GQRP SPRAT

Many times before I have mentioned how good SPRAT magazine is.

This comes out every quarter and is now in full colour A5 format.  Most of the back issues are available on a DVD and it is worth joining just for these. If you enjoy simple projects you will find lots to inspire you!

It is only a few pounds to join GQRP and the DVD is heavily discounted for members. Most editions have something simple to make.

Many of the founder members are now SK, but these have been replaced by keen, younger folk.

See http://www.gqrp.com/sprat.htm

GQRP Club

For very many years now I have been a member of the GQRP Club. This is an excellent organisation that produces a quarterly magazine called SPRAT. If push came to shove, this is the one magazine I should keep. Back issues of SPRAT are available on  a club DVD.  It is worth joining just for this as members get a discount. SPRAT is filled with simple projects to build and members' news. If you like QRP radio, you will enjoy SPRAT.

See http://www.gqrp.com/

GQRP Club and SPRAT magazine

Several times in the past I have said that, if all other magazines had to be cancelled I'd keep GQRP Club's SPRAT magazine. This small format magazine comes out quarterly and is excellent value for money. You don't get the endless adverts by the few remaining national radio companies in the UK, just a few adverts from companies selling bits.  Every quarter there are articles showing things to build or ideas on which to base your own projects.

SPRAT really is first class and all produced by unpaid volunteers who love our hobby. As much as I enjoy browsing PW and RadCom, I look forward to getting SPRAT far more.

See http://www.gqrp.com/ .

GQRP Club

See http://www.gqrp.com/ .

Many times before I have said that SPRAT is the last magazine I would give up if I had to. GQRP Club membership is very reasonable indeed and I highly commend it to you. They now sell a DVD which has the first 160 copies of SPRAT on it.   If you join the club,the DVD is very inexpensive plus you get the next 4 SPRATs with the subscription. SPRAT is always filled with good stuff and always plenty of projects to build.

Go on, join!

GQRP Club and SPRAT

I have many times said that if all radio magazines had to go, then GQRP Club's SPRAT would be the very last to go. This quarterly magazine is low in cost, very high in simple projects to build and the back page always has GQRP Club sales items.

Of ALL the magazines I see, SPRAT is without doubt the best. Back numbers of this excellent magazine are available on a DVD.

This is a little (sized) magazine but it is excellent value. The best in fact.

SPRAT on DVD - new version

I am a great supporter of the GQRP club. Their quarterly magazine SPRAT represents the very best in Amateur Radio. If you are interested in QRP then please join the GQRP Club. It is excellent.

There is now a new, up to date version of the DVD with all back copies of the excellent SPRAT magazine.  If I had to stop all subscriptions and magazines then the GQRP club (and SPRAT every quarter) would be the only one I'd keep  - it is that good.

Hi

Tony & I have been working away and we have produced the latest version of the Sprat-on-DVD. This includes all Sprats right up to the one that has just been sent to members (number 160).

It is now available to members at £5 plus £1.20 postage. I will have them at the Galashiels rally and at Rishworth of course. The local guys who represent us at some of the other rallies will also have some shortly.

As we have known that this issue has been on the way for a while, as a concession, we will let anyone who bought the current DVD (1 to 148) after 1st August this year, have a copy of the new DVD for the special price of £2.50 including postage. To get this deal, you have to tell me when you bought the old DVD – if at a rally, which rally it was, and send me the CD case paper label together with the £2.50 in stamps. I do not want the actual DVD, just an assurance that you will destroy it when you receive the new one.

I should add that this is for members only of course, and applies just to UK members! Overseas members who think they also qualify should contact me direct and we may be able to work out a deal for them also.

Overseas prices are on the club website - http://gqrp.com/sales.htm

The new DVD is available to non-members at £12 plus the appropriate postage.

Thanks

73

Graham

G3MFJ

Simple 28MHz Polyakov Mixer WSPR RX

As the first part of my WSPR transceiver project for 28MHz, I breadboarded a Polyakov harmonic mixer based, crystal controlled, direct conversion receiver this afternoon. It was a great success!

28MHz Polyakov mixer based WSPR RX

The circuit shows the idea implemented. A low cost GQRP club 14.060MHz crystal is pulled to 14.0623MHz in the oscillator/buffer stage. This is then injected into the back to back diode "Polyakov" harmonic mixer which switches at 2x injection frequency i.e. 28.1246MHz, the WSPR USB dial frequency. The 28MHz input from the antenna is filtered and directly applied (no RF amp) to the diode harmonic mixer with the audio output amplified and filtered in the 2 stages of audio gain. The output then goes to the PC sound card. I may improve the audio filtering and add a 600ohm line transformer between the audio output and the PC mic or line input.

Minimum discernable signal (MDS) is around -124dBm, possibly a shade better. AM rejection was tested by injecting a 100% AM modulated carrier at 28MHz. An input of -53dBm was needed before the AM signal was detected, so 70dB AM rejection, which I think is very good.

More bench work to do, then I'll try looking for 10m WSPR signals on-air with the RX, but for about an hour of work, a very fine result. Once the RX is air-test proven, the TX part will be added to make a complete WSPR transceiver.

GQRP Component Data Book

Tony Fishpool G4WIF, G4CCQ, G3OOU and others have created an on-line, downloadable, GQRP Data Book which has the pin-outs of a number of devices commonly used in QRP designs featured in SPRAT and elsewhere. It is just what I need to stop me having to look up parts on the internet every time. This is "a work in progress" as they say with updates and additions coming frequently.

Finally, why not join the GQRP Club? Its quarterly magazine SPRAT is still the best amateur magazine in the world and remarkable value at £6 UK, 12 euros or $18 US. Details at http://www.gqrp.com/join.htm .  As well as very interesting constructional projects, the magazine has operating news, useful adverts from QRP suppliers as well as adverts for GQRP club sales which supplies members with useful QRP parts (semiconductors, crystals, DVDs of SPRAT back issues, etc) at very reasonable prices. The GQRP club represents the spirit and ethos of amateur radio at its best.