More Sixboxes and Fredboxes

Joe Milbourn has a nice photo of his version of my Sixbox QRP 6m AM transceiver. It looks he's made some changes including the addition of a beefier audio stage on receive, perhaps to drive a loudspeaker.  It also looks like he has added a mic pre-amp. Click the link for Joe's original size image. Incidentally, there are some great photos on Joe's picture site.

Then I noticed a version of my 2m AM Fredbox on a Romanian website. See http://www.garajuluimike.ro/electrice/emitator-receptor-144mhz.htm . This version also uses an LM386 audio amp to drive a loudspeaker.

Latest Solar Data

Jan Alvastad's excellent page on solar data shows that for the last couple of months the trend in solar activity is downwards, not upwards. Now it is not uncommon for solar cycles to show more than one peak, with the second being greater than the first, but I hope that was not "it" and that we are now sliding down to the next minimum already! The image below is on Jan's site and I hope he does not mind me linking it here.

More on the German "Chirpy"

Today I got this email from Martin about his build of Chirpy:

Hi Roger,
Somehow the text of my email got lost when I send it from my phone. I like your blog very much, especially your homebrew projects. Yesterday I took the time to get the chirpy from the breadboard into a nic enclosure. I have plenty of this tins since my xyl likes to eat some paste that comes in them. My rebuild of chirpy puts out 210 mW and has a lot of chirp. Perhaps we can have a chirpy qso when the band is open.

Thank you very much for the design and your nice blog.
73 de Martin, DL8MAR

Slight progress towards a new 500kHz band

The latest reports from WRC2012 about a possible new allocation just below 500kHz sound slightly more hopeful than a few days ago with China and Russia softening their positions, but unfortunately the Arab group seems dead set against an allocation at all.  We'll have to wait until Working Group 4C (next level up) discusses it.  In the meantime let's keep our fingers crossed.

VLF Talk - Cambridge Club Feb 10th

On Feb 10th I have been invited to talk to the Cambridge and District Amateur Radio Club on VLF through the ground although I intend to widen the scope to include all aspects of amateur radio communications experiments below 9kHz. In the last year or so this aspect of our hobby has come on leaps and bounds and what was once thought of as impossible being achieved. Surprisingly, this is a very accessible part of the spectrum in which to experiment. If you want to come along and are not a CDARC member I am sure you'd be made welcome by club members.

Another 10m Chirpy

Martin Spreemann (callsign not known) in Berlin has sent me a picture of his version of Chirpy, the minimal component transceiver for 28MHz CW. I wonder what results people who have made this (rather chirpy) transceiver have obtained? Please let me know if you have built and used one. Remember the design uses a fundamental crystal for 28MHz, not a 3rd overtone. The design should work equally well on 24MHz (slightly less chirp too) and 21MHz, although I suspect broadcast breakthough will start to become more of an issue.

Optical "tree bounce" tests

Spectran screenshot of 481THz "treebounce" test 30.1.12

Last night I made my first recordings of my optical beacon in action. In one room of the house the 100mm optics beacon was set running QRSS3 and aiming at a tree 150m away across a field. This was a deciduous tree with just bare branches. In another room of the house, optically well isolated from the TX, I set up the 100mm optics KE7OEI head feeding an earpiece and my PC running Spectran. The signal scattering off the tree (total path length 0.3km) was 30dB over noise in a 2.7Hz bandwidth. This suggests (I think) that other non line-of-sight paths with a total distance of up to 1km might be possible by reflection off trees, buildings etc. I have still to try a true line-of-sight path at any distance with my current system but it will certainly be good for many kilometres.

Yesterday my 1W ultra-bright LEDs arrived from Hong Kong. When fitted to the beacon these will be VERY bright and will extend the range possible on 481THz yet further. All good fun!

A Czech Chirpy from OK1CDJ

Ondra OK1CDJ kindly sent me some photos of his version of my 10m chirpy transceiver. Currently he is getting around 50mW out, a little lower than on samples made here. I have suggested some things to check and possibly change. I really must find a way of making it chirp less, HI.

See http://translate.google.com/translate?client=tmpg&hl=en&u=http%3A%2F%2Fblog.ok1cdj.com%2F&langpair=cs|en for an English translation of Ondra's blog.

