Bringing Modern Control To An Old Radio

The modern ham radio shack can take many forms. Some are shrines the “boat anchor” radios of old, named for their considerable weight. Others are simply a small, unassuming software-defined radio (SDR) hooked up to a laptop. Nowadays, many shacks fall somewhere in the middle. It’s not uncommon to find a sleek Icom IC-7300 sitting atop an ancient Hallicrafters SX-115 (which sounds suspiciously like the author’s setup). When a ham wants to work a digital mode such as FT-8, they will undoubtedly reach for a newer radio complete with USB (Universal Serial Bus in this case, not Upper Sideband) rig control — but what if the newest piece of equipment they have is a thirty-year-old Kenwood?

If that sounds like you, then fear not because [Steve Bossert] has you covered. He took his trusty Kenwood TS-50, a classic radio from 1993 whose most advanced feature is fuzzy logic, and upgraded it with USB (again, the serial bus) control.

When Kenwood designed the TS-50, they had computer control in mind. There’s a hidden port on the bottom of the unit which reveals a connector that mates with Kenwood’s proprietary (and expensive) set of serial control cables. Thankfully, the engineers over at Kenwood decided to use UART for PC communication, so slapping a USB port in the radio’s case isn’t as daunting as it may sound. [Steve] picked up a CP2104 USB-TTL UART Serial Adapter and wired it up to the radio’s control port. After a bit of drilling, screwing, and gluing, the radio had an upgraded (and non-proprietary!) interface compatible with the ever-popular hamlib. While this doesn’t cover all radio control functions, it gets you tuning, which is pretty important. For a fully modern radio experience, [Steve] suggests using the 8-pin mic connector along with an interface such as Rigblaster or Signalink. This adds PTT and audio signal routing.

If you want to try this for yourself, be sure to check out [Steve]’s extremely well-documented writeup. You could even take this a step further and control your TS-50 from your smartphone with this HTML5 interface we saw a few months back.

12 thoughts on “Bringing Modern Control To An Old Radio

  1. “There’s a hidden port on the bottom of the unit which reveals a connector that mates with Kenwood’s proprietary (and expensive) set of serial control cables.”

    Reminds when I had to get a cable for my PLC work.

    1. What are Tubes ?, The good old days of HEATHKIT like my SB-303.I Miss RadioShack like everyone. The RadioShack on the web does not come close to what it was … QRT,73’s everyone.

  2. The TS-50 is by far one of the most reliable Hf radios ive owned ,fielded,serviced and installed,
    installed them in Fishing boats, countless mobile installs (i have 3 one in each of my vehicles Along the MAT-100 ATU and a 102 inch whip) and even a helicopter install for a Aerospatiale Cougar helicopter. after owning countless HF rigs , i cant seem to find a radios that is rugged enough to handle the temperatures of both Antartica and the Atacama dessert without problems.

    Still cant find a radio that has that form factor and level of reliability that the TS-50 has , not even the Icom IC-7300 with its known 3.3v rail problems or the noisy FT-857 or the Dx-7 from Alinco that melts and cracks under the atacama heat.

    Adding cat to it just takes it to the 21st century…

    1. didn’t the ts50 have issues with the custom dds chips dying and replacements not to be got anywhere, and the guy i sold my old one to just got it back from a repair shop after the leaky capacitors did a huge amount of damage.

      1. Not sure if it also applies to the TS-50 but that’s definitely an issue with the Kenwood TS-850S. I got one at a hamfest a few years back and the original owner said he had to replace the freq synth ICs with a fixed revision after just a few years of owning it. It’s worked great for me otherwise, really nice radio and came with an IF-232 for CAT control and full service manuals and service history.

      2. never saw the DDS failure , but did a bunch of recapping on kenwoods, as i write this message theres a TS430 on my bench waiting to be recapped because the RIT went nuts, as radios age , this problems appear , good thing is that we are not just appliance operators and we can still fix our radios, with smd takes more equipment , but you gotta do it anyway, its a core part of our hobby.

        1. I’m sure that regular maintenance and -most important- timely recapping is what keeps your radios going strong. Maybe what kills those DDS chips are the nasty effects of high ESR over time… kinda like Tektronix gear and their propietary IC modules dying ’cause of leaky caps, and B+ rails going over the roof.

  3. The CAT port isn’t a secret. Its easily accessible via the rubber plug on the bottom of the radio.
    I bought a plug for the CAT port several years ago, and just made a cable with an inline USB to serial adapter and plugged it directly into the socket.

    IMO butchering the side panel to fit the USB socket makes a real mess of the radio and is not the ideal location.

    There is space on the back panel to fit a USB socket, but you have to substantially dismantle the radio to fit a socket in that location. However I didn’t want to take the radio that far apart.

  4. Any love here for Icom’s CI-V digital control system?

    I have an IC-735 and a R7000, and they both have CI-V.

    It is really quite elegant, implementing a true serial bus structure, not just a serial port.

    I once made an interface to a parallel port, from which I controlled these radios from a Tektronix workstation, using Smalltalk, but that’s long gone.

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