17 Nov 2011

Google Sites website design

My wife sings in a local choir called the Cambridgeshire Choral Society. They have had a website for some years but it had not been regularly maintained, so I was asked to create this new one. This I have just done using Google Sites. Although I'm no website expert, Google Sites allows quite a credible website to be created without knowledge of HTML coding. I am quite pleased with the result and hope it encourages a few more people to attend the concerts and join the choir.

Their next major concert is in Ely Cathedral in March 2012 when they will be singing Elgar's famous "Dream of Gerontius" which is a wonderful choral work. They are also singing Britten's "St Nicolas" in late January 2012.

In the next few months I hope to tidy up my QRP website and give it a refreshed look.

IC703 Sold

For around 6-7 years I've owned and used an IC703 10W QRP radio as part of my station. Although I have worked all over the planet with it on SSB and CW, it had not been used anything like as much as the FT817, so I decided to "de-clutter"and sell it.  It was bought by a local friend who hasn't got any HF SSB/CW gear apart from a homebrew rig for 20m.  I had thought of trading it in, so offered him the rig at the trade-in value. If he doesn't get hours of fun and enjoyment from it, especially on 10m at the moment, I'd be very surprised. You see very few of these transceivers available on the second hand market, I guess because owners hang on to them.

UKNanowaves Group

G0EHV's lightbeam kit (from the UKNanowaves group photos)
Today I joined the UKNanowaves Group which is dedicated to optical communications.  There is a lot of useful information on this group in the postings and in the files and photos sections. Reading the membership list I noticed several local amateurs interested in optical comms, so when I get my equipment for 481THz working credibly I will have a good chance of some QSOs locally.

Today some of my optical comms electronics parts arrived so I hope to start experimenting with these on the bench shortly. Most gear built for 481THz is simple and homebrew. Apart from designs using transverters to HF or VHF, all kit is in the 0-40kHz frequency range, so easily engineered with simple test equipment. Perhaps, like VLF and LF, this is partly why it appeals to me.

16 Nov 2011

137.5kHz transverter desense - fixed

This afternoon I fixed the problem with RX desense by adding a relay to switch the RF input and to turn off the PA supply when not on TX. It has fixed the RX sensitivity issue and added about 10-15dB to RX sensitivity using the transverter. PA0A was about 30dB S/N on QRSS and DK7FC about 20dB S/N on QRSS. M0PPP is now a better signal with me too on WSPR. The TX is still running at 500uW ERP and GW0EZY is copying me in mid-Wales OK (251km) this evening on 137.5kHz WSPR.

15 Nov 2011

137kHz Transverter RX Desense

When testing my transverter on the bench today I noticed the receiver was being desensitised by the undriven TX strip. I don't switch the TX part off when on RX, I just don't apply 10MHz drive into it. There must be some source of low level noise from these stages when on RX as the desense is around 10-20dB. Despite this I am still able to copy M0PPP at 182km pretty consistently these days on 137.5kHz WSPR. I need to fix this problem before this project is boxed and "finished". When the TX strip is powered down the sensitivity is very good indeed.

The 481THz Band

My tests on 137kHz WSPR are now all but completed and I do not intend to take this work any further now I've "got the measure" of what is possible. I shall put the transverter in a box after a tidy up and use it periodically over the winter.

Now I am about to start something new: 481THz band communications! This is 623nm red light for the uninitiated. This evening I've made a start by ordering some suitable components to allow benchwork to start next week. My initial tests will be low powered beaconing with a portable receiver walking down the road. Assuming this is promising, I'll then refine the kit and organise optics to give some "antenna gain" to allow much greater range.

There are a lot of resources on the internet about light beam communication, especially using high power LEDs and there was an excellent series of inspiring articles about this in the March-May RadCom this year.

14 Nov 2011

10m Chirpy Measurements

Last week G6ALB made a copy of my Chirpy 14 component transceiver for 28MHz CW. Andrew had access to some better calibrated test equipment and carried out some RF power and sensitivity measurements both on his version and on my second original unit - the first was just a rat's nest on the bench.