Optical CW beacon TX now ready

Today I completed my first keyed optical beacon transmitter (with 100mm optics) which I'll be using for tests at greater range than hitherto. The 481THz (red light) beacon sends my callsign in either 10wpm CW, QRSS30 or QRSS60 as well as a continuous carrier or a 30sec on/off sequence. The TX uses a sub-carrier of 1.082kHz or 8.659kHz, the frequency being derived from an HF crystal divided down in a 4060. The message comes from a K1EL K-ID2 programmed PIC. Initial tests this afternoon at dusk allowed me to copy the 1.082kHz 10wpm CW sub-carrier signal by reflection off a wall across the street at decent strength.

My next challenges are to find some local paths of a few kilometres to check the beacon and the receiver. I'd also like to try some non line-of-sight paths, possibly including cloud-bounce.

How sensitive can headphones be?

Having made several short-wave crystal sets in my time I have nearly always used the little "deaf aid" very high impedance crystal earpieces as the acoustic transducer. I thought these were very sensitive being able to copy HF AM signals down to around -55dBm to -60dBm. However I recently read somewhere that with the old WW2 DLR5 low impedance headsets one could hear an applied audio signal as low as 2uV (-101dBm), which is remarkably low.  

So, I began to wonder just what ARE the best headsets to use if one is after the maximum efficiency converting an audio frequency electrical signal into sound pressure in the ear?

This graph (from Wikipedia) shows the sensitivitity of typical humans at different ages. Someone of my age (63) is likely to be less able to hear as low as someone aged 30 years.

As some of these old military surplus headphones can be hard to find nowadays in good condition, I wonder what is the most sensitive headset/earpiece that can be bought new "off the shelf". Any ideas please?

Dropbox Problem

When my grabber is running I use Dropbox to automatically upload the captured image to a location on the net where anyone can see the image. Recently Dropbox has been doing something wrong and when I try to launch the program I get an error message (see image). I have tried EVERYTHING to fix this, to no avail so far. Has anyone else had this issue? I looked on the Dropbox website (not too helpful), tried running Ccleaner to see if the registry entries were faulty (no luck), reinstalled the software (about 10 times now in different release versions) and deleted each when the same darn message appeared.

Help!

New beacon chips arrive

Today my new KID2 pre-programmed beacon ICs arrived from www.k1el.com . These are for use in my VLF, 136kHz, 500kHz and 481THz beacons. With 7 pre-programmed messages in 10wpm CW, and various QRSS speeds these are ideal. I have used these before and been very satisfied.  See http://k1el.tripod.com/files/kid2man.pdf for more details of the ICs.

Laptop/Netbook Reliability

Investing in a new laptop or netbook can be a tricky decision: getting the right price, spec, performance and reliability. My Dell laptop failed a year or so ago (keyboard) but I was able to repair it by buying a new keyboard via eBay and following some good fitting instructions found on YouTube.  My wife's school laptop LCD screen just failed suddenly when it was in use on her lap with black "cracks" appearing as if the whole thing had been dropped. This was repaired under warranty thankfully. Then you hear of hard-drives failing.

Today I came across an interesting page giving some reliability statistics for laptops and netbooks. Apparently Asus and Toshiba make the most reliable ones. The paper is by a company selling extended warranties, so they will be keen to show that it is worth buying one. Nonetheless I think the stats are fair.

FT-450D hum: a good response from Yaesu

Last night I wrote to Yaesu UK about the FT-450D hum issue and got a very fast and very helpful, response from Paul Bigwood their Technical Sales Manager. All credit to him.

I will paraphrase Paul's reply below.

He confirms the hum problem has been recognised and that it doesn't affect all radios. Those it does, are only affected in voice modes, when the display brightness is reduced below its normal maximum level. The level of hum is generally low and is usually only noticeable when the received signal strength is high [i.e. with local stations], DX stations don't normally hear it.  He says that steps have been taken to resolve the issue and product shipping into the UK dealers since the beginning of the year have a modification to resolve it. He told me that if I purchased one that does suffer from hum under the circumstances as above, then it can be returned to Yaesu for updating under warranty.

He went on to say,

"Please rest assured that Yaesu does care about its products, their reliability and performance. We certainly look to resolve any problems as soon as they become known to us.  The FT450D is a splendid radio, having done excellently at the T32C DXpedition last year when over 200K QSOs were made with no reports to us of any hum problems."

