50MHz aircraft scatter

Interesting piece on G3ZJO's blog about 50MHz aircraft scatter using WSPR signals. He has a nice waterfall display showing the strange things that happen to a WSPR signal when aircraft are moving.

WSPR versus CW - what's the improvement?

As WSPR is so effective I asked Joe, K1JT, what the difference is between WSPR and "ear-and-brain" CW. This is his very helpful reply:

"For an answer to your question about relative sensitivities of CW, WSPR, and some of the other modes implemented in WSJT, let me suggest going to the "References" link on the WSJT web site, http://physics.princeton.edu/pulsar/K1JT/refs.html ,
and select reference #11. Table 3 on page 9 gives the information you asked about. The difference given there is about 11 dB, in favor of WSPR over ear-and-brain CW. For most operators, the difference is more like 15 dB."

OK1IAK's tiny WSPR beacon TX

Vojtech OK1IAK has created a tiny WSPR beacon TX based on the KD1JV Altoids tin ATS-3b transceiver kit. He uses the ATS3bv-1.5 firmware. For those not familiar with this creation, it is a tiny 6 band CW/digital transceiver kit fitting into an Altoids tin. See OK1IAK's alternate firmware for WSPR with this rig.

Heard in VK on 40m QRP again

At 1834z, 30 mins earlier than last night, VK8CH reported my 5W WSPR signal at SNR -27dB, which is 1dB lower than last night. A few hours later, VK8CH copied my 2W (33dBm) 40m WSPR signal at SNR of -24, -27 and -28dB over a period of some 20 minutes. PY2GN has heard me twice tonight already on 30m WSPR, again using 5W. W1XP was copying my 1W 30m WSPR signal at a SNR of-17dB.

All this on 15m of end-fed wire strung from the gutter to the washing line post at the bottom of the garden!

40m QRP WSPR signal copied by VK8CH

This evening, VK8CH (Australia) copied both my 10W, then 5W QRP 40m WSPR signals. DX was 13800kms - not bad for a small, 15m long, end-fed wire strung down the garden only 6m at the highest end and 2.5m high at the far end!

What constitutes a QSO?

Having been experimenting with WSPR beaconing, and having a LOT of fun too, I started to ask what constitutes a QSO?

For example, this evening on 160m I both sent and received callsigns, locator grids, frequencies, power, date, time and reports with G8IHT and G4BOO using WSPR. You KNOW the other station has received it from the on-line WSPR database. This was in WSPR MEPT (beaconing) mode and not using WSPR QSO mode, which I've yet to try.

Now, is this a QSO formally? My feeling is no, yet all details were exchanged and received by both parties. Certainly as much detail as would be exchanged in an EME or MS QSO using modes like JT6M, although no RRRs were sent.

Views please?

6m WSPR testing overnight (Aug 12/13)

Overnight I'll be repeating my WSPR mode MS/Es testing, this time with transmissions on 50MHz running 5W for 20% of the time from around 2100z to 0800z. If you have WSPR software, please set your RX to 50.2930 USB and let it run through the night to see what propagation exists.

UPDATE: Not a single report received or obtained for anyone else on 6m overnight. Then 4 hours later I realised I been plugged into the 10m halo :-(

10m WSPR QRP DX - Perseids MS?

I ran WSPR with 5W out (20%) on 10m overnight and was heard twice by F4VNS in JN36hc (see report screen). Although I did not decode anyone on 10m overnight, this may be because there were few stations active on 10m WSPR. The few whispy traces seen suggest doppler shifting (possible MS)?

Anyone know when the Perseids peaked in Europe? I wonder if between 0230 and 0430z?

JT6m Perseids MS

Just turned on the FT817 and JT6M mode and copied HB9AGE within the first few seconds on a strong meteor burst. There will be plenty more tonight. The picture shows the capture of HB9AGE's CQ call here a few minutes ago. Also heard M0RJV, G4BAO (local) and PA5JS, all on JT6m.

10/6m WSPR

During the next 24 hours I intend to try WSPR mode beaconing on both 10m and 6m to see if I get any success during the peak of the Perseids meteor shower. I've no idea how this mode will work with MS and a basic QRP system with small antennas. Should you get a chance, do set your WSPR system to listen on 10m and 6m and log any reports to the WSPRnet logging site. Set your RX to 28.1246 MHz USB or 50.2930 MHz USB to receive WSPR signals.

