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Short Takes #17: New Mercury ATS Tuner

By Dave Jensen, W7DGJ

In December of 2022, for Trials and Errors Issue #4, I reviewed a new automatic tuner from KM3KM Electronics, the designer/developer for the popular Mercury IIIS and Mercury LUX linear amplifiers. The Mercury AT tuner performed very well under a variety of conditions in my shack, and I was pleased to be offered the opportunity to get an early glimpse of the new KM3KM tuner just introduced, the Mercury ATS, which will replace the AT in their product mix.

I've reviewed the KM3KM linear amplifiers in this column as well. They're quite unusual -- built to last -- and while they don't always feature every single element that fussy amateurs look for, no one would deny that a company that has sold this many amplifiers deserves the serious attention of the marketplace. The customer base for KM3KM Electronics is almost rabid in its ferocity when supporting this brand (read the eHam reviews). This meant that when the company decided to add tuners to the lineup there was a pent-up demand.

In an earlier in-depth exchange with Kenny Martinez (KM3KM), I wrote that Kenny will be an important part of the future of amateur radio. He's still a young guy, and his designs of today could very well be in use by future hams collecting the "classics" 20-30 years from now. But I also noticed something about Kenny in that exchange. Like many creative types, he is a stubborn man who knows what he wants to build and he will not be swayed by competitive products or by ideas that he doesn't necessarily buy into. Even those ideas that might increase his company's sales. Believe me, there are some issues of marketing or of product features that I've attempted to get across to KM3KM that will never go anywhere as they conflict with Kenny's core beliefs.

Martinez is resolute on certain elements of his designs (and of the marketing of those designs) in a way that I've not seen from other entrepreneurs. In this intro for the Mercury ATS tuner, which I have beat up over the last ten days, I'll mention two of Kenny's philosophies about ham products. Without that explanation, it's impossible to position the ATS (or any Mercury product) correctly in the marketplace.

The New Automatic Tuner - Mercury ATS

When the folks at KM3KM Electronics introduced the Mercury LUX amplifier, it was clear that there would shortly be a need for a full legal limit tuner. The power output of the LUX goes comfortably past the USA legal limit of 1500w, and the original tuner, the Mercury AT, is rated only for their lower-powered amplifier, the highly regarded Mercury IIIS at 1200w. Users of the LUX amp who needed a tuner could either back down on the full legal output and use the AT, or go with a competitive product like the MFJ-998 ($769) or the Palstar HF-Auto ($1650), both good products but not the choice of many who wanted to maintain the look and feel of their Mercury amp. 

It's here that I'll mention one of Kenny Martinez's design philosophies -- one that he'll always hang his hat on. He's not a fan of memories. For companies (like the two mentioned above) who make competitive tuners that include memories, far less time is required to design that amp; the algorithmn used isn't critical because once an acceptable tuning point is reached for a frequency, it goes into memory. But Martinez wondered, what would happen if instead of relying on memories, we actually spent the time to improve the algorithmn in such a way that you could get a "fresh tune" in nearly the same time it takes to pull up a memory? He believes, and I'm convinced he's right, that's a far better solution. SWR can change. Using a tune from a frigid Winter's morning on a warm Summer day doesn't make a lot of sense; the environment is just one aspect of how SWR can change from day-to-day.

The Mercury ATS and my ICOM cable for the tuner allows me to operate with a one-button tune on the ICOM transceiver with about 1-2 seconds delay for that tune, depending on which frequency I am on. My antenna of choice for this article was a 135' OCF dipole where my SWR ranges from 1.8:1 to 4:1 depending upon frequency. For a really difficult tune, 15 meters on that 20-40m primary use antenna means that 15m is unusable, with more than a 7:1 SWR. In that case, the Mercury ATS takes a full 3-4 seconds. I can't imagine that this still relatively short tune would give anyone a hangup, even in a contest situation. I have other tuners in my shack (those with "memories") and the grinding/clicking sounds I would get in moving a 7:1 ratio down to a usable 1.2 to 1 would be nasty and annoying, and probably 20 seconds or more in duration. 

Which brings me to a second of Kenny Martinez's many stubborn aspects of design and marketing -- the specifications themselves. Kenny is an ultra-conservative engineer when rating a piece of gear. The Mercury ATS is rated at 5:1 maximum SWR matching. If that's the case, why does it tune my 15m band so efficiently? This new, full legal-limit tuner is rated at 1500w for SSB, but only a Kilowatt for CW. And yet, I've sat there at my desk pounding code afternoon after afternoon at 1300+w. The tuner doesn't even get warm. How could this be, if I am so carelessly breaking the "rules" of operating this new Mercury ATS tuner?

The answer lies in Kenny Martinez's views on specs. Despite what his marketing guy tells him, or product reviewers like me or the YouTube guys, he's not going to let his designs get victimized by "spec inflation."

Spec inflation is what happens when products move from engineering and design into the arms of the marketing and sales department at larger companies. I've witnessed it personally, as I spent many years working for a well-known company in the consumer electronics industry (and in the microphone business). I watched as our colleagues in design would turn their products over to the sales department. Stereo amplifiers that were rated by their designers at 200 watts per channel would go on the market at 250w per channel. Microphones would see their frequency response curve suddenly boosted at the high end instead of the dip that the engineers knew was there (but hidden in the original engineering specs). It's completely normal for manufacturers to push their stated specifications to the absolute edge -- and sadly, for some, a bit beyond.

Recently, I read the response from one highly-regarded antenna manufacturer whose impedance matching unit had fried when operated by a user at the exact level specified as "maximum" in their marketing literature. Their response to him, reflected in an eHam review, warned that operating at the maximum level was dangerous to their equipment.