I thought this was an excellent and totally professional response. Yaesu is a first class manufacturer and it is reassuring to see they have taken on board the hum issue in this otherwise excellent little radio and have now taken steps to properly fix it on new build units.

137kHz transverter bites the dust

Having re-erected my 80m loop antenna I was about to reload OPERA and give it a try now it appears more stable. I ran up the transverter on WSPR to check all was well only to have the power supply suddenly take around 20A and shut itself down.  I think the MOSFET PA died on me. All being well I will get this fixed next week when my grandson goes back home again and have another try.

Netbooks

For many years I used a little Asus EEE PC701 (7 inch screen) netbook running a pre-loaded Linux OS. This was ideal for basic net surfing and emails, but it lacked the flexibility of a Windows OS when looking for ham radio software. At the moment I am looking at a possible replacement that I can use for general web browsing and also to run WSPR, OPERA and hopefully Spectran and Spectrum Lab freeing up the main PC. Such a small netbook would also be useful for field use with VLF tests, lightbeam experiments etc.

It is quite amazing what £200-250 will buy today. My first laptop cost me £1499 back in 1998 and the performance was nowhere near that of even my little Asus EE PC701!

My inclination is to buy another Asus machine unless someone can give me good reasons to choose another make.

A new meteor scatter mode

http://www.dk5ew.de/2012/01/13/psk2k-a-new-meteorscatter-mode-by-dj5hg/

This webpage gives details of an interesting high speed MS mode from DK5EW. There is also a Yahoo group to discuss this: see http://uk.groups.yahoo.com/group/psk2k/

"PSK2k is high speed meteor scatter software written by Klaus DJ5HG (Prof. of Computer Science at University Hamburg).  It allows 2 way MS QSO’s to be conducted with any suitable transceiver/PC/soundcard combination.

PSK2k is fully error correcting and call specific in operation so you will only see the QSO in progress and any non-QSO CQ or QST text. All other transmissions (other people also in QSO) are discarded. This allows multiple QSO’s to take place on a single frequency.

PSK2k can be operated in fully automatic mode if required. This enables QSO’s to be completed fully automatically without user intervention. Important advantages are that long term testing can be done, on QRP power for instance, without having to sit an monitor every period."

Philips FM321 70cm mobile

The very first FM synthesised 70cm rig in the UK was made by Philips in Australia and was called the FM321. This 4W mobile was based on the very similar FM320 designed for the Australian UHF CB band. I owned an FM321 for a couple of years back in the early 1980s and really enjoyed using it on the UHF simplex channels and repeaters. Ergonomically it was excellent with simple up-down channel change and a decent volume control. It is a pity rigs are not made as simple as this today. No memories, no fuss.

From the home QTH and with just a hand rotated small vertical yagi I could work some impressive DX on FM on some days. That's the thing about 70cms: propagation changes within hours and often in very localised directions. When there was plenty of simplex activity it was very interesting watching propagation change and the maximum range change from maybe 30 miles to over 100.

WRC-12 Radio Conference (Jan 23 - Feb 17)

This most important international frequency revision conference takes place Jan 23th - Feb 17th. As always, the amateur service can never be certain of the outcome with a possibility of precious spectrum being lost to other services. However, this time there is a good chance that we will GAIN a new amateur MF band somewhere between  415 and 526.5kHz. The most likely outcome is a band near 480kHz around 8kHz wide. 8kHz of spectrum would allow much more experimentation, especially if this allocation was world-wide. This would supersede the special permits around 500kHz allocated in some countries.

Nice antenna for 80m QRP?

This is most definitely NOT my idea of amateur radio, but you can't fail to be impressed at the dedication of this Russian amateur to put out a big signal on 3.5MHz. This is a full sized 3 element yagi for 80m, meaning the driven element must be about 40m long.

Optical RX improvements

G8CYW Optical head (April 2011 RadCom)

I've now bought some NE5534 low noise op-amps so can implement the full G8CYW optical head circuit which many users have successfully adopted. Stuart describes this as "exquisitely sensitive". I have BPW34 PIN diodes but think the sensitivity should be similar to that with the SFH2030 diodes used in Stuart's design.

In the first instance I need to remeasure the noise floor with the optical head in total darkness to see if the changes indeed make it better than the current discrete component circuit.  My first quantitative noise measurements suggest far higher noise floor than I expected.

