ARRL propagation forecasts

For those of you who subscribe to the ARRL (not everyone does and I have no plans to renew my subs next year),  the weekly propagation forecasts make interesting reading.  Even more interesting are the archived old forecasts, so we can see just how good conditions are compared, for example, with the same time in 2007.  As I mentioned before, if you are not an ARRL member you will not be able to follow the link, I believe.

ARRL members see http://www.arrlrg/w1aw-bulletins-archive/ARLP054/2007 .

Why am I not renewing my digital subscription with ARRL? 
Earlier in the year I could not use my password and it took a week to sort it out. The online help was no help at all. It took several emails before anyone actually helped me. Most of QST seems to be ads similar to those in UK magazines. I cannot see the value in continuing ARRL membership. In summary, the ARRL seemed a pretty useless organisation. I was NOT impressed.

GQRP Club membership is much better value in my view.

WISPY 10m WSPR beacon video

A few people have requested a video of WISPY, my QRP WSPR beacon for 28.1246MHz. This video shows the TX beacon only. I have a companion RX breadboard that works well and at some point these will be combined into a small 10m WSPR transceiver.

Delay getting 472-479kHz released in the UK?

On the GQRP Yahoo group today Colin, G8FRA/M5FRA, posted this message regarding the release of the new 472-479kHz band in the UK. If his information is correct, there could be some delay in the bulk of UK amateurs gaining access to the new MF band. This would be a great pity.

"Roger,

From what I learned by talking to a couple of people at Newark (RSGB and OFCOM) we will not get the new allocation in Jan 2013. Those with existing SRPs will have them changed to remove 500kHz and add 472-479kHz. I asked when applications would reopen and there was no date for that. Evidently OFCOM have to consult before there can be any changes to the license schedule and have been too busy with the Olympics to make any progress on that. I did suggest that the RSGB should come clean as anybody who has spent time and money on new equipment might just be a bit disappointed.

Colin - G8FRA/M5FRA
m5fra.org.uk"

If this information is correct, then why is our national society, the RSGB, not making this public? I have written to OFCOM and the RSGB asking for more concrete information.

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.

Universal QRP Projects Box?

This is really a follow-on from the previous post. As a "mechanically challenged" QRPer I really do hate the stage of putting a completed project into a tidy box. Some people love drilling holes but many do not, so I wonder if there is a market for a "universal" QRP projects box with pre-drilled holes at the front and back? Perhaps a variation of the GQRP Limerick project box could be made available for wider project use?

Most QRP transceivers need a power connector, a coax socket and a key on the back. They need a VFO(or VXO) control knob, a gain control and a socket for phones. Maybe another control and a couple of front panel switches.

So, I wonder why no-one (as far as I know) produces a pre-drilled box that could be used for a range of projects. Surely there is a market for this. A set of water transfer control legends could also be supplied with the box (remember the Radio Constructor sets?).

Just my thoughts having spent an afternoon engineering a 481THz transceiver mechanics and drilling an aluminium box.

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!

GQRP Limerick Sudden kit

The GQRP club (subs £6 per year - excellent value) is now selling the Limerick Sudden kit. This is an improved version of the classic Sudden direct conversion receiver for various single HF bands. The cost includes everything you need including battery , knobs and case. See http://www.gqrp.com/sales.htm. Members Price - only £34.00 (Non members £40)

The Limerick Sudden receiver kit

The GQRP club has launched a new kit called the Limerick Sudden. This was the message from George G3RJV today on the GQRP Yahoo Group:

"Limerick Construction is an exciting new way of construction. Conceived by Rex Harper, W1REX, of Limerick Maine it offers a simple and attractive way of building equipment. Based upon the Manhattan construction method (surface mounted parts on insulated pads) it also lends itself to the production of easy to build kits.

For some months G3RJV, G3MFJ and W1REX have been looking into producing a basic receiver kit in Limerick format. The resultant project, based on the G3RJV Sudden is now available in kit form. See http://www.gqrp.com/sudden.htm . It is complete in every way ... all parts... board ...case...no coils to wind ... even a battery! We hope members will enjoy our new Club Sales offering. "

Haiti appeal - our help is needed

It was good to hear that the GQRP club made a donation to the aid appeal for the survivors of the terrible earthquake in Haiti. The sheer scale of this is terrifying but, if we can afford to do so, we ALL need to give something to help these poor people. In the UK donations may be made on-line via the Disasters Emergency Committee website.

GQRP Club SPRAT 140

The latest copy of GQRP's quarterly magazine SPRAT arrived here today and it was nice to see my little Sixbox 6m AM transceiver featured on the front cover, alongside my car keys! Also in this edition was my article about WSPR weak signal beaconing. Since the article was written back in the summer I have been using WSPR almost daily on all bands from 500kHz up to 50MHz.

Just £6 annually gives you GQRP Club membership with 4 article-packed issues of SPRAT magazine a year, as well as access to the GQRP QSL bureau and club sales items such as toroids, QRP frequency crystals, transistors and ICs at good prices. As a GQRP club member, you can get a CD with all 140 editions of SPRAT magazine for just £4. It's worth joining just for this alone. If all other magazines had to go then SPRAT would be the one I'd still get as it is the best.

10m (and 15m) DSB rig ideas

The GQRP club sell xtals for 24.906MHz for £2 each. They also sell 3.58 and 3.68MHz ceramic resonators at 50p each. Now, mix 24.906 with either 3.58 o 3.68 with an NE/SE602 and you end up with a stable and simple mixer-VFO (when the ceramic resonator is pulled in a VXO) covering two very useful parts of the 10m SSB band or the 15m SSB band. All it needs is a filter on the output to select 10m or 15m injection. I have ordered the xtals and ceramic resonators and will start on the mixer-VFO when the parts come.

My idea is to use the VFO with a simple DSB TX and DC receiver. Such an arrangement will give a simple 10m (or 15m) DSB transceiver covering very useful parts of either band, but with few parts.

GQRP Club and SPRAT

Attached is the 6V6 valve transceiver by Geoff, G3YVF, from SPRAT magazine number 137 (Winter 2008/9). It uses 19 parts in all.

Join the GQRP club and receive the excellent SPRAT magazine every 3 months. The fee is only £6 per year (or equivalent in other currencies) which is excellent value. See: http://www.gqrp.org/join.htm for details on how to join. You can now pay with Paypal too if you prefer. BTW, if times got hard and all other radio mags had to go then SPRAT would be the one I'd keep.

Every quarter SPRAT is packed with circuits, ideas and news of interest to those who enjoy QRP. Back issues of editions 1-132 are also available on a GQRP club CD for just £5 if you are a club member.