My journey with amateur radio and APRS: Why I will opt for the new TH-D75E

Ok, ok, the "O" in OM actually applies to me now. I'm a pensioner, have been involved in amateur radio for more than 50 years and have seen a few things come and go. One of the best things for me was and is APRS, the Automated Position Reporting System. As a consultant for image and text transmission (yes, that was the real name back then) in the DARC e.V., I was more or less directly involved in setting up the packet radio network of the time.

Imagine those exciting times: We already had some idea of computer networks, but no way of trying them out on a larger scale. Network technology was simply expensive. So the Packet Radio network came just in time. For the first time we could (had to!) deal with data protocols, had to learn what hop-to-hop vs. end-to-end acknowledge means, what special problems directional radio at 13 cm entails and much more. What is different or special about radio-based networks compared to wire-based networks. Super exciting!

At the same time (in the mid-1980s and early 1990s), GPS receivers became affordable. And so the combination of packet radio and position-based data soon emerged - the APRS system. Here, the user's own position is recorded via GPS, coded and sent out again via simple AFSK in packet radio. An extensive infrastructure in the packet radio network ensures that this data is visible on websites such as https://aprs.fi.

In addition to the self-developed modems for APRS, various manufacturers soon jumped on the APRS bandwagon, above all the company Kenwood. The TH-D7E handheld radio with built-in TNC and APRS capabilities was first launched in 1999. A revolution! This was followed in 2000 by the TM-D700, a dual-band mobile radio with built-in TNC, which enabled simultaneous APRS and phonetic operation on two different bands. A GPS antenna was connected externally. Devices such as the TH-D72 and TM-D710 were launched later, followed by the TH-D74 in 2016. Each with newer technology, more powerful navigation solutions (Glonass, Beidou and Galileo in addition to GPS), improved software, Bluetooth function and much more.

And I have owned every one of these devices! And I have rarely found a better playground for radio amateurs. Yes, it really is fun. I remember holidays where I sat in the car for hours in the best weather to understand and try out all the functions, much to my partner's dismay. And a Kenwood FM transceiver always accompanied me on all my journeys, either in the car or as a handheld radio. It was marvellous fun, and it worked with the utmost reliability. Yes, sure, the packet radio network has largely disappeared, but the APRS iGates have remained.

Supply crisis and the end of an era: the fate of the TH-D74 after the chip factory fire

And then suddenly a chip factory burned down in Japan (AKM in Nobeoka, JP, October 2020). Ok, dramatic, very bad thing, but does it affect us directly? Very significantly, as the amateur radio trade soon realised. After all, the burnt-down chip factory was one of the most important manufacturers of LSI chips for audio products. And the TH-D74 contains such a chip. The real problem, however, was that these chips are also installed in the audio systems of many cars. In a panic reaction, several car manufacturers bought up all the remaining stocks of these chips and offered and gave a lot of money for them. The supply chain crisis caused by Covid-19 led to further shortages. Unfortunately, there was nothing left for JVC-Kenwood's somewhat marginalised production. So the company had no choice but to discontinue the TH-D74 well ahead of its planned life. Very regrettable. Within a few weeks, all stocks were empty and this beautiful radio was no longer available. I literally bought the last of these radios from my employer WiMo.

Ekki Plicht, DF4OR
TH-D75E: A look at the new Kenwood successor and why I will buy it

And then came the announcement in spring 2023 that there would be a successor to Kenwood - the TH-D75! It was proudly presented in Dayton at HamVention, and a few weeks later we were able to see it in Europe at the trade fair in Friedrichshafen.

A successor to the TH-D74 - and with which new features? Well... it's not that much. A new digipeater function. D-Star Dual Watch, USB-C charging socket. Nice, but does that justify the price of almost €900? Wow, I can get around 45 Baofeng handheld radios for that. But do I want them all? I don't think so.

Yes, €880 is a lot of money for a radio that offers relatively few new features and has hardly changed on the outside. I can understand Kenwood, there were probably still large stocks of the display, the keypad and many other components that they wanted to use and not throw away.

Will I still buy the handheld radio? Definitely!

TH-D75E: Perfect technology for a lifelong hobby

I can afford a piece of jewellery like this when I retire. I'm a play child and enjoy perfect technology. Because that's what the TH-D75E is for me - well equipped, perfect for me. Kenwood's APRS products have been with me for most of my amateur radio life, and I don't want it to be any different when I retire. I'm also pleased that this renowned manufacturer is bringing new products onto the market again. And by all accounts, the TH-D75 will not be the last innovation we can look forward to from Kenwood.

Have fun, see you soon.

73

Ekki, DF4OR

TH-D75E

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