Both on my version and G6ALB's version the measured RF power out was in excess of 200mW, which is around 2-3dB more than I had crudely measured. The RX sensitivity on both was such that below -100dBm (around 2uV) was audible in our earpieces in a quiet room. Backwave carrier on TX was rather too high at around -10dBm. Second harmonic was also only around -6dB, so a low pass filter is really a necessity apart from casual short tests.

It does seem that the simple design is reproducible and its performance not at all bad for something this simple. The only major shortcoming is the chirp.

12 Nov 2011

Ten WSPR reports now on 137.5kHz

This evening G3WCB (101km) reported my 137.5kHz WSPR signal for the first time bringing my total number of reports on this more difficult band up to 10. My ERP is currently around 500-600uW, although I hope to run the transverter PA from around 20V tomorrow which should increase the ERP by around 3dB.

These are the reporters so far:

G6ALB
G3WCD
M0FMT
G3XIZ (46km)
G3XVL (69km)
M0BMU (69km)
G3WCB (101km)
G3YXM (148km)
M0PPP (182km)
GW0EZY (251km)

10 Nov 2011

137kHz WSPR - big SUCCESS at last!

After yesterday's disappointments today has been a whole lot better on 137.5kHz with my best WSPR DX report ever and a report from my second DXCC country on the band.  First several reports from GW0EZY in mid-Wales (251km) and then one from M0PPP in the north of England (off the side of my TX loop too - 182km) who I heard last night for the first time.  I've copied him several times tonight as well as PA3EGO. The transverter now puts out about 20W, but the ERP is still only around 200uW based on the loop current and enclosed area. I'm tempted to put it in a box at last as I now know this system is capable of decent range on a good night like tonight.

9 Nov 2011

Struggling on 137kHz - time to move on?

Today I did some changes to my 137kHz transverter and put it on the air this evening for about 4 hours sending and receiving 137.5kHz WSPR. Power from the PA is now around 20W and the ERP must be around 200uW.  I was really quite hopeful that, with enough stations active on WSPR tonight, I might get a few reports.  The band was indeed quite busy with a few stations like G0KTN and G3WCB who have regularly copied my 500kHz WSPR on the band and looking.  What a disappointment! Not only did I get not a single report, but I was unable to copy any of the active TX stations like F5WK or M0PPP. The latter was visible as a trace but not strong enough to decode.

Without increasing the power another 6dB at least to around 80W and improving the antenna considerably I am now of the opinion that, QRSS30 apart, 137kHz is not going to be a success. My feeling is I need at least 20-30dB better system performance (TX power and antenna efficiency that is) to even start to approach the level of reports I manage on 500kHz. So, do I try just that bit more or do I throw in the QRP towel on this band? I don't want to run lots of power and I don't want to erect a monster antenna: I was hoping my unobtrusive loop would have done me as well as it did on 500kHz, but clearly not.

I am beginning to think that this really IS a band where you need lots of power to make a success of things.


UPDATE: Just as I finished writing this I manage to decode M0PPP twice at 182km.
2252 -27 -0.5   0.137562  1 M0PPP IO93 17





7 Nov 2011

Simple VLF Receiver

SM6LKM's excellent PC based VLF receiver
In testing my Chirpy 10m transceiver, I used the simple PC based VLF receiver by SM6LKM as a bolt-on SDR. This little VLF receiver works very well as a stand-alone VLF receiver that tunes the 0-22kHz frequency range. Simply by sliding the cursor to any frequency it produces an audible signal just as you would get by tuning a conventional receiver.  Bandwidths are adjustable down to around 300Hz. For my video showing this in action listening to VLF signals (via my loop and small preamp) see http://www.youtube.com/watch?v=TDxRhQYg7lQ. With the SM6LKM VLF receiver you can clearly hear the Omega beacons around 11-14kHz, SAQ when transmitting on 17.2kHz, and various MSK military signals around 18-22kHz. It has also proved useful when carrying out earth-mode (through the ground) VLF communication tests.

