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?

Rural Suffolk - England at its best

We are blessed with a wonderful variety of scenery and plenty of still quiet rural countryside to enjoy despite our cities being crowded. This afternoon my wife and I enjoyed a ride through rural Suffolk in East Anglia where we stopped at a number of delightful small churches.  There is a lot to be grateful for in an English summer with a gentle breeze, warm sunshine and the sound of swallows, woodpeckers and bees overhead.

Wispy WSPRs

Overnight I was looking for MS propagated WSPR signals on 10m. There were a few early morning decodes as well as plenty of evidence of MS bursts which were too short and too Doppler shifted to permit successful WSPR decoding.

Perseid meteor shower

Overnight tonight the Perseid meteor shower will peak with some dazzling displays in the early hours of Saturday morning if the sky is clear. With luck, MS conditions will be good on 10m, 6m, 4m and 2m with some long bursts. Not sure what band(s) to monitor but may see what can be heard/seen on JT6m on 6m.

Inside a QRPer's brain

G3XBM's brain!

Today I had my brain scanned for scientific research. For several years I've volunteered as a guinea pig at the Centre for Speech, Language and the Brain at Cambridge University.  It involves doing the occasional language test and about once a year having an fMRI scan whilst doing some task involving language. The university has its own MRI unit for medical research. The whole MRI thing is painless and is actually rather relaxing, especially when they are doing a full scan and the machine is vibrating which is like having a massage. If anything untoward is seen in the scans they inform your doctor, which is good. Let's hope that it looks OK. Certainly it looks much like the one I had done a few years ago.

The purpose of the research is to better understand how the brain functions and they hope this will help with people recovering from strokes.  It must be so rewarding to be working in this field either as a PhD student or as a post-doc researcher.