Monday, 27 April 2020

50 MHz signals from India

When switching off my radio gear yesterday evening I was suprised to find a part of an FT-8 qso from India (QTH loc. JQ05) on my screen !

These were certainly the most distant 50 MHz ham radio signals I ever received:


QSO between VN4VUP and 8U8MBJ on the FT-8 screen.

What kind of propagation must this have been ? Multihop sporadic-E ?


Wednesday, 22 April 2020

Restoration PSU FP-4

With a rather simple circuit I was able to restore a Yaesu Power Supply Unit FP-4.

The PSU is almost 40 years old and the internal original circuitry was damaged. The transformer, diode bridge and 6800 uF capacitor were still ok.














I found this circuit to replace the existing electronics:


PSU circuitry


Soldered this small circuit on a vero board and installed it in the housing:

Restored PSU

Now the FP-4 PSU is up and running:


Note: PNP Power Transistor MJ2955 may be replaced by MJE2955, TIP2955 or 2N2955.



Sunday, 29 March 2020

4 m transverter

With the excellent designs of Serge, UT5JCW ( http://transverters-store.com/ ) I completed a 4m transverter:



The unit operates between 70 ... 72 MHz with IF (from my FT-450) between 28 ... 30 MHz. 

RF output power is appr. 10 Watts.


Although, I do not see much activity on the 4 m band, I spotted some stations operating in MSK144 on 70.175 MHz. Maybe that is something to focus on coming days.

Circuit diagram 28 <=> 70 MHz transverter

Transverter board

Update May 6, 2020 :


Update May 24, 2020 :

First FT8 4m QSO with the transverter over 24 km with PA3EWP.





Thursday, 12 March 2020

70 cm FT-8 contest

Yesterday evening I participated in a 70 cm FT-8 contest. A good opportunity to test my 28 MHz - 432 MHz transverter.
I was able to make a couple of QSO's (PA3BGQ, PC4L, 2E0NAQ..).


eQSL from PC4L


The QSO with 2E0NAQ over a distance of almost 200 km was very interesting:


70 cm FT-8 contacts March 11, 2020


PC4L, Marcel, sent me an e-mail showing that my signal showed some frequency drift of appr. 10..50 Hz. This is certainly an anomaly that needs to be fixed.

Off topic:


Tulip field near Den Bommel

Sunday, 2 February 2020

PA for 70 cm transverter

From BG7SGM, I ordered a PA module for 70 cm:
It is capable of delivering appr. 20 Watts RF at 70 cm. The module uses a M57704H.

I installed the module in the 28 - 432 MHz transverter:



A good heatsink is required. For the first time I used the repeater shift mode of the FT450. For 70 cm repeaters, in The Netherlands the repeater shift is 1.6 MHz. I also had to insert the CTCSS frequency of 88.5 Hz. I made a short QSO with PA0WBS via the Rotterdam repeater (430.300 MHz out). 


A quick measurement showed that the transverter delivered 15 Watts RF. Now, the challenge is to work in digimodes and see what is possible (FT-8 in particular).

See bg7sgm.taobao.com  and eBay for more RF products from BG7SGM (use google translate!).


Thursday, 9 January 2020

First FT-8 signals transmitted on 432 MHz

Yesterday I transmitted my first FT-8 signals on 432.176 MHz. PA3EWP received those signals:



At the moment of transmission the 28MHz-432MHz transverter delivered 2 Watts only.




Off-topic (1):


Collection of WO2 communication equipment in the 'Oorlog- en verzetsmuseum', Overloon.

Off-topic (2):


Garden Art

Monday, 6 January 2020

28 MHz - 432 MHz transverter

I started to work on a transverter that converts 28 MHz (10 m band) to 432 MHz (70 cm band). I use a FT450 to process the 28 MHz signals. At 432 MHz the transverter is capable of delivering about 5 Watts RF. A Power Supply Unit from an old PC was used for the 12V/12 Amp and 5V/20 Amp electrical power supply .




Frontview transverter


The transverter and control board I used were purchased in the Ukraine. See http://transverters-store.com/ and also ebay.


                                           Transverter board


Control board with 50 ohms/10 Watt load


First results are promising. I could listen to repeater signals in FM. I hope it will be possible to work with digimodes later on. I will consider adding a PA stage to increase the RF output (to 10..20 Watts).

Friday, 3 January 2020

Kilrock Radio

On Medium Wave I discovered 'Kilrock Radio'. 




They broadcast rock music from the '50-'80s. This is a small radio broadcast station located near Dordrecht. They transmit with 100 Watt RF power on 1287 kHz. I discovered that they can be received on my car radio receiver on various locations in Zeeland and Zuid-Holland. In the evening/night they are often 'overruled' by a Spanish station.

https://kilrock.nl/




Tuesday, 10 December 2019

Garden - Flora


Garden - Flora

In order to observe the changes through the seasons in my garden I intend to gather photo's here.

An overview from my garden:




1. Zomereik / Quercus Robur


May 2020


May 2020

2. Sneeuwbal / Vurbarnum Opulus


May 2020


May 2020

3. Vijver / Pond


May 2020, Gele Lis/Iris pseudacorus


17 May 2020

4. Grove den / Pinus sylvestris


May 2020

Dennenappels / Pinecones




5. Vijf

6. Esdoorn / Acer


May 2020


7. Winterharde palm / Trachycarpus fortunei


May 2020



May 2020

8. Acht

9. Negen

10. Perenboom




May 2020
11. Elf

12. Twaalf

13. Dertien

14. Ligusturhaag / Ligustrum Ovalifolium


May 2020

15. Vijftien

16. Zestien

17. Zeventien

18. Achttien

19. (Witte) trosroos / Rosa Maria Mathilda


May 2020

20. Buxus


May 2020



21. Kas / Greenhouse




May 2020
22. Tweeentwintig

23. Drieentwintig

24. Vierentwintig

25. Vijfentwintig

26. Kardinaalshoed / Euonymus fortunei 


May 2020


27. Zevenentwintig

28. Achtentwintig

29. Negenentwintig

30. Dertig

31. Eenendertig



Fibonnaci and Sunflowers

You can discover mathematics in the garden.

One takes a head of a sunflower, let it dry for a while and concentrates on the seeds and their arrangement.



The arrangement of spirals in the head of a sunflower appears to show Fibonnaci numbers:

Number of left hand oriented spirals: 55


Number of right hand oriented spirals: 34

The Fibonnaci Sequence is constructed with the formula F(n) = F(n-1) + F(n-2) and the beginning of the sequence is as follows:

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144..

Amazing that Fibonnaci numbers seem to appear in nature a lot.

If you divide 55 by 34, you get 1.617… which is very close to the number phi (golden ratio)