6 Nov 2011

A good night on 500kHz WSPR

Not bad for 2mW ERP on 500kHz and a smallish wire loop antenna!
Very good activity levels again this evening on 500kHz WSPR with 13 unique stations reporting my signal in 6 countries. Best DX report was from OH1LSQ at 1733km, the first time this season.

I really must make an effort to get the 137kHz WSPR activity stirring. Maybe if I can get my ERP up this next week I'll swap over to that band for a few nights and see what turns up. Mind you, the WSPR activity on 137kHz is very low currently with most people using QRSS beaconing.

The "Chirpy" 14 parts QRP 10m transceiver video

This is a short video showing "Chirpy" (XBM10-2), my 14 component 28MHz CW transceiver. More details can be found at my website http://sites.google.com/site/g3xbmqrp/Home/xbm10_2.  Best DX is still IT9QAU/QRP but I am hoping for further soon. This is a simple project and, as with all very simple radio projects, it is a compromise between cost, complexity and performance. Nonetheless it DOES work remarkably well for something so simple. AM breakthrough is almost non-existent too, which was a bonus. Couple the audio into a PC rather than a crystal earpiece and  as a bonus you have an SDR receiver capable of copying from about 28.040-28.080kHz. Why the name Chirpy will be evident when you hear the keying!

5 Nov 2011

Elecraft KX3 or FT817 successor?

For some time now we've been expecting the successor to the FT817 to appear on the market as the current offering is now over 10 years old, with just a minor update in this period. Sunspots are rising fast now and I'd expect Yaesu-Vertex to release this within 6 months or miss a big window of opportunity.  The potential sales volumes are very large indeed as a large part of the amateur community owns an FT817 and would aspire to upgrade.

One wonders how Yaesu-Vertex is viewing the Elecraft KX3 and whether any changes to their new product will be made as a result of the KX3 pre-release data. The KX3 does look impressive but its form factor may not appeal to many. It also looks very "square" and Elecrafty! Although it can be used handheld, I understand you have to plug in a local microphone for example - a bit clunky for true handheld portable use, although you need an external mic with the FT817.

It is widely assumed that an FT817 successor will have a Li-Ion battery pack (2hr charge), built-in wide range auto ATU, good DSP features and possibly 70MHz coverage. The form factor is unlikely to be very much different from the current model, but with more inside.

Does anyone have any inside knowledge of Yaesu's release plans? If they don't get a move on the KX3 will steal the show. The KX3 is due to be released at the end of 2011 and order placement is starting very soon.

500kHz humming tonight

WSPR reception at G3XBM tonight - busy on 500kHz!
This evening the 500kHz band is VERY busy with lots of stations on WSPR.  At the moment there are over 20 active stations with 7 stations TXing.  EI0CF and G4WGT are being copied in Russia at over 2500km despite low ERPs.  My own 2mW ERP signal managed to be detected by GM4SLV (896km) and by many others in the UK and Holland.

Another 10m QRP transceiver built

Yesterday I built another simple 10m CW QRP transceiver. This is similar to the Tenner on my website with some improvements. This time the power out is QRO (well 600mW!) and the receiver a direct conversion one built around an SBL1 with passive LP audio filter and 3 stages of audio gain. The VXO, run from a regulated 5V supply, uses a fundamental 28.060MHz crystal which pulls from 28.040-28.070MHz with a sensible RX-TX offset (happens automatically) of around 800-1000Hz. Chirp is better than the simple XBM10-2 as the VXO is better regulated and the PA is a separate stage. Yesterday I worked RZ3QZ before the RX was finished and got reports on the reverse beacon network from W3OA. This morning a full 2-way QSO with UR5IDU (him 579 me 549).

UPDATE 1520z Nov 5th: This rig is working very well with 7 two-way QSOs on 10m CW in the log already since 1140z today. There is a Russian contest and the band is busy with Russian stations. Reports are all 599 of course but no repeats needed so far.