But why should that be the case? If an antenna, or tuner, is rated for a Kilowatt but melts down at 1000 watts, is that right? Not according to Martinez. There is, literally, no other ham radio products company that I know of which has this same attitude about the specs. It's a part of the engineer's design philosophy, and when you look at a new piece of Mercury gear (as in the Mercury ATS) you must consider that in the equation

Mercury ATS Specifications

Operating Bands 160m – 6m
5-inch Color Touch Screen
Selection for 3 Antennas
1-30 MHz 1500 watts SSB
1-30 MHz 1000 watts CW
1-30 MHz 700 watts DIGI mode
50 MHz 300 watts
Inductance 6.3 uH / Capacitance 1100 pF
Matching Range 5:1
W 8 x L 10 x H 5.5 / Weigh 7.5 pounds

The ATS in Action

As you'll see, the appearance (and cost, at $850) of the Mercury ATS is much like the Mercury AT, as it is sized in the same case (with a nice powder coating) with both the front and back panels looking much the same. It was initially disappointing when I saw that my new "LUX tuner" had essentially the same format as the original AT. I was expecting that it might be bigger, heavier, and perhaps designed around the LUX with two massive handles on the front panel. But as I see it now, that wasn't the engineer's goal. Martinez wanted to make the best tuner possible, keep the price reasonable, and have it universally acceptable for all rigs and not just as a mate to the LUX. This is no "LUX tuner." Instead, it's one of the top automatic tuners on the market if you want to fine-tune your antenna system for legal limit.

But, there have indeed been significant changes inside. Those changes lie in the way that the capacitors are used and in its power handling; the algorithmn addresses the need for power across more capacitors than previously. I didn't think that KM3KM could improve the speed and accuracy of the resulting tunes from the level they had achieved with the original tuner, but they have. It's faster, it provides better end results, and it appears to me to be a better match for many scenarios. Still, KM3KM hasn't designed this one for you to attach to your gutters or cattle fence. Nope -- no long wires or unbalanced loads, either. This is another Kenny Martinez design philosophy that will always impact tuners coming out of KM3KM . . . "There is no substitute for a resonant antenna," as Martinez once told me in an email. Despite that comment, I can tell you that an ATS in your shack will certainly finesse your antenna into a much more manageable extension of your station, that's for sure!

The Comet CAA-500 MarkII Meter

Recently I was on an outdoors adventure with my gear and took a short detour to the restroom, leaving my radio and gear on the park table. I was only gone a minute, but in that period of time I managed to have my antenna analyzer stolen. I lost a very nice Rig Expert AA-55 Zoom, which I've used here on Trials and Errors when writing up antennas. I contacted one of the big three ham radio suppliers and bought another one, this time upgrading to the AA-230 Zoom. Unfortunately, when it arrived it was defective, failing its own self-test. There was also a cosmetic issue that bothered me, a plastic battery cover on the back that was bulging out. After the self-test failure, I opted for a refund instead of an exchange or repair. That's when a nightmare of back-and-forth began with the dealer (see my final note below). 

While I was going through the process of getting what would be an eventual refund, a friend of mine shipped me over a COMET analyzer, the CAA-500 Mark II. I bought it, of course, because once you have it in your hands, you realize that few ham radio accessories are built this well.

This unit has been in the market a number of years and it really doesn't offer all the same tests that the Rig Expert or other "antenna analyzers" might offer, but 99% of what I do is to determine impedance and SWR on the cables and antenna systems I am reviewing. So, it was perfect for me. It has a history of success (read the eHam reviews), a built in trickle charger for NiMh batteries, both analog and digital metering, and more. I'm impressed when products are this well made . . . it reminds me of a Chameleon product, or my Palomar Engineers OCF Dipole, and other products rated A+ here on T&E. If you've never compared the COMET to what you are using now, consider taking a closer look. 



Finally, as I close out this Short Takes (which hasn't really been all that short), I'd like to ask for your experiences with dealers on the return of products after a purchase. Please jump into the forum discussion below and let me know what your experience has been with defective products and their return. I had to pull strings (using the "I'm a reviewer" card) to get my refund processed. It was clear cut, with a "self-testing function" built into the analyzer that failed on day one. So, arranging a return and refund would seem to me to be a cake walk. But I was dealing with their engineering guys, getting emails about their cost of labor, things that I supposedly did wrong in performing the self-test, and so on. I had to produce a video to show them that it was, indeed, failing.

Do our major dealers do what they promise when they offer a return privilege? Tell me about your experiences, as I feel this is worth a future discussion.

73 for now,


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Dave Jensen, W7DGJ

Dave Jensen, W7DGJ, was first licensed in 1966. Originally WN7VDY (and later WA7VDY), Dave operated on 40 and 80 meter CW with a shack that consisted primarily of Heathkit equipment. Dave loved radio so much he went off to college to study broadcasting and came out with a BS in Communications from Ohio University (Athens, OH). He worked his way through a number of audio electronics companies after graduation, including the professional microphone business for Audio-Technica.  He was later licensed as W7DGJ out of Scottsdale, Arizona, where he ran an executive recruitment practice (CareerTrax Inc.) for several decades. Jensen has published articles in magazines dealing with science and engineering. His column “Tooling Up” ran for 20 years in the website of the leading science journal, SCIENCE, and his column called “Managing Your Career” continues to be a popular read each month for the Pharmaceutical and Household Products industries in two journals published by Rodman Publishing.

Articles Written by Dave Jensen, W7DGJ

This page was last updated August 31, 2023 18:30