Assuming this gives improved performance over my 0.4km local "up the road" test range, my next step is to attempt a longer path, so I am looking for a path of around 2-3km to test with my baseband beacon. If this works with decent S/N then I'll retry looking for the GB3CAM optical beacon. At 32km this is a good test of system performance. At the test site at Nine Mile Hill the traffic noise was high (optically and audibly) so I also need to increase the signal level in the earpiece used to align the RX.

There is also soon to be a second optical beacon near Cambridge and this should be a little closer and an easier signal to find. However, I need to do tests before this is installed at Dry Drayton.

Incidentally, I managed to overcome the parallax issue in the optics alignment  so now a distant street light is spot on in the cross-hairs of the spotting scope.

FT-450D Hum (again)

From what I see and hear, Yaesu is still selling this otherwise excellent HF/6m transceiver with a fundamental design flaw: hum created by poor grounding of the display module when dimmed from maximum brightness. This problem was there on the FT450 but whatever improvement, if any, was implemented in the upgrade to the D version,  it has not worked consistently.  This really annoys me: surely this sort of issue should have been picked up in beta testing? The fix being implemented by many owners seems simple, so why the heck doesn't Yaesu get on a fix it?

OPERA (weak signal mode) - a word of warning

Since installing Opera V1.0.4 a few days ago my Inspiron 630m Win XP PC has started to behave very oddly. For years it has worked in a very stable fashion with very few issues in 6 years of use.  Now it is slow (very slow) even when not using OPERA, CPU load is high and running Ccleaner, which usually takes a minute, took nearly AN HOUR to get rid of 156M of files to be cleaned up.  Now, I cannot PROVE the link, but the coincidence is remarkable.

To make matters worse, the software once installed does not appear to be listed in the list to uninstall. Not being a PC expert I am loath to just remove all the obvious files in case this damn program has left something behind that "leaves its mark".

The lesson is DO NOT INSTALL DODGY, UNSTABLE AND POORLY WRITTEN SOFTWARE unless you know what you are doing and you know how to get rid of it safely and completely.

OPERA, as a weak signal mode is interesting, but I am VERY unhappy that it has messed up my good old faithful PC.

SAQ VLF 17.2kHz test 10.1.12

The historic Grimeton VLF transmission over Christmas on 17.2kHz had to be abandoned because of an equipment failure but Lars (SM6NM) says they are planning another test tomorrow (Tuesday Jan 10th) at 1330UTC.  The sequence will be "VVV VVV VVV DE SAQ SAQ SAQ" running for about 30 minutes and no message. No QSL cards will be issued this time. More details see www.alexander.n.se.  One possible receiver to use is SM6LKM's simple VLF SDR that can be downloaded from http://sites.google.com/site/sm6lkm/saqrx .

This was what they said about the Christmas failure:
 
"The reason for the trouble with SAQ on Christmas Eve was most probably a damaged fuse in the excitation circuit for the 500 V DC generator. The fuse was not completely blown but measured a very high resistance (150 ohm). When we lost the excitation current to the DC generator, we also lost the control current to the choke coils in the conductors to the main motor, and thereby the speed control of the alternator was lost.  It was confusing that the problem occurred exactly when we connected the running alternator to the antenna. We were actually on air a few seconds with decreasing frequency until the antenna was disconnected by the protection circuit in the speed control."

Optical setback (of sorts)

RX set-up at Nine Mile Hill on 481THz tonight

Flushed with my local successes (0.4km) last night, I decided to have a go at looking for the GB3CAM optical beacon 32km away from a local high spot where I know others have copied it sending its 1/15kHz FSK sub-carrier data at 481THz (red light). I set up in the daylight so I knew where to aim approximately and had the PC ready with SAQ receiver (0-22kHz SDR) and Spectran all ready. After dark I started to seriously hunt for the elusive signal    .....but with no success.