2 Nov 2011

Chirpy (XBM10-2) improvements

28MHz "Chirpy" Transceiver with tuned antenna match
In the last day I  have made some changes to my ultra-simple CW transceiver for 28MHz. Power output now is around 120mW (was 60mW) and the RX sensitivity about 3-4dB better. Both changes are a result of better matching the tank of the oscillator/mixer to 50 ohms using a tuned circuit with a suitable tap rather than a 100uH choke. At the moment the component count is 14 total (excluding crystal earpiece and key). although this could be reduced to 12 if a suitable single component inductor/capacitor with link winding was substituted for the only tuned circuit. The receiver is working and I copied an SV station and K1TG on 28MHz just now. The TX still chirps though. Now I am looking for some further 2-way QSOs (3 so far with best DX IT9QAU/QRP at 1414kms).

31 Oct 2011

500kHz WSPR

Yesterday I fired up the 500kHz WSPR kit (2mW ERP from the loop antenna) for the first time in several months and was pleased with the reports and level of activity. Several people joined in the fun and some new stations are now monitoring and reporting on the band. I want to get my 137kHz WSPR kit sorted this week with around 25W RF and maybe 0.5mW ERP if I am lucky.

29 Oct 2011

Sunspots update

As the days go by this autumn, the sunspot numbers continue to climb progressively and I am beginning to think we may be in for a decent cycle 24 peak after all. Certainly HF conditions have been excellent recently with MUFs up to 40MHz at times.  28MHz has been as good as I ever remember it in the last few weeks.

Have there been any recent revisions of the sunspot predictions for the next 12-24 months? If so, I would expect these to be upwards.

CQWW: update on 10m operation

After a few hours of intermittent QRP operation I've plenty of QSOs in the log, many when using just 500mW pep into my halo antenna. Stations have been worked with QRP in 5 continents on 28MHz SSB already. The band is almost filled with stations in a way that I've not heard since the last sunspot peak. If you want to work some QRP SSB DX on the HF bands, especially on 10m, then this weekend is your opportunity.

28 Oct 2011

CQWW SSB Contest this weekend

This weekend it is the BIG contest of the year - the CQ Worldwide DX contest (SSB) which runs all of Saturday and Sunday. Unless the sun plays nasty tricks, all the HF bands will be absolutely humming with SSB activity and for 48 hours the bandplans will be thrown into chaos as SSB stations spread out to find space.  I am not a great contest fan, but I do enjoy this one and, almost without fail, manage to work loads of US states on the higher HF bands despite running 5W pep or less. This year on 28MHz there is a good chance of working some USA stations with 100mW pep or less, especially later in the contest.  Last year I was unable to take part as we were away. This year I have told my wife that I am not available for anything else.


27 Oct 2011

IC703, K1 and MFJ Cub (15m) possible sale

The above QRP rigs, all of which are in good condition, are part of my station but very underused compared with the FT817 and my homemade gear. So, I am thinking about selling these and at a fair price. The 5W K1 has the 40,30,20 and 15m band module as well as the auto-ATU internally. The IC703 covers 160-6m at up to 10W. The Cub is 1W on 15m.

My question is what IS a fair market price to charge for each? Please note these are NOT yet for sale and I am only trying to judge what sort of price to charge if I do decide to do so.

XBM10-2 Micro-transceiver boxed

This afternoon I rebuilt the XBM10-2 28MHz micro-transceiver onto a small piece of copper laminate and put the whole transceiver in a small diecast box. The transceiver still chirps far too much, but it is in a state where more DX contacts will be possible and I can't see an easy way of reducing the chirp without making it more complex. Maybe I should call it the Chirpy-10?  I'm particularly pleased that the TX-RX offset is just perfect for operation on 28.060MHz CW.

I have just realised that by replacing the earpiece with my PC soundcard I can use several SDR packages to allow me to look either side of the QRP calling frequency. This rather defeats the simplicity though!

