SA2CLC radio stuff

 I needed a couple bluetooth devices for varius audio projects. One was a music stream point in my 1958 Plymouth, but the catch was that I wanted it to have a custom name. Instead of something like "Bluetooth Device" I wanted it to say "58 Plymouth" or whatever I needed it to be. And, I wanted it permanent in place, installed inside the original radio, no external buttons and absolutely no announcements. After some research I ordered 5 modules almost for free from Aliexpress and set to work. They are called KCX_BT_Emitter Bluetooth 5.3. They are supposed to work with AT commands and serial communication, but I could not get it to work following online advice. I first tried connecting the modules using an Arduino Nano as a serial bridge, but that did not work, possibly due to the Nano using SoftwareSerial. I then switched to an Arduino Mega. using hardware serial (D18 D19) and a minimal sketch, I got it to work, but not the way I expected, but in the end I got it to ...

 I wanted full QSK in the big amplifier. QSK, also known as full break-in, allows the transmit/receive switching system to operate fast enough that you can hear between the dits and dahs while sending CW. Once you get used to it, it is difficult to go back to conventional semi break-in operation. Achieving full QSK requires very fast relays and, in many cases, a sequencer to ensure that all relays have settled before RF is applied. To find out what would work, I measured a large number of relays that I had available and compared their switching times. The goal was to determine which relays were fast enough for reliable QSK service. Below is the result. One thing worth noting is that relay speed can often be improved by driving the relay coil with a higher voltage than its nominal rating. This is a commonly accepted practice, provided that a suitable current-limiting resistor is placed in series with the coil. Relays tested. Interesting was that Omron G2-RL relays was very fast with...