17 Aug 2010
Chinese SSB and CW transceiver kits/built
YouKits of China is advertising a new 6 band HF SSB transceiver, the TJ6A that is available both in kit form and ready built. Prices look very attractive for a 10W transceiver. Well worth a look at their website. This last year we have begun to see Chinese ham products appearing. It is only a matter of time before a Chinese manufacturer will produce quality transceivers to seriously rival Icom and Yaesu, and at unbelievable prices.
Pakistan Floods
This map appeared on the Oxfam site today and gives a graphic indication of how much land is affected by the floods in Pakistan when overlaid on a map of the UK. It must be truly awful for the poor people there affected by this with crops, homes and businesses in ruin. Just imagine if this happened here (see map) and think how we would like the rest of the world's governments and peoples to help.
Help here: http://www.oxfam.org.uk/get_involved/campaign/actions/pakistan_response.html
Help here: http://www.oxfam.org.uk/get_involved/campaign/actions/pakistan_response.html
Labels:
oxfam,
pakistan floods
ICQ Podcast: LF/VLF and QRP stuff
Last week Martin M1MRB interviewed me by Skype for an ICQ Podcast mainly about LF/VLF and QRP . My contribution starts about half way through the podcast. Thankfully Martin edited out many of the "ums" and "errs" that littered the piece!
16 Aug 2010
Resonating the earth electrode antenna on 136kHz
The 20m spaced earth electrodes "antenna" has about 30m of wire coming back ato low height to the feedpoint upstairs. I wondered if I could increase the current flowing into this structure by tuning out the small inductance presented by the wire. Using a small capacitance switching box I selected the value that gave most current with the 2W beacon TX. It was 100nF although because of the resistance of the ground return path the Q is low and the peak small. This suggests the inductance of the feed wire is only 13.5uH. I also tried matching the loop using a 3C90 transformer with various secondary taps but this made little difference. So, conclusion is that resonating the loop and matching it makes very little difference to the current (and ERP) because of the low Q.
Labels:
136khz,
earth electrodes,
loop
15 Aug 2010
136kHz with a vertical antenna ....8uW ERP
Having simply tuned and matched my 5m coax feed to the 28MHz halo (the halo is used as a top capacity hat) I'm now putting out the grand level of 8uW (+/-3dB) on 137.675kHz in QRSS3 from my 2W out beacon TX. Tuning was with 1.2mH wound on a small piece of ferrite in parallel with some fixed and variable capacitance. Matching was via a 3C90 toroid transformer. Field strength tests a few km away from the QTH suggest that the ERP from the earth electrode antenna is higher than this vertical, which is a bit disappointing as it suggests the vertical is, well, poor.
14 Aug 2010
Old UK radio and TV clips
If you were young in the UK in the 1950s you may be interested in these two sites dealing with radio and TV in the 1950s. There are many old clips that take you back nearly 60 years.
http://www.whirligig-tv.co.uk/ radio/index.htm
http://www.whirligig-tv.co.uk/
http://www.whirligig-tv.co.uk/
http://www.whirligig-tv.co.uk/
Labels:
1950s,
bbc,
cave radio,
tv
13 Aug 2010
Back on the vertical on 500kHz
WSPR Reports today |
300% more efficient wind turbine?
Japanese professor Yuji Ohya and his team have investgated the design of wind turbines and suggested a honeycomb-like structure could triple the amount of wind energy that can be produced by offshore turbines. See Tech Future site for more information.
Labels:
wind power
12 Aug 2010
Perseids meteor shower tonight
The Perseids meteor shower is supposed to be a strong one peaking this evening. I may run the WSPR software overnight on 10m to see if any bursts are long enough to support a 2 minute WSPR transmission.
LATER: Overnight I copied PA0PSY at 0044z by what looked like MS: quite strong signal, seen once only, with Doppler, over a 300km path, although it could also have been aircraft reflection. Unfortunately I didn't see the WSPR screen to examine the actual screen trace.
LATER: Overnight I copied PA0PSY at 0044z by what looked like MS: quite strong signal, seen once only, with Doppler, over a 300km path, although it could also have been aircraft reflection. Unfortunately I didn't see the WSPR screen to examine the actual screen trace.
Sunspots - high 60s
Have you noticed how high the sunspot count is climbing? Today it is 66 or 70 depending on which measure you take. This is not far off the sunspot count predicted at the peak of cycle 24 in about 3 years' time. If this trend continues, we could be in for a bigger peak than some were predicting. It could by just a blip.
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