28 April, 2023

3 tips for not blowing the finals of the QDX transceiver

I have now used both the low- and the high-band QDXes daily as EA8/LA3ZA for a period of two weeks without destroying the four BS170 final transistors. Here are some procedures and tips.

But first, I do actually have experience in blowing the finals. That happended under testing prior to leaving, and all it took was 9.5 Volts for my 9 V build and what I thought was a dummy load, but which might have been an open circuit load. One BS170 developed a short between drain and gate with the result that 9.5 Volts was passed directly into the outputs of the driver IC5, 74ACT08, so IC5 blew as well.

My three tips for avoiding such failures are:

18 April, 2023

Clock cycles through chemical elements

The latest addition to the Multi-face GPS Clock is a clock face that for hour, minute, and second cycles through the corresponding chemical element in the periodic table. This is shown in the image to the right.

This is screen number 39 for this clock, all of them selectable by rotating a rotary encoder. The project, with Arduino Mega hardware and software is documented on Github, where the current release is v.1.6.0 (2023-04-14).

The display also shows  the full name for the element corresponding to the second, as shown above for element 3 which is Lithium. It is located in group (column) 1 and period (row) 2.