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 March 2021

2 March 2021

26 June 2017

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:


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.

Deltares has published a nice graph showing the sea level trend.

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).

                                    Oude Tonge, 1 February 1953

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:

10 Feb 2021 ; 

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:

                                Goedereede, January 2021

Thursday, 10 December 2020


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:

Here you can see the signal of clockoutput #1 (13.55311 MHz) being received by my FT450:

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

Saturday, 5 December 2020


 I found this nice gadget. It is a signal generator and contains a Si5351 integrated circuit. Should be able to deliver signals in the range from 8 kHz till 160 MHz.

Hope to get it working with the ESP32 module.

Adafruit provides a program called 'Clockbuilder'. This program calculates the parameters to generate your own set of frequencies.

Friday, 13 November 2020

ESP32 Simple Wifi server

I am exploring the Wifi possibilities of the ESP32 module. 

I found a sketch that enables you to switch on/off a LED via the module through an internet browser. I selected pin 2 as output, since this pin is connected to the internal blue LED of the module.

The LEDs on the ESP32 DEV module

The sketch includes the 'wifi.h' subroutine that sets up a steady wifi link to your local network.

I adapted the sketch and included two counters that shows you the number of switch on/off actions in your browser.

So now I have two-direction data traffic from the ESP32 mini wifi server to the internet browser. It works fine.

Part of the sketch:

This is how it looks like in the browser:

I am impressed by the Wifi capabilities of the small 3$ device.

Update 21 Nov 2020;

I added this Wifi functionality to the CO2 analyser (see also blog 4 Nov 2020).

Update 5 Dec 2020;

CO2 Analyser housed

Wednesday, 4 November 2020

ESP32 lessons

Past days I learned a lot about the ESP32 microcontroller. Internet taught me how to connect an LCD to the controller and how to read analog inputs.

I installed the Arduino IDE with the Espressif files to be able to program the ESP32 development kit in "C".

At this moment I have a working prototype of a CO2 sensor circuit. I used an MG-812, CO2 sensor.

This is how the setup looks now:

CO2 sensor setup

The circuit consists of an analogue and digital part:

CO2 sensor analogue circuit with 10x gain opamp

CO2 sensor digital circuit

This is my first program in "C":

It was an interesting voyage to get the module in action. Lots of features are there to be discovered; wifi and bluetooth function, I2C protocol, PWM outputs etc.


-The electrolytic capacitor of 10 uF between EN and GND on the ESP32 module was necessary to upload the program to the module. It took me a couple of days to find that out.

-The max input voltage of the ADC inputs is 3.3 V. That's why I installed a 3V3 zenerdiode after the output of the opamp.

Update 21 Nov 2020:

I added the wifi functionality to the software. I can read out the CO2 concentration via the internet:

Also placed the ESP32 module onto the board:

Updated 5 Dec 2020;


Sunday, 25 October 2020

Internet of Things

I read some interesting stories about the IoT lately. The ESP32 development board turns out to be good starting point to do some experiments with Wifi, Bluetooth etc.

I ordered a couple of this interesting, low priced, devices.

Time to get familiair with the Arduino IDE and the C programming language.

Off topic:

Krammerdam, 8-nov-2020

Krammer, January 2021