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 ?


Off topic:



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.