10 Feb 2010

QRP DXing on 15m CW

With the improved sunspot count yesterday and today 15m has opened up to the Caribbean and to the USA this afternoon. First QSO was 9Y4VU at 1400z then WX3B at 1450. Both were with 5W CW into my 500kHz vertical via the T1 auto-ATU.  I did take a quick look on 10m, but nothing heard hear. Later I took a go at PSK31 and worked RA3GI and US2IR on 15m with around 3W. It is so good to hear the higher HF bands coming back to life again: it has been a long time mostly quiet but the GOOD times are back.

8 Feb 2010

Sunspot count - 51

Just seen the sunspot number - 51. Things are looking up. If anything, I think that the rate of improvement in sunspot activity is slightly ahead of predictions. Maybe we'll have a bumper cycle 24 peak after all. Only time will tell.

Update: the count today is a staggering 71!!

VK2ZAY's version of the XBM80-2 transceiver

A few more people have been making the XBM80-2 transceiver. One is Alan Yates VK2ZAY who has made a de-luxe version with some refinements and additions. See it on his blog at http://www.vk2zay.net/article/238

6 Feb 2010

Problem with Sprint Layout 4 PCB package

Trying to do a small PCB for the XBM80-2 80m micro-transceiver using the Sprint Layout 4 PCB layout package I hit a problem: wanting to use a single sided PCB for low cost I did a groundplane fill. Then I wanted to connect certain pads to this. I cannot see how to do this! Several people have offered advice, but nothing seems to work: any attempt just results in a new clearance area being created. In the end I gave up and filled in the ground as another track and join it to the pads manually. The resultant draft PCB (1 inch square)  is shown here. I have not built it on a PCB yet, so this is only a suggestion. An SMT version could be half the size - i.e. VERY tiny indeed.

5 Feb 2010

XBM80-2 video and PCB (draft)


A short video about the XBM80-2 80m CW micro-transceiver. This is built "ugly style" on a piece of copper clad board. It will get put in a box soon! I've also been having a go at a PCB (just 1 inch square - 25mm x 25mm).

4 Feb 2010

Back on 500kHz tonight


Having been playing around with the XBM80-2 80m micro transceiver for a couple of days, I've not been on 500kHz for a bit. However, I am back again tonight with the 1mW ERP WSPR beacon. Reports from LA3EQ and GM4SLV amongst others received so far.

3 Feb 2010

Prosperity without Growth?

Prosperity without Growth? - The transition to a sustainable economy is a freely downloadable publication from the UK's Sustainable Development Commission. The report calls on world leaders to adopt a 12-step plan to make the transitionto a fair, sustainable, low-carbon economy.

Improvements to the XBM80-2 80m QRP transceiver

A few small value optimisations have improved the XBM80-2 transceiver. I've optimised the collector circuit values and this has resulted in 120mW output (was 60mW) from a 12V supply. The sensitivity is a little higher, the backwave level is lower, the amount of AM breakthrough from medium wave broadcasters is lower. At 4pm I was hearing DR2010O in the Ruhr area of Germany working all over Europe and could copy almost all the stations that he was working but I failed to break the pileup with 120mW. I'm beginning to think this little transceiver could be really useful. There is no reason why it should not work well on any band up to 28MHz (with less output) with a fundamental crystal. I'm wondering how it will perform on 50MHz with the collector tuned to x2 crystal?

1 Feb 2010

XBM80-2 heard at 430kms

This evening I tried listening for my 60mW CW signal from my XBM80-2 80m micro-transceiver on the on-line SDR at Twente in Holland. The signal was clearly audible at RST529 when I keyed the transmitter slowly! Distance is 430kms (267miles).

Another XBM80-2 QSO tonight

This evening I worked G6ALB 3kms away on the XBM80-2 60mW ultra-simple 80m transceiver getting a 599 report. Andrew was copied at 599 when he was using his 300mW TR6C4 simple valve transceiver which has a regen RX. Andrew also sent test transmissions using his signal generator and I was able to copy his signal when he was running 3mW output. So, the conclusion is, as AA1TJ has already proven, the design is quite a useful one and VERY simple.