Back on 500kHz WSPR

This afternoon John GM4SLV informed me he was restarting tests on 500kHz WSPR from way up in the Shetland Islands with about 150mW ERP.  So, I've fired up my own 500kHz WSPR system in the hope of copying him later this evening. So far I have had spots of my own 1mW ERP signal from several stations with best DX so far being PA3ABK at 306km, but nothing seen (yet) from John. I'm hoping a few more stations will appear too.

http://goo.gl/

Just discovered Google also do a "shorten your URL" feature too. Go to http://goo.gl/ to try it out. I knew about tinyurl but only just noticed the Google equivalent. As with other shortened URLs, some security systems may recommend avoiding such links.

Bitsbox - an excellent UK component supplier

Just a couple of days ago I placed an order with Bitsbox, a UK component supplier for a variety of components needed in my upcoming VLF/LF experiments. Today, by first class post, the order arrived. Bitsbox charge a fixed £1.50 first class post charge which is very reasonable. The service and value for money are truly excellent. Their website is www.bitsbox.co.uk  and they stock a wide range of useful parts.  If you've not used them before, and I had not, I can highly recommend them.

Heathkit kits again?

The Southgate amateur news page carries a story that Heathkit may be about to start the production of kits again after a break of many years. This would be excellent news. Heathkit used to produce world class kits that were in a class of their own with first class instructions. Let us hope they decide to restart amateur radio kits as well in due course. In the amateur radio field Elecraft are the nearest.

500kHz

With the autumn season not too far off I am turning my thoughts to 500kHz and 136kHz again. This weekend I hope to return to 500kHz WSPR as GM4SLV is testing his new 500kHz antenna and ATU. After that it will be my turn to improve the ERP on 136kHz with a new PA, ATU and antenna.

Antenna folklore

From the LF-reflector and very true.

Antenna engineers use to say about design goal limits of antennas:

    Small
    Efficient
    Wideband

Pick any two (meaning you can't have all three...).

73   Clemens   DL4RAJ

Inter-G 10m DX with 5W WSPR

In the last 24 hours, as well as some excellent long distance DX, I've been surprised by the 10m reports from stations within the UK. For example G4CUI in IO93 and G6BHS in IO81, both around 170km. These are not one-offs as exchanges with G4CUI are common at almost any time. I must keep a record of all the QTH locator squares I get reports from on 10m and 6m WSPR from within the UK. WSPR is an excellent mode for "sniffing out" openings.

Chile on 10m WSPR

Just exchanged WSPR reports with XQ6FOD in Chile at 12285km on 10m this evening at 2054z. At first I thought this was a bogus report but checking on QRZ.com the call is genuine. I think this was Es linking into some TEP F2 propagation as I was getting good reports from Spain.

Good Es DX on 10m

This afternoon I put my WSPR beacon on 10m for a while and was surprised how wide open the band was. Strong Es signals from across Europe and N.Africa plus a couple of excellent reports from R9SA in LO71 square at 3661km to the east. I'm wondering if the band will open up across the Atlantic today. Even with 500mW I was getting very good reports. Reports from OY1OF suggest even 500uW would be enough for a report.

Best results yet on 8.76kHz earth mode

8.76kHz earth mode signal in 45mHz BW at 6km

This morning I slightly changed my VLF low input impedance tuned preamp by increasing the tuned circuit Q and gain of the first stage by around 6dB. After lunch I did a test at 6km from home to see what effect this had on the S/N of my 5W beacon. In a 45mHz bandwidth (previously 11mHz) I was getting a signal around 18dB S/N using Spectrum Lab on my 80cm square loop on the ground. With an earth electrode antenna the signal was marginally weaker and the noise level higher.

My signal is the steady carrier (with a 2min ID break) at 8.7605kHz. The large wobbly line is interference, but who or what is the signal at 8.754kHz? This is rock steady and appears to key on and off every 5 minutes. It looks like some sort of control signal, or is someone else near Cambridge testing?