Failure can be put down to several possible causes:

1. Difficulty in aiming. Although I knew where to aim, I am uncertain that my spotting scope is correctly aligned on the 100mm optical head and that there is no parallax error. Looking for a very weak signal is therefore hard to start with.
2. Inadequate sensitivity in the optical head. Although I could hear the 50Hz buzz from every street light and house light locally, maybe there is another 6-12dB to be had in basic sensitivity in the optical head.
3. Inadequate volume on the recovered baseband audio. I was monitoring the "live" feed with just a crystal earpiece attached to the head and, although this is fine at home and down a quiet street, it was too low a level to hear weak signals over the traffic noise from the main road which adjoined the field gateway at the RX location.
4. Path loss. According to G4HJW, the beacon keeper, the signal varies from 5-30dB over noise at this location, assuming one is aligned correctly. Although the weather was cloudy and good visibility there was drizzle that came in as I was testing.
5. QRM from car headlights. As cars came along the main road near the test site, I got quite bad buzz from their headlights.

So, not to be beaten, I will do things to address all these problems and try again quite soon. I think I need a better local test beacon that I can use to (a) check aim, check RX sensitivity and adequacy of the recovered audio.

Quantitative tests with 481THz kit

Today, in daylight again, I did a repeat of my recent tests with the baseband pre-focused red LED TX (20mA), looking for the signal 0.2km along the road. This time I also took my PC and looked for the signal with Spectran and the SAQ SDR receiver. The audio tone was around 40-50dB over noise on both systems.  At this range I would have expected far better S/N. The noise floor looks high. When I blocked off the lens the noise floor went UP about 15dB. Why I wonder?  The picture shows the test set-up. If you click on the image you can see the pre-focused red LED pointing out of the house window and the receiving kit in the bottom foreground. Based on these results speech communication, even with just the same LED and no external lens on TX, should be possible to at least 5km. With 100mm lenses at the TX end, considerably further should be possible.  Below are the test results.

UPDATE: After dark I repeated the range test, just using the crystal earpiece to listen to the signal detected by the PIN diode head. At 0.4km, the greatest distance I could go line-of-sight from my home QTH, the audible signal was STRONG, which is very encouraging.

See my website https://sites.google.com/site/g3xbmqrp/Home/opticalcomms for more details and links.

OPERA - new weak signal beaconing mode

There is a new very weak signal beaconing mode being trialled currently on 136 and 500kHz called OPERA. The current version is available as a zip download at http://www.mediafire.com/?w74a061m48nv806 but this is a beta version and updates are happening quite fast at the moment, so best check the RSGB's LF reflector for the most recent version from Graham G4WGT.

Initial indications are this is even better than WSPR, which as we all know is an excellent QRP beaconing mode. I managed to decode SM6BHZ (just under 1000km) and PA0A tonight when using just my 20m separated earth electrodes (no antenna in the air here at all) on 136kHz.

Over the weekend I may give this a go with a few mW ERP on 500kHz and, when I get my vertical loop re-erected, on 136kHz too.

Early days yet, but a most interesting mode that does NOT need critical PC timing (unlike WSPR) and that can use the PTT line or VOX control to key the TX i.e. it is simple to interface rig to PC.

Optical receiver head completed

481THz optical receiver with 100mm lens

I now have a 100mm lens set-up in some grey drainpipe with 4x sighting scope attached on a tripod together with a "simplified version 3" KA7OEI head (of sorts) with a BPW34 detector. In my version the cascode stage is just followed by a single common emitter stage driving a crystal earpiece, although I intend to add an emitter follower so I can connect to my PC (to use with Spectran/SDR) or a transverter.

A 5mm 20 degree red LEDusing just its own built-in lens was shone out of the stairway window aiming down the street in daylight with 1kHz modulation. It was taking around 20mA. I then walked with the kit to the far end of the street and the signal was solid (S9) in the RX earpiece at a distance of about 0.25km. I now need to find a more distant test range and see how far this can achieve. Depending on results I hope to go looking for GB3CAM next week.

Lightbeam receiver progress

Today I did the part of projects I hate most - drilling holes in aluminum boxes. I can never find the right size drill bits, they are blunt and so on. Despite all this, I managed to get a small metal box complete with BNC socket, phone jack and switch mounted on the end of my optics pipe and carried out some first tentative tests. I am using part of a simplified version 3 KA7OEI optical head based around a BPW34 PIN photo diode. In my case there are no op-amps with discrete transistors used for the amplifiers and buffers following the FET cascode stage.

In the next day or so I want to add the sighting scope and find a way of attaching the whole optical unit onto a stable tripod. At this point and can try some more serious tests for example looking for my own 1kHz beacon at greater distance and, hopefully, GB3CAM at 22km if the system works OK.

