29 Jan 2010

Nuclear Fusion breakthrough?

Some recent research may have helped the dream of unlimited and pollution-free energy from nuclear fusion become a big step closer. Scientists in the USA have demonstrated that containment of atoms for fusion using laser beams is far less problematic than first thought. Unlike current nuclear fission, nuclear fusion reactions create no radioactive waste materials. Potentially nuclear fusion reactors, if created on a commercial scale, could dramatically help supply clean energy the world so badly needs. See http://news.bbc.co.uk/1/hi/sci/tech/8485669.stm

Super-efficient VHF antenna?

See http://www.nist.gov/public_affairs/techbeat/tb2010_0126.htm#antenna
"The National Institute of Standards and Technology (NIST) and partners from industry and academia have designed and tested experimental antennas that are highly efficient and yet a fraction of the size of standard antenna systems with comparable properties. .....NIST engineers are working with scientists from the University of Arizona (Tucson) and Boeing Research & Technology (Seattle, Wash.) to design antennas incorporating metamaterials—materials engineered with novel, often microscopic, structures to produce unusual properties. The new antennas radiate as much as 95 percent of an input radio signal and yet defy normal design parameters."

28 Jan 2010

Mosquito single IRF510 transceiver

EA3GHS and EA3FXF have produced a single IRF510 FET based version of his Mosquito transceiver using a PC as the back end of a software defined radio (SDR). In essence, the FET is used as a regenerative or direct conversion receiver - I think the two are indestinguishable in a single stage RX - with audio coupled to the sound card via a mains transformer which steps up the impedance. The IRF510 is capable of up to about 7W in this application. Coupled with an SDR back-end and this is SOME simple transceiver, especially if the crystal is VXOed.

Web based HF receivers (SDRs)

Web software defined receivers (SDRs) are becoming quite common now. They allow you to eavesdrop on a number of different HF bands and tune around for stations as if you're located at the distant location. The best place to find a list of these receivers is at http://www.websdr.org/ . I have used the one in Twente, Holland to see if my QRP 80m signal got to The Netherlands (it did) and to check activity on bands like 500kHz. Sometimes these SDRs are located in places where the background noise levels are very low too.

27 Jan 2010

Apple iPad tablet launched

Apple has finally revealed its new killer product - the iPad. My son has an iPhone and is very pleased with it. I doubt I will be persuaded to buy either. I have been tempted with the Apple iPod Touch which is a very desirable product.

26 Jan 2010

500kHz again tonight

After a break of a couple of days, I'm back on 500kHz WSPR again this evening with my 1mW ERP. The reports are still coming in from far and wide (G, GM, PA and LA so far), although no super-DX from central Europe yet this evening.

25 Jan 2010

Walford Kits "Fivehead" SSB transceiver

A friend of mine is building a Walford Kit "Fivehead" SSB transceiver. He has got the kit, but was surprised to find the parts placement was not silk screened on the PCB; I guess this is a cost saving measure.

Although there is a not-to-scale layout, a clear colour photo from above of the assembled board from the component side would help him a lot. He's asking Tim if he has one he could email, but does anyone already have one they could email me please?

XBM80-2: a 2-way QSO and report

This morning I worked M0DRK using my tiny 60mW XBM80-2 transceiver I designed last week. It uses just 13 parts plus the crystal, earpiece and optional frequency offset switch. My report for Derek was 599 and he gave me 599+40dB. Derek is in the same village. Also monitoring was G4LHI in Huntingdon 32kms away and he reported my signal was as strong as Derek who was running 5W.  In fact 60mW is only going to be about 3 S points down on 5W. I also heard GM3JUD when listening on the XBM80-2 on 3.560, but was unable to raise him.

23 Jan 2010

Shortwave in the 1960s - interval signals montage

Yesterday I found this wonderful link which is a montage of 40 different old shortwave interval signals from almost 50 years ago. Get a coffee, sit back and listen.  Imagine you are listening on your one valve radio in your bedroom in 1964.  It brings back such happy memories that I am almost tearful with nostalgia.

http://garlinger.com/QSL/montage.mp3

G3ZJO in QRSS3 on 500kHz

G3ZJO has a QRSS3 beacon sending in FSK built in Altoids tins and running QRPp power. This is is a screenshot (from Spectran) of his signal this afternoon. I have superimposed his callsign, which is clearly visible on the upper line. The first dash of the G in his call is missing in my capture.