7 Apr 2017
Sunspots and 10m - Friday April 7th 2017
Solar flux is 85 today and the sunspot number 38. A=7 and K=2. What will 10m bring today?
Swallows return
Today we spotted our first swallow (bird) this year flying N-S over the allotments behind Burwell Museum at breakfast time this morning. In a few weeks they will be common!
April 7th is one of the earliest times I have seen these up here, although there have been reports in Devon a few weeks ago. There were days when I thought I would never live to see this day. The cycle of life goes on.
See https://www.rspb.org.uk/birds-and-wildlife/bird-and-wildlife-guides/bird-a-z/s/swallow/
April 7th is one of the earliest times I have seen these up here, although there have been reports in Devon a few weeks ago. There were days when I thought I would never live to see this day. The cycle of life goes on.
See https://www.rspb.org.uk/birds-and-wildlife/bird-and-wildlife-guides/bird-a-z/s/swallow/
10m JT65 again
G4KPX (14km) spotted me earlier this morning. I shall be sticking with 10m JT65 most of today again, although I am unsure of HF conditions. 10m has been quite good of late.
UPDATE 2200z: G6SSN (75km) spotted me on 10m JT65 and called me this afternoon, although I was beaconing at the time.
UPDATE 2200z: G6SSN (75km) spotted me on 10m JT65 and called me this afternoon, although I was beaconing at the time.
6 Apr 2017
Alien planet with atmosphere - NOT amateur radio
The BBC reports they have detected a planet in a distant solar system that has an atmosphere. With a surface temperature of 370 deg C it is unlikely to support life as we know it.
See http://www.bbc.co.uk/news/science-environment-39521344
See http://www.bbc.co.uk/news/science-environment-39521344
Cambridge Grand Arcade - NOT amateur radio
Return to 10m JT65 (2W)11448km
Quite late this morning, I returned to 10m JT65 transceive running 2W. As yet no spots.
UPDATE 1400z: Still no 10m spots today so far.
UPDATE 1530z: Still no 10m JT65 spots here today. The rig and PC will be on for several hours yet.
UPDATE 2114z: G0LRD (25km) is my best TX DX today. LU1ECO (11448km) was the most distant station on RX.
UPDATE 1400z: Still no 10m spots today so far.
UPDATE 1530z: Still no 10m JT65 spots here today. The rig and PC will be on for several hours yet.
UPDATE 2114z: G0LRD (25km) is my best TX DX today. LU1ECO (11448km) was the most distant station on RX.
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
5 Apr 2017
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.
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"
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.
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"
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