Although probably not by MS propagation, my 10m WSPR signal was copied by S51CN tonight at 5w, 1W and then 50mW. At my lowest power setting the SNR was -22dB, suggesting that even 10mW would have been copied, but I've now run out of attenuators so can't get any lower tonight!

Bojan, S51CN kindly sent me a screenshot of my signals in Slovenia (see left).

Joule Thief circuit

This month's Practical Wireless makes reference to something called the Joule Thief circuit which allows a very nearly exhausted single cell battery to run a white LED. The article is in G3RJV's regular column. The nifty circuit only needs 4 parts. For a video describing how to build this, see this YouTube item. Another useful resource is http://www.emanator.demon.co.uk/bigclive/joule.htm from which this image was taken.

6m JT6M reception

A year or two back, during the winter months, I listened to European 6m DX via random meteor showers using the digital mode JT6M, listening on 50.230MHz. Even though I only have a V2000 triband vertical, I heard several countries then with the best DX being EA, I and HA listening for about 30 minutes in the evening. This week there is a meteor shower due around Aug 12th (Perseids?) so I will give it another go to see what can be heard with my basic setup and antenna.
At the moment I don't think it is worth trying to TX as the most I can run is 10W.

WSPR Success

DH5RAE (990kms away) logged my 5W into just the 10m band halo TXing WSPR on 30m a few minutes ago. So, the system is now fully working, despite the appalling antenna for 30m. Then in the next timeslot I was received by OH2BMH (1759kms away). WSPR is going to be one heck of a lot of fun on bands like 10m and 6m with QRP when the bands open up.

LATER: In three sessions of "30m WSPR beaconing" I've now been received in 5 European countries at distances between 594 and 1759kms. The image on the left is of my WSPR log.

More WSPRing

Well, thanks to some help from others I've figured out how to TX a WSPR signal.

For use with a SignaLink USB interface and VOXing TX you need 0, 2, 4 as the settings for PTT, RX and TX and you need to restart the WSPR program for the changes to take effect (this was my problem).

WSPR DXing

My best WSPR report tonight was of DL6NL who was running just 50mW on 7MHz. I could receive him OK at 733kms when using my 10m band halo antenna.

WSPRing

Today I made my first foray into WSPR mode (Weak Signal Propagation Reporting).

I've managed to decode WSPR signals on 30m and 40m OK, but every time I tried to TX with the program it bombs out and wants to send Microsoft an error message. I'm using a SignaLink USB interface (working fine on PSK31) and have set the WSPR PTT option to "0", which should allow VOX operation on TX via the SignaLink USB interface rather than via a COM port. Anyone know why this fails to work and crashes the program?

WSPR is a mode which allows specially encoded very weak signals to be decoded and then the resulting report uploaded to a central database. So, for example, you TX with a QRP mW signal on 10MHz and someone receives the WSPR message. Using the software, a report appears on the internet, so you know how far the signal reached.

See http://www.g4ilo.com/wspr.html for a good introduction to WSPR. Spots (uploaded by the program or manually to the internet) can be seen at http://wsprnet.org/meptspots.php

6m CW

Last night I heard TF2JB weakly calling CQ on 6m CW on an otherwise empty band, but I did not work him. This afternoon at 5pm I called CQ on 6m CW having heard the SK3SIX beacon pop up out of the noise and was answered by SM2GCQ. So, even with 5W, a CQ can get a QSO on 6m in an almost empty band. Spor-E is still around folks, if less frequent than a month or so ago.

LY3LP's blogsite

This is a very interesting blogsite with lots to interest QRPers. I like the tunnel diode TX and the 6m projects. Some of the wind turbine blades are unusual. See http://sa555.blogspot.com/

1860 voice recordings

I missed this news from March 2008 about the earliest recordings of the human voice made in France in the late 1850s and early 1860s. American researchers pieced together a 10sec audio clip of a French folk song which they believe is the oldest recognisable recording of the human voice. A young woman sings from the 18th century folk song Au Clair de la Lune. It was made in 1860 by Edouard Scott de Martinville on a device he called a phonautograph. Listen to the sound clip here:
http://graphics8.nytimes.com/audiosrc/arts/1860v2.mp3

Edison's recording of himself reciting 'Mary had a little lamb' were many years LATER than these very early recordings. Totally fascinating!

Pye PF1 and PF8 handhelds

I've justed added a couple of pages to my website on two Pye Telecom PMR products I had involvement with in my early days in the development labs there.

