Kachina 505DSP

The Kachina 505DSP was an early HF radio that utilized DSP for the IF <-> audio stages. The other unusual thing about is there is no built-in display. It is instead controlled via a PC over a serial port. I came across this on Facebook marketplace for a deal I couldn't resist. It was just the main box, no cabling or the control box. Over time I came across a control box and built up the cables from scratch. I learned a couple of lessons the hard way:

• The cable between the radio and control box uses a 15 pin connector, same as a VGA cable. The fellow I got the control box from sent a VGA cable along with it and I used it without realizing that in a VGA cable, some of the pins are effectively shorted together internally due to them being shields. This caused the serial comm lines to get shorted out and prevented control of the radio. The solution is to make your own cable, don't use a VGA cable!

• The audio level needed to drive it with a PC (to run digital modes) is much higher than other transceivers. You need at least 2V pk-pk.

It's a fun radio to play with and seems to perform very well. I still do not have a mic for it so I am using it exclusively on digital modes.

KCAT Control Software

I am using W1HKJ's excellent kcat software to control it. The original software only runs on windows XP so this is really a great utility as it runs on modern windows or linux (I run it on ubuntu). For linux, you have to build it from source. This was quite easy however and as I recall, worked out of the box with maybe one missing dependency, resolved with an apt package install. However, I did notice it consuming an entire CPU core anytime it's running.

I traced this down to the cw thread, which sends characters via CW from a dialog box. I added that highlighted line as without that, the thread never willingly yields in the normal case of not using this CW feature ;)