Sunspots and 10m - Thursday April 6th 2017

Solar flux is 83 today and the sunspot number is 37. A=10 and K=1. Yesterday was good on 10m JT65 with my 2W spotted in Brazil for the first time this year.

Eating out - NOT amateur radio

Most of the last week we have had the "London" grandchildren staying. A few days ago we went to Cambridge and ate out at a small independent café called Le Patissier which is opposite St John's College. The food was good, prices reasonable and staff friendly and this is the fourth time I have eaten there.

New amateur record at 970Hz

From Stefan DK7FC:

"Hi ULF friends,

Saturday night i build an active E field receiver optimised for ULF. It is using a BF862 front-end as a source follower and a LT1028 with 20 dB gain. There are 3 RC filter stages cutting off at 10 kHz. Furthermore there are two isolation transformers in series, 4:1=>1:10. In the center they are parallel resonated. This gives a further good low pass filtering and some additional gain below 3 kHz. It was a quick construction without thinking to much, soldered at night, 02 AM local time. The antenna probe is a 1m long steel rod (for welding) with 2 mm diameter. The antenna height above ground was just 2m. There were no trees in a radius of 20 m.

For transmitting i'm again using the modified 5 kV mains transformer. At 970 Hz, the antenna impedance is 342 kOhm! So i can just run 15 mA antenna current which means 3 nW ERP. The new ALC build inside SpecLab holds the 15 mA accurately and protects the transformer that way! SpecLab is a very well usable tool for transmitting on VLF/ULF, thanks to DL4YHF!!
The transmit frequency was 970.005 Hz.

I didn't expect much, thought that this distance may be to optimistic. The last signals were very weak on my tree grabber in 3.5 km distance. But that tree grabber is using loop antennas and they are not sensitive in that frequency range. So there was a certain chance to see a trace, maybe in 212 uHz???
I drove to JN49JL00EB and built up the receiver there because it is a quiet location, a nice region for a walk and, there is a good restaurant not to far!!!!!! So it was easy to spend some time there and let the Raspi (using a GPS module on the right soundcard channel, with PPS+NMEA) record for nearly 3 hours at 24 kS/s.
This is the path between TX and RX: http://no.nonsense.ee/qth/map.html?qth=JN49JL00EB&from=jn49ik00wd  A distance of 7.2 km, or 0.023 wavelengths or 14% of the distance to the far field border. So it is still a near field experiment.
It is about twice the distance i've managed in the last test.

Now i'm back in the shack, analysing the recording and to my surprise i can see a strong trace of 30 dB SNR in 424 uHz!!! See attachments in 424 uHz and 3.8 mHz.

All this makes me much more optimistic to reach farer distances. I tell you i will crack the far field border on that 309 km band! That would be a distance of 49.3 km.

There must have been some local thunderstorms not to far away, because there was QRN in the observed spectrum. So the SNR can be improved a bit by doing the next test in the late morning hours. Also the resonance of the transformers seem to be a bit to low, so maybe i can reach a bit more sensitivity when optimising that resonance. It could further help to rise the effective height of the antenna. Flat fields rather than the deep forest is the region to select now....

73, Stefan"

OFCOM and mobile repeaters

OFCOM is consulting on mobile repeaters.

See http://ofcom.cmail19.com/t/ViewEmail/i/26E022FC8AA20F74/59D1BD3EA2F08127C67FD2F38AC4859C

Tawny mining bee - NOT amateur radio

For several days now, I have seen little mounds of soil with a hole in the middle in my grass. For a while I thought this was ants then I saw a bee. Further research has pointed me to Tawny Mining Bees. These are solitary bees that don't live together. They are small bees with ginger hairs.

See https://en.wikipedia.org/wiki/Tawny_mining_bee .

10m JT65

Although no spots seen as yet, I have been on 10m JT65 today. We are nearing the start of the Es season which should see 10m and 6m open to lots of Europe from the UK even with QRP SSB.

UPDATE 1920z:  No spots all day, at least not showing on PSK reporter maps. Still running overnight, so might catch some aircraft reflections later?

UPDATE 2032z: PY2RSA (9473km) spotted me on 10m JT65 not too long ago. Not shown on PSK reporter maps was a spot of an N0. This may have been because I lost internet connectivity for a period. I have since gone QRT.

Sunspots and 10m - Wednesday April 5th 2017

Solar flux is 93 today and sunspot number 75. A=20 and K=2.

OFCOM Update

Every month, OFCOM produces a "Communications Update". This is the latest version.

See http://ofcom.cmail19.com/t/ViewEmail/i/8EAFA4273AD97B72/59D1BD3EA2F08127C67FD2F38AC4859C

St Johns, Cambridge - NOT amateur radio

The colleges at Cambridge University are always worth a visit, but they look so good in spring. This was the view of St Johns this afternoon. We just missed the rain.

Sunspots and 10m - Tuesday April 4th 2017

Solar flux is 106 today. Sunspot number is 97.  A=4 and K=3.

See http://www.solen.info/solar/ for a summary of the latest solar data. Last month, the smoothed sunspot number declined to 22.6, but this month has got off to a promising start.