25 Oct 2011

Getting the shack back

Tomorrow evening my house grows about 200% in size. Actually my 2 delightful young grandchildren and their mums and dads go home meaning I can restore the shack to its main use! At the moment it is a bedroom for the two grandchildren, so amateur operation is impossible. One thing on the agenda is the CQWW SSB contest at the weekend. This is one of the contests I enjoy as it is a good way to work lots of US states and Canadian provinces, even with 5W QRP. Another task is to further optimise the XBM10-2 tiny transceiver, put it in a tiny case and work some more countries with it.

20 Oct 2011

2 countries worked with the 28MHz XBM10-2

Well, off to a good start today with a couple of QSOs with the 2 transistor XBM10-2 60mW 10m CW transceiver. Much to my surprise I got 439 from IT9QAU/QRP at 1547z today.  Distance was 1414km.

Then 599 (with chirp) from M0DRK, who is in the same village as me. So 2 DXCC countries worked already.  On receive, the oscillator will not always start in the latest circuit version in which I've reduced the component count by a further 2 parts (just 11 parts plus crystal and earpiece now).  Still, a very promising start for something so ultra-simple.

UPDATE 1850z 20.11.10: To get the oscillator to always start on RX, to get TX spot-on 28.060 with the right offset for RX I had to revert to the earlier design and put 2 parts back. The revised schematic is shown here. This IS such fun.

19 Oct 2011

2 transistor transceiver for 28MHz CW

This afternoon I built what is probably just about the simplest CW transceiver possible for use on 10m. Based on my XBM80-2 design for 80m, this is essentially the same circuit redone for a 28.060MHz fundamental crystal.

Depending on how much chirp one is prepared to accept (there is quite a bit) the power output is around 50-70mW, which is enough to cross the Atlantic on a good day. With less output the chirp should be reduced. The receiver audio output into the high impedance crystal earpiece is low, but I can hear down to around 2uV (-100dBm) in a quiet room. The circuit is a colpitts oscillator used as a TX oscillator with the key down and as a direct conversion receiver with a single stage oscillator-mixer and separate audio gain stage with the key up.

The rig is full break-in going from RX to TX when the key is pressed. It works as I have already heard Ws on the band today. Broadcast breakthrough does not seem to be an issue. I hope to have a few local QSOs soon, but really believe it will get much further.  It could do with tidying up and boxing and it really needs a small low pass filter for serious use.

18 Oct 2011

More WSPR database issues today

28MHz WSPR this afternoon - loads of signals
Sadly this afternoon the internet WSPR database crashed again, just at a time when 10m propagation was excellent and some decent reports were coming in from the USA and elsewhere with my 50mW to the halo. All afternoon I was getting an endless string of DX stations coming through on WSPR all running 5W or much less but I have been unable to upload these to the database or get my own reports from it. I noticed G4KPX about 15km away from me was testing on 10m WSPR with 5mW and I am sure he would have been getting plenty of DX reports in today's conditions. Let's hope the database is back soon so I can upload spots manually and see what reports I was getting in the last few hours.


17 Oct 2011

My other blog: Miscellaneous Musings

There are times when I want to speak my mind or share thoughts on matters unrelated to amateur radio. Rather than post these here in future, except in exceptional circumstances, I've started a new blog called Miscellaneous Musings which will cover all manner of subjects. Feel free to follow me there too and make comments.

http://qss2.blogspot.com

16 Oct 2011

10m AM DX QSO today

Today I had a nice solid AM QSO across the Atlantic to K2WF in Long Island on 29.010MHz when I was running just 4W to the halo antenna. My report was 55 and I gave Alan 57. He was running 25W carrier. This is my first 10m DX AM QSO in about 10 years and very welcome too.

Nostaglia - listen again to famous shortwave interval signals

If, like me, your first experience of short-wave radio was listening to DX broadcast stations back in the 1950s or 1960s on a simple home built radio you may want to take a nostalgic listen to the recordings of a large number of the interval signals from those far-off days. Even now, those evocative tunes send a shiver of excitement down my spine.  Some browsers may not like the link which is to my public Dropbox folder, but I assure you it is safe.

