26 May 2011

The Elecraft KX3 Ultra-portable multimode QRP rig

There is much excitement about the latest product from Elecraft, the KX3. This was announced at Dayton and it looks like a marvellous addition to the Elecraft range. See http://www.elecraft.com .

The RSGB Luso Tower fiasco

Some time back, the RSGB bought a huge Luso tower - list price £31k, although they got it for less - but are now selling it for £13.5k as they can't get planning permission for it at their new home at Bletchley Park.  What has this sort of monster got to do with amateur radio? What sort of example is our national society giving to newcomers? Pay BIG money for everything to get a BIG mast, BIG yagi, BIG rig and BIG linear?

The RSGB must give more of a lead by showing that this does not have to be a "fat cheque book" hobby and that simple, low cost, equipment can be effective. RadCom does carry some excellent articles, but I fear many newcomers reading the magazine would come away thinking it's an expensive hobby.

25 May 2011

10m Sporadic-E and BIG signals

As an example of just how strong signals can be on 10m with strong Es conditions take the reports this afternoon from DJ0ABR. With 500mW to my halo he was giving me a WSPR report of +7dB S/N. This suggests I'd still be OK with just 500uW from the transmitter. I know others have achieve far better than this but it does remind you that a big sporadic-E "cloud" acts as a very good mirror.











Sepura introduce intrinsically safe TETRA portable

My colleagues at my old company, Sepura, have just released details of their new ATEX intrinsically safe TETRA portable. From my own experience of designing intrinsically safe products (PF2UBIIC, EXPF85) this is a far from easy task, especially today when the tests are even more extreme and challenging. Well done to the team involved.

Intrinsically safe radios are designed to be used in very hazardous locations such as oil refineries or petrochemical plants where the risk of explosion is high. They are designed to be safe even in certain fault conditions.

My first JT65 QSO

Although I've listened/looked at received signals with this mode, this morning I had my first ever JT65 QSO (using QRP of course) with EA1YV on 14.076MHz. I used the JT65-HF package with the simplified interface for HF QSOs. It worked a treat. See http://physics.princeton.edu/pulsar/K1JT/JT65.pdf.

As I've no antenna for 20m I just used my 10m halo tuned via the Elecraft T1 auto-ATU.

24 May 2011

4m transverter - some builder feedback

Just got this very nice email about my 4m transverter:

Hi Roger,
               My name is Mark (mi0bdz) and I was browsing the net for 70mhz projects when I came upon your site. I could hardly believe the simplicity of the little 70mhz  transverter you designed and built. I decided to copy it. I started on Friday afternoon after gathering the bits together and completed it by Saturday evening. I could not have done this without thanking you for sharing the project,  which I class as the best usable project I have come across in many years.
   I have found that by careful selection of the TX transistors and bias resistors that 3 watts is possible. I did have to alter the values of the bias resistors quite a bit, but that is all. Everything else is as your schematic. Thankyou again for a wonderful little project. This is a gem. The sensitivity is also excellent. You were right about packing a lot into a chip indeed. Thanks again Roger.

  Regards
             Mark

23 May 2011

Cycle 24 already peaked?

Check out recent trends - it looks like the present cycle has already passed it's peak. Or is this just a blip?

22 May 2011

6m Es

Well, the 6m sporadic-E season is in full swing again: yesterday loads of Europeans worked with QRP and the vertical and this afternoon being spotted in Spain with WSPR. Initially it's fun working around Europe, but as the season goes on the real excitement is further afield looking for US/Canadian and South American stations on 50MHz. It never fails to amaze me how far one can hear/work on 50MHz with the right conditions. Also, next month should see the return of UK-Japan openings on 6m possibly as a result of reflections/scattering from high altitude noctilucent mesospheric clouds; signals with this mode are usually very weak.

18 May 2011

Old QSL cards

Clearing the loft today I came across several QSL cards from my first year in Cambridge back in 1971 including this one from Bob G3WKW for a QSO across town using my 1 transistor 2m TX on CW and FM. I cannot recall the details or how I obtained the FM. Power was just a few milliwatts into a dipole in the downstairs room in a terraced house. Bob went on to work for Motorola before retiring in Hampshire a few years ago. We still keep in contact.

15 May 2011

137.5kHz WSPR

Several stations on 137.5kHz WSPR tonight. G4WGT is testing a new rig, M0PPP is getting decent reports and me getting reports from just G3XIZ so far. Will leave WSPR running for a few hours and see what happens.