10 Sept 2009

Electricity from trees?

A company called Voltree has some information on a system that generates electrical power from living trees. No, this is not a joke. See also the article on this in New Scientist magazine today.

Power levels are low, but the people involved believe there is enough energy to power monitoring systems and alert people of forest fires using energy derived from trees.

WOLF mode on 500kHz

Just set up my PC to receive and decode LF signals on 136kHz and 500kHz using a very weak signal mode called WOLF. DL4YHF, has written a GUI program to run WOLF and it's available at: http://freenet-homepage.de/dl4yhf/wolf/index.html . The program itself is available at: http://freenet-homepage.de/dl4yhf/wolf/wolf_gui_060118.zip . You need to unzip this and run the WOLF_GUI.exe file. Having set this up I am now waiting for some activity in this mode to take place so I can see if it all works. Last night M0BMU was active on the mode on 503.5kHz and was widely reported around the UK and Europe.

9 Sept 2009

Human hair solar panel??

The Daily Mail carried an article yesterday about an invention by a boy from Nepal for a solar cell array using human hair. The article claimed huge cost reductions compared with conventional solar panels. This sounds a bit like cold fusion and needs peer reviews by respected scientists in the developed world. It would be nice if was true.

BTW, do YOU still believe there was something in cold fusion?

10m WSPR (inter-G)

This afternoon I left the WSPR beacon running on 10m. Although the band was quiet, there was a weak trace that appeared and then faded out. It turned out to be G3JKV some 123kms away by tropo. On the stronger traces around 1422z you can see additional Doppler shifted lines as a result of aircraft reflection.

8 Sept 2009

160m WSPR

On 160m I have an almost useless antenna by accepted standards: just 15m of low wire down the garden and a central heating ground. Not only that, but my Elecraft auto-ATU cannot find a match on 160m. So, I get around this crudely by putting a 1dB pad between the antenna and the auto-ATU and it then manages to find a match. OK, I lose another 1dB but that is a fraction of an S-point.

Now, even with this crude set-up I have had reports from G, GM and PA0 on WSPR running 5W (less 1dB) into the antenna, proving that a piece of wet string is very nearly all you need to get out. Clearly, with a bit of effort I could make at least 10-20dB improvement on my signal - adding loading coils in the antenna, running out more wire and higher up, improving the ground system etc. I shall need to all of these if my efforts on 500kHz are to come to anything.

10m short skip still about

Although the main sporadic-E season is drawing to a close now, there are still some useful openings to be found, especially around lunchtimes and early evening. Lunchtime Sept 8th the band was open to central Europe with several 5W QRP SSB contacts possible, one to a mobile on the move in E. Berlin.

Never give up on 10m. If all else fails, you can always do a bit of WSPRing and see what surprise openings appear.

7 Sept 2009

500kHz TX activities - closer

In recent days there has been an upsurge in interest in WSPR beaconing on 136 and 500kHz with loggings now running into thousands whereas only 1 month ago there was hardly any WSPR activity on these LF bands. I am now regularly listening on both 136kHz and 500kHz WSPR.

My next priority is to get a basic 500kHz WSPR TX capability in place, if only a few watts to my very inefficient antenna. Once I get a signal of any kind I can start to improve the antenna and ground system and see how reports develop. The most probable route will be a transverter using the FT817 as the prime mover using an SBL1 mixer and a small IRF5xx FET PA This may take a few weeks, but I hope to have something on the air in October.

2 Sept 2009

6m aircraft scatter

Just been WSPRing on 6m and spotted G3ZJO, who is 79kms from here, by aircraft scatter. This is clear from the WSPR waterfall display which shows all sorts of Doppler shifted traces as well as the one that was successfully decoded. I suspect this is aircraft stacked over, or approaching or leaving, Stansted or Luton Airports.

1 Sept 2009

More on the active LF antenna

Yesterday I used a PA0RDT designed active antenna (but with MPF102 and 2N3904 devices and a 9V supply from a PP3 battery)to listen successfully on both 500kHz and 136kHz. This is a bit better picture of the antenna. Although it is recommended it is mounted well in the clear and away from the house (feeding the power up the coax), I just stuck mine onto my double glazed window - it still worked and heard stations on both LF bands. This is the ENTIRE antenna - no wire is needed down the garden.

In the last few days SM6BHZ has been heard in central Bejing China using a version of this antenna.

Guess what? A SUNSPOT!!!!

Hang out the flags - there is a sunspot on the surface today!