Superb HF conditions - sunspot count is high

Yet again, 28MHz is buzzing with signals right across the whole band with stations simultaneously coming through from the Far East and the USA. The sunspot number today is 166 which is very high. If the sunspot count and flux levels remain at this level or increase further in the next 12 months I think it is highly likely the peak will be a pretty good one, despite many predicting this would be a weak peak.

What I am hoping for now are some 6m transatlantic openings this winter. I well recall previous good peaks when 50-50.2MHz was filled with Ws and VE stations booming in at 59 on just a small wire dipole.

The Voice of the Common Man/Woman

This picture appeared on my Facebook pages today. It shows someone on one of the marches across the world protesting at bankers and the mess they have caused.  I think it is excellent and speaks volumes about the concerns of good, decent and ordinary people. Stupid bankers have gambled away OUR pensions and OUR livelihoods for the sake of THEIR short-term gain. Power to the people!!

15 Oct 2011

29MHz AM Signals

For the first time in several years I am hearing 10m AM signals coming through from across the Atlantic between 29 - 29.1MHz. Good signals from N1GKX and KA1CU amongst several others including UA and G. For me, 10m AM is like a time warp, reminding me of how the HF bands used to sound in my youth back in the early 1960s. Yet to work any DX AM this season.

12 Oct 2011

Wonder why the economy is in a mess?

"Virtually all U.S. senators, and most of the representatives in the House, are members of the top 1 percent when they arrive, are kept in office by money from the top 1 percent, and know that if they serve the top 1 percent well they will be rewarded by the top 1 percent when they leave office. By and large, the key executive-branch policymakers on trade and economic policy also come from the top 1 percent."

This is a quote from a recent article in Vanity Fair.

A similar situation exists here in the UK. In my view this is a situation which cannot be sustained and we need to wake up and do something about it.

6 Oct 2011

A VHF/UHF DX mode waiting to be discovered?

There is some indication that the long Europe to Japan path on 50MHz in the summer months is due to Polar Mesospheric Summer Echoes, or PMSE for short. Echoes of 224MHz radar in Norway suggest strong reflections, so I wonder why more radio amateurs are not trying for 2m DX using these mesospheric clouds?

See http://www.eiscat.se/raw/pmse.html. It is very likely these clouds and noctilucent clouds are the same phenomenon.

More success on 28.060MHz QRP

In the last few days I've been putting out more CQ calls on the 10m CW QRP frequency. This tactic is working as I've managed several decent QRP-QRP QSOs across the Atlantic including 8P6BX,  W3PO,  K1YAN and N0UR. HF conditions are certainly very good of late and 10m is back to its old ways when a few watts are all that is needed.

Steve Jobs - RIP

Today is a sad day for the electronics and computing world with the death of Steve Jobs of Apple. Not too many years ago Apple looked like simply fading into obscurity. Then Jobs came back and turned it all around. All my family have Apple products - PCs, iPads and, in my case an iPod Touch 4g. All work perfectly and are a credit to an innovative and creative company led by people with inspiration and vision. We need a few more people like this in the UK rather than giving credit to idiots in the banking and "investment" world who simply gamble our pensions and reap huge bonuses as a result.

RIP Steve.

5 Oct 2011

Crossing the Atlantic again with Sputnik TX

My CQ call today on 21.060MHz (using G6ALB's 400mW Sputnik valve TX) resulted in a reply from Jim W1PID who was 549 initially but he faded out before I copied my report.

2 Oct 2011

Sputnik valve TXs on air this week

All being well, for a few days starting October 4th I shall be on 21.060kHz using G6ALB's "Sputnik" valve TX which puts out 400mW. Several other stations around the world will be running similar rigs and with luck we will manage a few Sputnik-Sputnik QSOs. DL2BQD will certainly be on and also, with luck, some transatlantic propagation will be possible.

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."