See Pye Telecom PF1 Handhelds and Pye Telecom PF8 Handheld

For far more information on Pye Telecom see the website http://www.pyetelecomhistory.org/

Incidentally there is a drive to set up a permanent museum of radio history in the Cambridge area in which Pye Telecom products would be featured. £30k is needed to get this project off the ground. See the Pye Telecom History pages for more information on this project.

Sunspots and solar flux

The recent upturn in the sunspot count seems to have stalled a bit, although the rolling average does appear to point to an upturn which should result in improving conditions this autumn and winter. Solar flux levels remain below 70 still and don't seem in a hurry to rise.

However, 6m is still lively with sporadic-E and continues to liven up this magic band.

See http://www.swpc.noaa.gov/SolarCycle/

Another SixBox QSO

This afternoon I worked G3PTQ in Bottisham, 6kms away with the 50mW Sixbox AM transceiver. Report was RS41 (weak, but 80% readable). Then Terry mentioned he was using a low horizontal dipole, so signals could easily have been some 10-20dB (2-3 S points) stronger had he had a vertical antenna. This little transceiver is definitely proving useful for local 6m contacts.

IOTA contest - 10m QRP

For a few hours today I managed some operating on 10m QRP in the IOTA contest. No great DX (best was Cyprus) but I did work a couple of stations when running just 500mW pep. They didn't appear to notice the low power and still gave me 59! For a little while I tried calling some of the stronger stations with 50mW pep, but in the limited time I had the best I got was a G3X.. QRZ? at that power. With 50mW on CW it would have been quite easy.

Interestingly I heard GD (Isle of Man) and GJ (Jersey) on 10m SSB today. Both are usually too near to work or hear. Unfortunately I didn't managed to raise them. Pity as they would have been new DXCC entities for me on the band.

SixBox (6m) and FredBox (2m) - /P tests

This evening I managed 16kms contacts with both the SixBox 6m 40mW AM transceiver and with the Fredbox 2m 10mW AM transceiver. QSOs were from Aldreth, Cambs, to Swaffham Prior.

Signals from the SixBox were copied by Andrew G6ALB when I was TXing with a 6m 1/4 wave antenna on a magmount on the car roof. On the superregen RX there was solid copy of G6ALB's 6m AM signal. Andrew uses a Diamond V2000 vertical, which recent discussions have confirmed are NOT as effective as a true 1/2 wave vertical on 6m. Clearly if Andrew had even a 2 el beam the QSO would have been a very decent one.

After finishing on 6m QRP, we moved to 2m AM to try some tests with the 2m Fredbox. A solid QSO was quickly achieved with the 10mW Fredbox using the 6m 1/4 wave antenna on the car magmount. This acts as a 3/4 wave antenna on 2m. I then tried the same antenna on the Fredbox handheld. Again, a solid 2-way QSO at 16kms distance. Switching over to a 1/4 wave whip on the handheld Fredbox resulted in a weaker, but just usable signal and QSO (same signal level as on the 6m SixBox). Finally, I tried the Fredbox handheld with a small helical antenna. Although Andrew could just detect this, no real QSO was possible.

So, with the V2000 in use at the far end of the contact, 40mW AM on 6m was not as strong as 10mW AM on 2m. Notheless, it was fun to give both rigs a portable outing and make some contacts.

The picture shows me during the Fredbox QSO using the 3/4 wave whip on the Fredbox.

Ham radio and young people?

Last night I gave my "Kitchen Table Minimalist Radio" talk at the Peterborough Radio Club. Everyone was very welcoming and, to my surprise, there was a very good number of people there to hear me. Afterwards quite a lot of the group came up to take a look at some of the homebrew gear that I had made and talked about.

One thing that struck me, again, is how few young people there were there. Having given similar talks in 3 clubs in East Anglia now, one can count on one hand the number of youngsters (boys/girls) at the meetings. OK, it could be my subject did not appeal to them, but I think this is a more general issue and one that we HAVE to address seriously or the hobby will die with us in another 20 years or so.

The RSGB (and I suspect the ARRL) have initiatives such as GB4FUN to help this shortfall of youngsters coming into the hobby. I feel that it is in the schools, youth clubs and scout groups that we have to inspire kids with the magic of radio.

Even after 50 years, radio still is magical for me. I just wish I could help to "spread the word" to today's young people. Also, industry NEEDS new radio engineers before the oldies die out!

