Review: MX-K2 keyer offers features, thrifty value …

Saturday, March 20, 2021

With my upstairs radio shack (I have dubbed “Studio C”), I’ve found myself surrounded by classic and vintage transceivers that have one thing in common; not one of them has a built-in CW keyer.

Right now I’m listening to a Ten-Tec Omni V, and its the most current radio I am operating. I’m surprised that a radio that was considered a high-end rig when it was released lacks a built-in CW keyer, but one must remember that Ten-Tec also had a full line of single paddle and iambic keyers for sale at the time.

But I also have a Tempo 2020 here in Studio C; a Kenwood TS-530S, and my pride and joy, a Hallicrafters SR-400 with the hard-to-find HA-20 outboard VFO. And that doesn’t include the rigs on the shelf I don’t have ready to operate, including a couple of Heathkit SB-102s; a Swan 500C; a Hallicrafters SR-150, and the Hallicrafters twins — the SX-117 and HT-44. And of course, none of them have built-in keyers.

Other than one IC and the 2 AAA cells, there’s not much inside the case of the MX-K2 keyer.

I have one of the low-end MFJ keyers, but I have mislaid it in the shuffle of moving gear in and out of the operating position. Being the thrifty (i.e., cheapskate) ham I am, I took to eBay to find an inexpensive keyer.

ENTER THE MX-K2 KEYER. While the price is initially what attracted me to the MX-K2, the keyer offers an impressive array of features, which include:

  • Two independent memories. The first is a 60 word memory that can be broken into segments; these segments can be replayed without playing the entire memory contents. This memory is saved in non-violatile memory.

    The second memory holds 50 words which can also be broken into segments. This memory is violatile, and its contents will be erased when power is removed from the keyer.
  • The keyer offers a command mode feature; unfortunately, the instructions for this feature are in poorly translated English, and I’m unable to try these commands on for size.
Jumpers on the board allow you to change the paddle configuration without changing your key’s wiring. J1 allows you to shut off the annoying-as-hell piezo buzzer. You’ll want to shut it off, trust me.

KEYS RIGS NEW & OLD. One feature I found attractive is that the keyer can work with any rig; the keyer operates a relay that is isolated from the rest of the circuitry, so it doesn’t really matter if there’s 90 vdc on the keyling line, the keyer takes its line to ground, and this will key just about any classic or modern transceiver.

The keyer is operated by two AAA batteries; the main PC board has a holder for the batteries. The keyer has no power button or switch; it goes to sleep after a period of not being used, but closing the keying line “wakes” it up.

The keyer is housed in an aluminum housing that is surprisingly stout. Remove the 4 tiny phillips head screws on the front of the unit and the entire thing slides out.

SCREECHY DITS & DAHS. The keyer comes with one of the most annoying piezo buzzers I’ve ever heard; one of the first things I did was to open the unit up and shut off the godawful screech by removing a jumper J1. The built-in buzzer is useful to test or adjust your keys, but otherwise it isn’t something you’ll want to make a habit of listening to.

The one feature you would think this keyer would have is the ability to deal with serial numbers for CW ops who contest. No such feature exists (or if it does, I’m unable to decipher the details from the instructions on the eBay listing). I’m not a big CW contester, so the serial number feature isn’t one I will miss.

I’ve only put the keyer to work for a couple of nights on my CW traffic net. I’m going to try out the memory feature in the coming nights; since my transmissions during the net are pretty much the same from night to night, I will use the memory locations to see how easy they are to work with.

I’m using the MX-K2 with a classic Brown Brothers BTL iambic paddle. The keyer doesn’t care what you use, of course.

MINOR COMPLAINT DEPARTMENT. In addition to the lack of a serial number feature, the keyer lacks a common keyer feature to make your paddle “semi-automatic”, which means you control the length of your dahs, not the keyer. It also lacks a “tune” feature, which keys the transceiver, useful for checking your antenna tuner settings (if the keyer has the “semi-automatic” feature, you can use that to key the rig as well.

The keyer is small — about 4 inches long, 2 inches wide and less than an inch high. The connections are stereo 3.5-inch for keyer and output to the rig on the rear panel; the front is dominated by a speed control knob. The front also has an LED that lets you know the keyer is keyed, and two momentary contact buttons for accessing the keyer’s memory features.

YEAH, BUT HOW MUCH?? As stated at the beginning, the keyer’s price caught my attention: as of this date, (March 20, 2021), the MX-K2 keyer is selling for $18 to $24 from eBay sellers in China. Add a couple of bucks for shipping, depending on the seller. Just be aware that most of these keyers are shipped by “SpeedPAK” from China, and I think the English translation of the word “SpeedPAK” is “on a slow boat from China.” Let’s just say you should be prepared to wait a few weeks.

You might want to order TWO of these keyers; keep one and give the other as a gift.

THE ZEDMAN SAYS … The MX-K2 keyer offers great value and features. It won’t replace your high-dollar contest keyer, but for the average operator it’ll work just fine.