Tuesday, May 18, 2021

Kenwood TH-D72A

I bought the Kenwood TH-D72A on the suggestion of a local mentor that is helping me to learn to work satellites and from Don Arnold who makes supportive videos for the TH-D72A and the newer model, TH-D74. The D72A is a full duplex radio whereas the D74 is not. Duplex meaning I can listen on one band and transmit on another simultainiously. The ISS changes protocols every couple of months and at this time, it is transmitting voice through its repeater with cross band operations. The uplink (from earth to ISS) is on 2m while the downlink (ISS to earth) is on 440. Working satellites takes a full duplex radio so it was an easy decision to get a full duplex radio.

I don’t usually buy used, I don’t want to have to deal with problems of wear and tear before I start to use it but these radios are expensive. I found one for less than $300 with all the accessories that I needed but it turns out that the person that sold it to me misrepresented the condition of the radio. Its fine the way it is but the buttons are worn through, the volume knob is loose and it was scratched as well as missing the speaker mic rubber cover. I found a place to replace the parts, ordered them and cleaned up the complete kit and polished the little window.

I’m all set.

I bought a Nifty manual for it as I find them satisfactory and they cut to the chase. I configured the full duplex cross band for ISS operations and my phone alerted me to a good ISS pass. I had four minutes to get ready and got the tripod/iphone/time-lapse going, the Arrow yagi connected and spotted the ISS. But I forgot to add the 440 elements on the yagi antenna! I was doing APRS through the ISS on 2m which does not need the 440 elements so I took them off to make the Arrow lighter and easier on the wrist.

I wasn’t ready!

So I pulled it off the BNC connector and put on the Diamond 77 and my first use of the TH-D72 was with the ISS. I could hear many people talking from all over. There was a Japan and USA conversation going on and I tried to make contact but it was so busy and I’m really slow with phonetics. My wife told me, “just listen.”

So that’s what I did.

My entry about the D72 is not about the radio itself, this is about my story and how I use it. There are plenty of resources including the manual which can be looked at for free from the Kenwood support site.

I really like the radio and I can see myself learning to work satellites with it.