500kHz antenna video

As it was a nice snowy day I took a short video of the 500kHz spiral top loaded antenna that I use for my WSPR testing on the band. The spiral part is hard to see but consists of 8 turns of wire spiralling into the centre on top of the 5m vertical section. There is also a further brief video showing the end of a 500kHz WSPR transmission.

Uk 500kHz permits extended to 2012

Just seen this today on the LF reflector:

Ofcom has decided to extend the period of Notices of Variation (NoVs) to the licence for operation in the 501 to 504 kHz band until 29 February 2012. The maximum effective radiated power (e.r.p.) limit is maintained at 10 dBW (10 W).

Only another 40dB ERP to find then :-)

Is WSPR a good thing?

There's a letter in Jan 2010 RadCom about the use of WSPR on 500kHz that advocates keeping the band just for CW. I understand the sentiment, but WSPR is a very narrow band mode taking just 6Hz bandwidth for a single transmission, which may be sent for as little as a few minutes in each hour. Surely there is space for both WSPR and CW? Incidentally I've had several attempts at CW QSOs with quite strong stations on the band and, with a few exceptions, it has been hard to get a contact with my low ERP.

Not so with WSPR as I can get reports (via the database) day and night in great detail - reporting station's callsign, S/N level, distance, QTH locator, direction. All data that confirms the signal has propagated to the distant receiver. It allows me to see in a few minutes the effect of a change of propagation, antenna, ground, power output etc.

Also, take another example (reported in an earlier blog entry) on 40m this week. Noise level here was running at S8-9 and it was a struggle to hear much on the band. I go on to WSPR (running 5W to my 5m long vertical) and get a report within a few minutes from VK4YEH who was 16451kms away. On CW I would never have heard him and I doubt he would have heard me. With WSPR I KNOW that my QRP signal reached Australia.

Like many, I enjoy CW especially with QRP, but there is definitely a place for WSPR on ALL bands as a real means of experimentation with propagation, antennas and rigs.

Views please?

Video of the G3XBM shack

Just for fun, I've put a very short video of the G3XBM operating "shack" (actually a corner of the smallest bedroom) onto YouTube. It shows the current set-up of homebrew and commercial equipment in use as well as the 500kHz transverter. I do most of my construction elsewhere.

New 40m WSPR DX record (for me) - 16451kms

Just put my WSPR beacon on 40m a few minutes ago. First report was from a G station 44kms away. The next was from VK4YEH who was 16451kms away, a personal DX record with WSPR. Then in the following 30 minutes just G4AKU - I was lucky.

Sunspots - an improving picture

From http://www.wcflunatall.com/nz4o4.htm

Sunspot group #11035 has grown into the largest and most magnetically complex sunspot group of solar cycle 24. At 0102 UTC the sunspot group released a small C5.3 solar flare, the largest solar flare of solar cycle 24.  The sunspot count is 38 which is the highest of solar cycle 24. The solar flux index is 82 which is tied for the highest SFI of solar cycle 24.

I've got to get back on 10m in readiness for the good times ahead. Roll on 2010!

Idea for a simple 10m WSPR transceiver

GQRP club sells  inexpensive 14.060MHz crystals and these doubled would come out on 28.120MHz. I am wondering if they will pull UP to 28.1246? If so, they would make a perfect source for a DSB WSPR transceiver. Half the TX power would be wasted on a signal 3kHz lower but it would be a very simple design with just an oscillator, doubler, balanced mixer, PA and low pass filter, plus the basic audio input and DC receiver parts, which would re-use much of the TX design. Some experiments are needed!

Alternatively, can anyone suggest a more modern approach such as using a programmable reference oscillator as used in SDRs? What is the best one? Where do I get them from?

Linux Journal - special ham radio edition

The January 2010 edition of this US Linux OS magazine is a special one dedicated to amateur radio. Although I'm not a Linux freak, I'm sure that many readers will find it of interest.

See http://www.linuxjournal.com/ham

500kHz transverter boxed at last

Today I completed the 500kHz transverter by putting it in a small Maplin's ABS case with coax connectors and an on/off switch. Attached is a photo showing the transverter unit on the shack table and with the box lid open so you can see the completed unit. It has been a most enjoyable project. The schematic of the transverter is on my website on the "Operating on 500kHz" page.

On WSPR, I'm still awaiting my 50th unique report that I hope will come in the next few days before I take down the 500kHz antenna and reinstall my 28MHz halo.

Big Ben - a 119 year old recording

Not ham radio, but just spotted this fascinating recording of Big Ben chiming. It was made on a wax disc 119 years ago in 1890.