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.

Waters and Stanton - wake up guys!

Today, having still received no feedback from Waters and Stanton about my emailed question on the FT-450D TX hum (has Yaesu fixed it yet?), I decided to ring them up, check prices and ask the question directly. To my amazement the sales person said, "I have never heard of the TX hum problem". Well, he can't be too well in touch with the market and customers then.

I also asked what was the best price for the rig ("same as in the magazines, no deals") and then asked if they still had the 3 year warranty running. "What 3 year warranty? I've never heard of that." I pointed him in the direction of several recent RadCom and Practical Wireless adverts.

In summary, I was NOT impressed with the responses, or rather lack of them, from this well known UK supplier. At a time when business near Christmas is tight surely it is important that sales staff  know about the product and can answer questions as simple as "what is the length of the warranty?".

Unless this supplier wakes up a bit I think I will defer my decision about purchasing the FT-450D.

Incidentally, they did say that Yaesu would be at Hockley this weekend for the W&S open day. I expect people going will ask about the TX hum question directly. And I wonder if there will be any news about the FT817's replacement?

Simple speech processing

Recently Peter Thornton G6NGR sent me a number of example circuits for speech processors, some dating back to the 1960s. Anyone who operates QRP SSB on HF or VHF will appreciate how important "punchy audio" is when running low power. One circuit I remember working extremely well was one based on an idea by John Hay G3TDZ. Back in the 1970s I was using 100mW AM on 2m and wanted to be heard across Cambridgeshire. My audio stage consisted of a couple of pre-emphasis stages followed by a hard audio clipper and a low pass active filter. The result was an amazingly punchy signal with barely any change in audio level when talking. The 12dB/octave pre-emphasis helped to ensure that clipping of LF signals did not result in many artifacts within the audio passband. The LPF was essential because the heavy clipping  results in many audio harmonics which would otherwise result in a broadened signal. With just 100mW and a dipole the QRP AM signal was excellent copy across the county. I keep meaning to try the same circuit (if I can remember it) with the FT817. It would produce a mighty punchy QRP signal!

KX3 release date

The Elecraft KX3 10W QRP transceiver is edging slowly towards formal release for orders. There is an enormous pent up demand for this 0.1- 10W QRP full featured HF/6m radio. Elecraft are still expecting to be able to announce that orders can be placed by the end of December with first products reaching customers in Feb 2012. I am still unsure if this is a possible candidate for my replacement to the IC703.