V2000 vertical on 6m

Several recent local tests on 6m lead me to believe the V2000 triband vertical is not that good for local working. It is fine for DXing but signals around 15-25 miles away are weaker than I'd expect. Maybe the polarisation is not as truly vertical as I had believed? I can access the 6m repeater 25 miles away OK and can work stations, but at levels lower than I would have expected. Essentially the V2000 should be like a vertical halfwave on 50MHz, so this is a bit puzzling. In the past I had assumed it to be a pretty good antenna, but maybe not.

SixBox testing and "super" 6m DX

Back home in Cambridgeshire now and, sadly, was unable to find anyone within a 15-20 mile radius when in S.Devon with whom to test the SixBox QRP AM rig. This despite calling for several DAYS on the local 6m and 2m repeaters.

The Torbay 6m FM repeater was a good signal and I could access it well, but I heard not one person using it! No-one even replied to a call through it.

I had plenty of 6m DX QSOs on SSB using the magmount on the car and 5W though, and heard (but not worked) some remarkable transcontinental DX on the band from South America.

So, back to more modest aims, I shall be on the lookout for stations in East Cambs to do further range testing the SixBox. Let me know if you have 6m vertical and AM and are likely to be workable with 50mW AM from East Cambridgeshire so we can try a test. I am located in Burwell and have a reasonable takeoff to the west and north.

Peterborough Talk - Wed July 22nd

This Wednesday I am giving my "Kitchen Sink Radio" talk at the Peterborough Radio Club. I will put the presentation on my website after the event. At the moment I am hoping my wife's WinXP PC survives as it has two keys which packed up last week. I need this PC for the slideshow. Arghhh!!

6m Super DX

For the last few days I have been in South Devon on holiday. Some evenings I have been out looking for skeds with the SixBox 6m QRP AM transceiver but two tests failed even with 2W AM from the FT817 and the 1/4wave magmount, so no QSOs with the baby rig yet. However, I managed several European DX QSOs with 6m QRP SSB, all with good reports.

Last night was exceptional on 6m: YV4DDK, FM5AA and 9Y4D all coming through at good strength (at times) on 6m SSB with just a 1/4wave magmount antenna! Although I tried calling the YV4 at one point I knew it was pointless with all the super-QRO stations with big beams calling them. Still, it was good to HEAR such super-DX on 6m (8000kms) with such a simple portable station.

6m AM and noise

Two local tests with stations on 6m AM have shown just how noisy the band can be when using this mode. M1KTA was 18kms away and M1MAJ around 15kms yet both were not strong on the vertical V2000 antenna on 6m AM even when they were using FT817 rigs at 2W AM. We were going to try the SixBox but signals would have been too weak. Switching to USB made a lot of difference (better) unsurprisingly, as the noise level reduces with the bandwidth.

This goes to show how AM signals do need to be strong to overcome the band noise: when signals are a decent level AM is a fine mode, but it can be hard work when they are very marginal with lots of noise in the background.

6m QRP AM tests - Cambridge area

Anyone around near Cambridge/Newmarket/Ely with a 6m vertical antenna who can help me range-test my very simple homebrew 6m QRP AM rig in the next couple of days? SixBox details on this blog and my website. It is working OK but I want to find out how far it gets locally.

Freq: 51.125MHz (sorry only xtal I have at the moment)
Power: 50mW AM
Ant: V2000 vertical
Loc: Burwell, 10m NE of Cambridge, JO02DG

Grandson 2

Our second grandson,  is on holiday with in-laws in Australia. We've just been sent this nice picture of him. He is clearly enjoying himself.

SixBox QSO 3 - sensitivity testing

This evening I had a third QSO with G6ALB using the SixBox 6m 50mW AM transceiver. The main aim was to test the receiver sensitivity since fixing an issue last evening. Andrew first called me using his FT817 on the lowest AM power setting and he was good copy. He then switched over to a modulated AM signal generator at 7dBm level (5mW). This was easily copied on the superregen RX. Even with a 10dB pad in at my end I could still copy the signal i.e. at an equivalent of 0.5mW from Andrew 2 miles away. So, without accurate test equipment I can safely assume the RX is detecting low uV level signals. I must work out the path loss.

Having got the SixBox working pretty well it now remains to see how far it can reach. I am really pleased with this simple project. It is very satisfying to work people on AM using really simple homemade equipment built with minimal test equipment and using parts which cost very little.