The output of the head can feed either a crystal earpiece (to listen to the baseband tones or speech received) or into a PC so that it can be used with an SDR to copy various modes up to around 22kHz.

Winter project list

In this first post of 2012 I thought I'd list the projects that are "on the to-do list" for the coming few months. As always, this is subject to change without notice as my interest and enthusiasm goes through waves:

1. Lightbeam RX. The aim is to detect the GB3CAM 481THz optical beacon at a distance of 22km from my nearest highspot. So far I have breadboarded several good sensitivity optical detector heads and the next stage is to complete the packaging of this into a screened box and attach it to my optics which also need a bit of engineering to complete. Target is this to be completed next week.
2. Light beam transceiver. Following on from (1), this will either be a transceive head with a transverter or an FM transceiver that I can duplicate so I can talk to others who can borrow the second unit.
3. Rebuilt VLF earth mode beacon transmitter. In a few weeks time I will be able to put out a stable signal on 8.97kHz  (the usual VLF test frequency) rather than 8.76kHz. My intention is to rebuild the whole beacon TX so I can run 10wpm CW, QRSS3, 30 and 60 modes as well as WSPR. I may also add a 100W PA option later. With this kit I hope to improve my personal earth mode DX record of 6km.
4. Improved LF loop and E-field probe antennas. I want to erect a more permanent external antenna for VLF and LF grabber work and mount these away from the house. Up to now I have used my 80m square vertical loop on RX but this is currently down.
5. Case up the 137kHz transverter. This has been a rat's nest on a piece of copper laminate for too long!
6. 28MHz WSPR transceiver based on a 14.060MHz crystal doubled in a DSB direct conversion transceiver circuit.

Now, how many of these projects get done is a matter of conjecture, but I hope at least 50% of them will get finished.

Happy New Year

A very happy New Year to all readers of this blog.

2012 should bring us even better HF conditions as we approach the peak of Cycle 24. With luck and hard work we may get a new MF band around 480kHz. As ever, there are challenges from VLF to light beams to be enjoyed and I hope you have as much fun with our hobby as I shall.

My priority once the Christmas holiday is over is to complete my 481THz lightbeam transceivers and test these locally. Further projects will be to improve my VLF earth mode DX and to set up a lower noise VLF grabber in anticipation of more activity in the months ahead. In addition I shall continue with QRP WSPR and QRP operation mainly on 10m and 6m.

Netherlands on 500kHz and 70MHz

Some good news: amateurs in The Netherlands now have access to the 500kHz band (again) and 70-70.5MHz (4m).  Countries permitting 4m operation are growing every few months. Let's hope one of the major equipment manufacturers includes the band in multimode HF-6m rigs. Adding 4m cannot be too hard.

Elecraft KX3 can now be ordered

On Dec 27th 2011 Elecraft announced that their new QRP radio can now be ordered with deliveries starting in about 8-9 weeks time. As a QRP radio the KX3 is likely to be "best in class" with some excellent features, but it is not low cost when loaded with options and imported into the UK after VAT and any duty is paid. See the KX3 page for more details.

The basic KX3 includes:

   * 10 watts output typical (13.8V) on 160-6 meters. (Up to 5W using internal batteries)
   * All modes (SSB, CW, Data, FM, AM)
   * Many features from the Elecraft K3, including the same full-size LCD
   * Advanced DSP features, including PSK31 and RTTY text display, noise reduction, auto-notch
   * Built-in 8-AA-cell battery holder
   * USB serial cable for firmware upgrades and for use with logging/contesting software

Available options include:

   * KXPD3 precision attached keyer paddle
   * KXFL3 dual-bandwidth roofing filter module for SSB/CW/Data modes
   * KXAT3 internal wide-range automatic antenna tuner
   * KXBC3 internal NiMH battery charger
   * MH3 hand mic with UP/DN VFO controls
   * RS232 control cable (optional replacement for supplied USB cable)

Although I certainly covet this little radio, I have not decided if I can justify the purchase, or indeed afford it!

Happy Christmas

To everyone that reads this blog from time to time, may I wish you and your friends and families a very happy and peaceful Christmas. It is a time to both give and receive love and kindness - enjoy it.

