JNCRadio's CS-818 tuner in the field test with Marco, DD6FM: Portable radio made easy!

Hello, my name is Marco, DD6FM and today I am testing the CS-818 Tuner from JNCRadio.

Equipment on bench

It's mid-September and the weather is still nice and warm today to do some portable radio. Normally I use mainly end-fed half-wave antennas with a 1:49 transformer, but there are often some situations where I want to cover more bands during my activations, then it makes sense to work with a tuner.

The configuration in detail

My configuration today looks like this:

I use a mast from Spiderbeam with 7 m length, on which I use a 7 m wire from DX Wire as a radiator.

Then comes a 1:9 UnUn from LDG and behind it a self-built jacket wave trap. A 13 m wire in this combination has proven itself as a radial. Next comes 10 m RG-58 and a Yaesu FT-818.

Operating the CS-818 Tuner
CS-818 Tuner

Now let's take a closer look at the tuner and the operation.

There are connections for the antenna, transceiver, an ACC interface, an external power supply and a charging socket for the built-in battery with USB-C at the back. You can therefore also operate the tuner without external power, which I prefer.

On the front, we see the on switch on the left, the display, the control buttons and the TUNE button on the right.

On the first page you can see the SWR and the output power.

On the second page we see the L/C network and on the third page the configuration.

Let's go ahead and connect the Yaesu to the tuner using the ACC cable provided. Then switch on both devices and go to the Yaesu configuration, menu 14, "CAT Rate" 38400. There is nothing more to do on the Yaesu. Of course, you can also use the tuner with other devices and manufacturers. In this case, it is best to use the AUTO mode.

Let's have a look at the configuration. There are 3 options in Mode:

AUTO In automatic mode, the CS-818 automatically starts tuning when transmitting if the SWR is above the threshold defined by the menu item "AUTO SWR". The tuner then tries to tune below the value set at STOP SWR. This value should not be too low, otherwise tuning may take longer.
FT817/818 Mode When using the ACC cable, simply press the TUNE button (reduce output power first if necessary), the YAESU will switch to PKT mode, send a carrier, tune and switch back, done.
Manual Mode In manual mode, you transmit a carrier (e.g. FM) and then press the Tune button.
MIN PWR The MIN PWR menu item determines the value in watts above which the tuner should start.
BRIGHTNESS The brightness is set here.
RESET here you can reset everything.

The unit is of excellent quality and makes a good overall impression.

The tuner in practice: Marco's experiences

Let's go, so we briefly looked in the SotA cluster to see who was offering to "hunt"...

LA1SOTA on 15 m. I use the ACC cable, so FT-818 on 15 m, briefly pressed the TUNE button, antenna was tuned to SWR 1:1.3. I got through on the first call and received a 55 from Norway as a report.

I was able to tune all bands from 40 m to 10 m without any problems.

Equipment on wooden table
Conclusion: The CS-818 Tuner - A reliable companion for portable radio activities

The little tuner did an excellent job that day. It is easy to use and what I like most is that it has a built-in battery. It does what a portable tuner is supposed to do without any problems.

Technical details and specifications

Finally, a few technical details:

RF power:

  • 0.5 - 30 watts SSB, CW;
  • 0.5 - 15 watts FM, AM and digital mode;
  • 1.8 - 54 MHz coverage (160 to 6 metres);
  • Tuning to 5 to 500 ohms (15 to 150 ohms for 1.8 - 3 MHz)
  • Fast tuning: 5 seconds typical for a new tuning, less than 1 second for a memory recall
  • Weight 510 g
  • 20000 memories for the Yaesu FT-817 / 818
  • Scope of delivery: tuner, CAT cable and USB-C cable
  • Size: 145 mm x 115 mm x 36 mm

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