paul's dad bought him a Perdio 102 multiband receiver which made me green with envy! So, late at night, under the bedclothes, we'd both share listening on the Perdio102: Paul would put it to listen on 2.182MHz (the trawler band calling frequency) and we'd often hear an emergency and the local lifeboat being called out. We'd listen for hours. On this same receiver I recall being amazed at hearing South America hams on AM. We both became hooked and not many years later got our licences. See also the radio museum pages at http://www.radiomuseum.org/r/perdio_multiband_102.html

HF transceiver ideas site

Vanyi Istvan Vanyi YO5OFJ has an excellent website with links to a whole list of HF transceiver designs from around the world. Most are QRP designs with links to the originating sites.

Amateur Radio Wiki

Not sure how I'd managed to miss this amateur radio wiki site before, but it looks worthwhile bookmarking.  Being a wiki, it allows users to add or modify content in a similar way to Wikipedia. It has some useful links and data.

Elecraft K1 stand idea

Someone was asking about a stand to angle the Elecraft K1 transceiver at a suitable angle on the operating desk. A commercial version is available, but I found a simpler solution: two large rubber feet at the front and two small ones at the back. This angles the rig up about 10-20 degrees and is perfect for operating on a desk.