Shortwave broadcast QSLs

Talking about QSL cards makes me think of my very first QSL cards received back in the 1960s. In those days I used the ISWL QSL bureau which handled broadcast band QSLs (I think it still does) and well remember the thrill when I got my very first cards. The first ever QSL was from Radio Nederland and it was an exciting moment. Somewhere I still have that red card with a windmill on!

In the subsequent years I did a fair bit of QSLing when using just my shortwave crystal set and got a few cards back from these reports. I heard stations all over the globe using that simple crystal set with best DX being Radio Havana Cuba, All India Radio and even Radio Australia, all direct and not via any relays. Not bad for just a tuned circuit, a diode a resistor and a crystal earpiece. I must have another go at a shortwave crystal set just for fun, especially as HF conditions are so good now, but these days shortwave broadcasting is not what it was. Using a decent toroid and a bridge detector it should be possible to arrive at a sensitive design with quite good selectivity.

WSPR QSL cards?

Just been having an interesting debate on Facebook about someone requesting an eQSL for an exchange of WSPR reports. Some would argue that, simply exchanging reports via the WSPR database does not constitute a "real" QSO, so a QSL is not appropriate. Indeed, some would say the WSPR database report is itself a confirmation of the report (which it is) so what is the point of a QSL card? On HF contests it is VERY common for only one callsign to be heard in reports such as, "G3XBM 599233 TU" yet such exchanges are used for DXCC credits if a QSL card is sent following such a "contact".

Personally I would eQSL a full 2-way exchange of WSPR data if done within, say 10 minutes, on any given band and consider this valid. I will only do this in response to one received. Others may violently disagree!

Quartz crystal suppliers in the UK

Recently I wanted to buy a couple of non-standard crystals for a VLF project with the crystal divided down using a 4060 divider. After asking other people for advice it looks like Quartslab can provide the service.  Individual crystals range from around £12-14 depending on frequency and type.

This is not cheap, but at least they can offer the low quantity service. There is a minimum order charge of £22.29,  so I will probably order a couple of crystals for 4.59264MHz to give me a stable signal on 8.970kHz when divided by 512.  The company contact is Dave Hayes G4AKY 020 7100 6357.

Ultra-simple WSPR

G3XIZ has been having a lot of success on 40m WSPR recently using a 100mW DSB transmitter to generate a WSPR signal. All that is needed is an audio source (for the baseband WSPR signal), a balanced mixer and a PA. Of course, with this arrangement 3dB of power is lost in the "other" sideband which will appear outside of the WSPR sub-band. At some point - when I've got my lightbeam kit finished in January - I hope to try this arrangement on 28MHz WSPR. A very inexpensive 14.060MHz QRP frequency crystal will double to 28.120-28.130MHz so will be ideal to generate a 28MHz DSB WSPR signal at 28.1246MHz. Of course one could convert the TX into a phasing exciter and null out the other unwanted sideband. This should not be too difficult either as the phasing has only got to be good over just a 200Hz wide audio band, unlike speech which needs good phase balance over the full 300-2.4kHz band.

15kW HF PA - definitely not for a QRP man!

A friend sent me this link http://www.dc9dz.de/en/index.html which shows the design and construction of a 15kW HF PA circuit for the amateur bands based around the Eimac 4CX10000D valve. Although I have no real interest in very high power and I do not expect to hear this on the air (please no!), it is a rather elegant piece of radio engineering.

EU bureacracy threat to ham radio kit building?

The excellent Southgate Amateur Radio News site has some information which should concern amateurs who build kits. They recommend writing to your local MEP to make you views known.

"Thilo DL9KCE, reports a threat to amateur radio kits and modified equipment arising from changes to the EMC directive.  Currently amateur radio kits and modified equipment are specifically excluded from the directive but under the proposed changes they would be fully subjected to the EMC directive. The resulting high compliance costs could make it uneconomic to develop and sell kits so killing off the kit market. If radio amateurs wished to modify equipment it appears they would also incur additional costs and bureaucratic hassle."

The aim of the EU as a common market for trade is sensible but, like many here in the UK, I abhor it when the bureaucrats in Brussels start to interfere and try to fix things that are not broken. I don't want to get into a debate here about the merits of the Euro, but do feel that 2012 will be a year in which the citizens of Europe, and that includes the UK, will face some very tough decisions.