Yaesu Interfaces

Posted on Wednesday, July 3rd, 2013 at 4:21 pm in

Audio board

Audio board

OM Doug Defty ZS1DUG from the Cape asked me what software and hardware I use to interface my Yaesu FT-857D and this is the reply I sent him:

Hello Doug, hows the Cape!

Lets tackle the software first: I started using Ham Radio Deluxe as my main package this past weekend. The main reason is the handling of the logbook. I want to start collecting some awards, and it feels like HRD is going to do it for me. However I played with many packages before making a decision: fldigi, DXLab and a few others. To be honest, I’m keeping all of them on my laptop because each one does something special that I like. What I am saying is, my contest logbook is from now on going to be on HRD. The rest is for playing. DXLab had a very easy way to monitor HF beacons, which I loved. fldigi on the other hand was great to sort out my cables with and watch the waterfall display. There are other nice programs too, you should try them all and keep the one that works for you.

The hardware followed an equally diverse route. I have two radios (FT-857D and FT-840) and thus I needed two setups. Eventually I realised it was over the top to build so many cables, but I like experimenting. Now, you need two cables per radio: 1= audio, 2=radio control.

(1) The audio to and from the radio into your PC can easily become contaminated with RF and hum loops, therefore you need to isolate the signals with small audio transformers. I bought one board from Jaco ZS6PX and it was almost identical to the one I bought from Phillip ZS6PVT, Essentially it is a matchbox-sized device with two isolation transformers and a capacitor/resistor or two. The transformers we buy from Communica for a few rands, see my picture attached. This one also has a PTT circuit onboard, but of course the Yaesu can PTT through the CAT cable and I don’t use the PTT on my radio. Total cost for an audio interface is R50 or so if you build it yourself.

(2) The radio-control cable (CAT in Yaesu language) is a little more complicated, although not terribly so. I am going to include a HRD manual for your perusal that I found on the internet and it has a few diagrams. You have to do level-shifting from 0-5volt to +/- 12volt. The hardest part is finding a board to simplify your construction. Basically there are 2 ways to interface: you either use a MAX232 chip, or you use a few transistors. I’ve tried both and they work. I even built the “tini-cat” circuit diagram that I found on the internet. Notice though the generous use of little ferrite rings everywhere to kill RF interference. The photo shows the board I purchased from Jaco ZS6PX (transistors) and Phillip ZS6PVT makes a chip one. Both work very well. Built-up they can cost you a little bit, but if you are handy with a soldering iron you can do it yourself. My first one I built for nothing, stripping an old CB radio for parts!

RS232 board

RS232 board

NB NOTE: Just remember, the boards you build yourself are Serial (RS232) interfaces. Modern computers don’t have serial ports any more, so you should have an additional USB-to-Serial converter cable handy. This adds around R100 to your budget if you have to buy it.

(3) While we are on the topic of expanding your radio, I want to mention that I also built an external S-Meter for my 857, the hardest part was to print the new scale to stick onto the existing dial.

(4) My final add-on is a small board that I bought from Vivian ZS6VD. You plug it into your mic cable, and you use a PC Headset as a mic-and-headset combination. Quality very good and it took me an hour to build. Now I can operate silently at night while the family is asleep..

Doug, I was ecstatic when I was first able to control my rig from my PC, and so I wish you luck with your project. Don’t hesitate to contact me for more info. I’m putting this email on my website also.