The current TX frequency is 51.125MHz. I need to buy a crystal for the 6m AM working frequency (50.57MHz in the UK or 50.4MHz in the USA).

Sunspots creeping up

Noticed the sunspot numbers trend recently? Whereas a few months ago there were weeks and weeks without a spot, now there are spots on a high proportion of days and the general level of active cycle 24 spots is creeping upwards. All this bodes well for this autumn when I hope we'll see some F2 transatlantic propagation on 10m again on many days, with plenty of US and Canadian stations workable with QRP - a sure sign that the old sun is waking up.

6m Sixbox AM QSO No 2

RS59 from G6ALB this evening with the SixBox 50mW AM transceiver. In putting the transceiver in its box and adding the RX tuning I inadvertently removed the coupling cap between the RF and and detector stage so the RX was a little bit deaf. I will add this back tomorrow and expect sensitivity to be back to low uVs level. Even without it, I could hear signals of 2-3mW out from Andrew.

Next week I am in Devon on holiday, so will be looking for some 50MHz AM QSOs with the SixBox from clifftop highspots. I will set up some 6m AM skeds using the local VHF and UHF repeaters.

10m AM Net in S.London (Wednesdays)

A 10m AM net has been started in South London, UK by Gary G7IRG. It meets on 29.05MHz (AM mode) on Wednesdays at 9pm local time. Last week the net had 3 people on: G7IRG, G0KRT and M0GPG. If you live in this area, or indeed anywhere, why not see if you can hear the net and give them a call?

When 10m is wide open, as it will be in a couple of years time, the band between 29.00 and 29.1 MHz will be filled with AM stations from around the world.

6m when the band is quiet

6m is a band ripe for exploitation when there is no DX around. When there is sporadic-E or F2 DX about, people use the band in thousands and some have worked DXCC. However, when conditions are not good, it is left to a few dedicated enthusiasts to work random MS and tropo and ionospheric scatter mode QSOs using QRO with modes like JT6m. The amount of LOCAL 6m activity, at least here in the UK, is very low indeed.

We have 2MHz of band in the UK (4MHz in the USA) and it is a pity more use is not made of this fine band for local QSOs using simple QRP homebrewed equipment. It is an ideal band for QSOs up to around 20 miles or so and much quieter than 160m or 80m, which can be very noisy these days.

3 transistor SSB transceiver

http://www.intio.or.jp/jf10zl/3trssb.htm

The website of Kazuhiro Sunamura JF1OZL is magic and contains some superb ideas for QRP enthusiasts. Every time I return to this site I find something to enjoy and to inspire me. Take for instance the 3 transistor 6m transceiver he describes: it is wonderful. Kazuhiro San, if you read this THANK YOU for your great ideas.

10m or 6m QRP DSB ideas

Having finished my SixBox 6m AM transceiver, my mind is now turning to ideas for either a 10m or 6m QRP DSB transceiver. I have already breadboarded a 10m version in separate sections (RX based on the Neophyte RX, a DSB TX based on a single balanced diode mixer), but I have still to breadboard a mixer-VFO based on the NE602 which would be useful for either band. Actually a fundamental crystal x2 would give around 25-30kHz shift on 28MHz and around 50kHz on 50MHz, so this may be a simpler, and adaquate, route. However crystals "to order" are expensive these days, although the spec (temperature, cut frequency accuracy, etc) would be very low.

Today I noticed another 6m DSB schematic from a Japanese ham. There are plenty of good ideas from JA land where, despite commercial rigs, homebrewing is still in strong. See http://www6.plala.or.jp/jr8dag/micro6dsb/mi6dsb02.htm for JR8DAG's schematic. In my view, this is a rather complex schematic and I am sure it could be simplified.

SixBox 6m AM QRP rig now boxed

Today I complete this project and put the 50mW AM transceiver into a small diecast aluminium box. Using a 9V battery inside the box the rig puts out about 20mW. From an external supply it is about 50mW. The polyvaricon tuning capacitor works very well and the RX tunes from around 45MHz to 70MHz. Already it has been useful as an indicator of Band 1 activity.

Overall, I am pleased with this little transceiver. It was all done with the most basic of test equipment and is a circuit that should be easy to copy. Now to try to get some local 6m AM activity going! It would be very nice to make a PCB for this project. I'm thinking about it....

My next project is either the long intended 10m DSB rig or a DSB version of this 6m AM rig. However, to be useful this would need VXO control and a 3rd overtone xtal will not pull very far.