Nice eQSL card from PA6GST received today:
Wednesday, 19 May 2021
Friday, 14 May 2021
QSO with 9A and GI on 70 MHz
This afternoon some sporadic E clouds were present:
In the evening strong signals from Ireland and Northern Ireland appeared:
QSO's with GI4SJQ, GI4SNA and EI2FG were made.
Wednesday, 5 May 2021
Schottky diodes
A Schottky diode, also known as Schottky barrier diode or hot-carrier diode, is a semiconductor diode formed by the junction of a semiconductor with a metal.
Typical metals used are molybdenum, platinum, chromium or tungsten, and certain silicides (e.g., palladium silicide and platinum silicide), whereas the semiconductor would typically be n-type silicon.
Schottky barrier diodes have a low forward voltage drop and a very fast switching action (typ. 5 ns).
A silicon p–n diode has a typical forward voltage of 600–700 mV, while the Schottky's forward voltage is 150–450 mV. This lower forward voltage requirement allows higher switching speeds and better system efficiency.
Lately I purchased a bunch of BAT85 Schottky barrier diodes. A typical value for its forward voltage is 200 mV.
I replaced four Ge diodes by BAT85 Schottky diodes in my field strength meter. http://pa2rf.blogspot.com/2020/07/fieldstrength-meter.html?m=1 .
The performance of the meter has certainly increased (higher sensitivity).
More info:
https://en.wikipedia.org/wiki/Schottky_diode
Bunch of BAT85 Schottky diodes
Friday, 12 March 2021
ZX81
Bumped into my first ever bought computer. In 1981 (unbelievable, 40 years ago..) I bought this ZX81. Price at that time appr. 350 guilders. Learned BASIC programming with it. It was a splendid design from Sir Sinclair. Mind you, the computer had only 1 Kilo (!) Byte internal RAM. With an extension board on the backside (Memopak) an upgrade of 16 KB was possible :-). It contained a video modulator so you could use your (black/white) TV as a computer monitor. What was your first computer / PC ?
Tuesday, 2 March 2021
Fauna in the garden
This non-radio related post is just to collect nice pictures from my garden. I hope to contribute a small bit to the (animal) biodiversity in my neighbourhood.
2 May 2022
2 March 2021
16 June 2021
2 March 2021
Dagpauwoog
2 April 2021
12 April 2021
26 June 2017
12 March 2021
30 March 2021
2 April 2021
Thursday, 4 February 2021
UHF Power Amplifier
This UHF final stage is waiting for a heatsink to arrive.
Off topic 13 February 2021
De Kwade Hoek, near Havenhoofd, Goeree
Monday, 1 February 2021
North Sea Level rise
I have always had the idea, that past years the level of the North Sea has risen very rapidly. This is what the main stream media tries to make us aware of. Some meters rise coming years would be possible they say.
However, lately I bumped into this article:
https://klimaatgek.nl/wordpress/2021/01/17/de-zeespiegel-in-nederland-1901-t-m-2019/#more-7043
I found that the last 100 years the North Sea level rise is
lineair and does not show a grow acceleration. The absolute North Sea level
rise is appr. 15 centimeters in a century
(100 years).
This graph shows the average height of 6 sea costal
stations in The Netherlands.
In spite of this (only) 15 cm rise per century, I am not underestimating the forces of water and wind. I have a special interest in the sea level rise because I live on Goeree-Overflakkee. This island was struck by the ‘Watersnoodramp’ (North Sea flood) that took place in the night of 31 January/ 1 February 1953.
A combination of a high spring tide and a severe windstorm
over the North Sea caused a storm tide. Dykes broke and the sea flooded up to
about 6 meters above the mean sea level.
Today, this happened exactly 68 years ago. During this disaster 1836 people in Zeeland, Brabant and Zuid-Holland were killed. Also on the island where I live (Goeree-Overflakkee) more than 300 people lost their lives (Oude Tonge).
Today, many people in the neighbourhood commemorate the flood
and its victims.
Interesting story for radio amateurs: About 20 km from where
I live, in Zierikzee (capital city of Schouwen Duiveland), Peter Hossfelt jr. –working
in a radio store/shop - managed to make a 80 mtr band transmitter to inform the rest
of Holland about the disaster that had taken place. A replica of this
transmitter can nowadays be found in the ‘ Watersnoodmuseum’ in Ouwerkerk.
More: https://www.pa3esy.nl/zelfbouw/Watersnoodzender-1953/html/Watersnoodzender_set.html
Thursday, 14 January 2021
432 MHz FT8 contest
Yesterday evening I participated in the 432 MHz FT8 contest organized by ft8activity.eu
With my modest 10 Watt station I was able to make QSOs with PA3JQD, PE1NYQ, PA3FOE, PA3GUV, PA3EWP, G4PLZ, PA5Y, PE1LLZ and PE1NFT. I heard a lot of other stations. In PSKreporter I also found a lot of stations that heard my 70 cm station on 432.174 MHz;
The activity schedule of the 2m / 70 cm contest:
Tuesday, 29 December 2020
6 meter activity
December 28, there was a lot of activity on 50 MHz. Unexpected winter propagation conditions if you ask me. Here you see the stations that received my 15 Watt FT-8 signal on 50.313 MHz :
Nice to see that OY1OF on the Faroer Islands caught my signal.
I made some local FT-8 QSO's with PA2J, PH2M and PB75A as well.
Off topic:
Thursday, 10 December 2020
Clockgenerator
The Si5351 clockgenerator needs only 4 wires to connect to the ESP32 DEV board.
2 most left wires: I2C bus
Si5351 ESP32
SCL IO22
SDA IO21
GND GND
Vin 3V3
After uploading following Adafruit Si5351 example sketch, the clockgenerator generates 3 squarewaves of different frequencies:
Update 13 Dec 2020:
Clockgenerator with three dedicated output frequencies (144.060, 70.100 and 14.020 MHz) on veroboard. I used the Adafruit program 'Clockbuilder' to generate the parameters to be used in the sketch:
The signal of CLK0 output (144.060 MHz) being received on the UV-5R.
Off topic:
10 February 2021, Bommelsedijk, Zuidzijde
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