I bought my Yaesu ATAS-120A in 2007 after upgrading to a General Class Amateur Radio license. Being new to the HF bands at the time and operating while mobile, I wanted a multi-band antenna that was affordable and easy to use, yet still effective. “Easy to remove” was also on my requirements list since my weekday commute included a parking structure. “Affordability” is subjective, but I think its pricing was similar to that of its competition… and it still is today! However, the ATAS-120A, shortened to “ATAS” from here onward, was and continues to be in a class of its own since it doesn’t use external control wires or require a separate tuner. Simply screw it onto a bonded SO-239 mount, connect the feed line to a compatible Yaesu transceiver, and then press the “TUNE” button… the rest is automatic. It doesn’t get any easier to use than that!
Is it effective? That may be subjective, too! I was making contacts and getting good signal reports, which some say is not enough to prove that the ATAS is a good antenna. Making contacts to both Europe and South America seemed “effective” to me! I even made a weak contact to Hawaii from the deck of a car ferry on the Delaware Bay! Could my signal have been better? I suspect it could, but the ATAS was getting the job done for this beginner! This photo shows my ATAS mounted to a Diamond K9000 motorized antenna mount that enables me to lower the antenna at highway speeds or when entering height-restricted areas.
The ATAS has been both praised and criticized over its lifecycle. Those who love it appreciate its ease of use while some critics say that it’s “just a tunable dummy load” and that nearly anything else is better. Calling it a dummy load is an exaggeration, but is “nearly anything else” better? That may be true with the assumption that there’s plenty of space to mount said better antenna. I’ve always driven small cars; so, real estate is at a premium. Apartment dwellers also have mounting restrictions; and home owner’s associations are almost unavoidable near cities, especially in newer developments. As a result, there’s something attractive about employing smaller multi-band antennas.
By way of comparison, I bought a Scorpion SA-680 mobile HF antenna in 2020. I had to see if “bigger is better.” 😉 The Scorpion is a great antenna, but isn’t nearly as convenient to mount or use as the ATAS! There’s nothing automatic about using the Scorpion or nearly any other screwdriver antenna, not without spending even more money to add an external controller. But its main drawback in my application is that it blocks access to the hatchback. The ATAS clearly wins the convenience and accessibility categories. But how does it compare to the Scorpion? I’ll share a comparison in a separate article later.
Why does my 2007 ATAS-120A now Rest in Pieces, R.I.P? It’s my fault! Yaesu’s only published power rating for the ATAS is “120 watts A3J.” In short, “A3J” is Single-Sideband (SSB) mode. That seems great when considering that most HF transceivers output 100W. However, if you look at the specs for some other screwdriver antennas, you’ll see that their ratings for AM, FM, and data are ~25% of their SSB power ratings. I usually operate at 50W in FT8, but I don’t think that alone is what caused the demise of my ATAS.
I’m learning Winlink, Vara HF, and similar programs. I missed a setting in Vara HF and allowed the radio to transmit in USB instead of USB-Digital. Why was that a problem? I configured my FT-891 to transmit at 100W SSB, 5W AM for tuning, and 50W for all other modes as a way to automate some settings. As a result, my Winlink session happened at 100 watts without me realizing it soon enough! The same mistake in FT8 mode would have resulted in 100W output for 15 seconds followed by 15 seconds of receiving. A Winlink session, on the other hand, can call for extended transmission sessions to send a message. Unfortunately, I was multi-tasking during a Winlink session. There came a point when I looked at my radio and noticed that the SWR had climbed a bit. “That’s weird!”, I thought. I fine-tuned the ATAS to bring SWR back to a match.
It didn’t take long for the SWR to climb again. That’s when I realized my error! I aborted the Winlink session and began to investigate. I did a series of tests and concluded that everything worked except for on 40m, the band that I had been using. I speculated that I might have opened a coil winding in the lower end of the coil, an area that’s bypassed at higher frequencies. I had a VHF contest approaching and other distractions; so, I procrastinated disassembling my ATAS for internal inspection. Again, the antenna worked fine at frequencies above 10MHz. Plus, I still had the Scorpion available for 40m, 60m, and 80m. So, I carried on.
About six months later, I was cleaning the ATAS when the outer tube separated from the top cover. “OOPS!” I saw glue stains on the tube and figured that I could just reglue it. I looked into the top of the tube and saw what I thought might be the remains of insects that had made their way into the antenna and then could not escape. That’s when a terrible smell from inside reminded me of the incident on 40m. It was a nice day to figure out how to disassemble my ATAS for deeper inspection. I disassembled it in accordance with online instructions.
The first thing that I noticed, other than the strong smell of “magic smoke” that had escaped, was the definite charring of the coil bobbin. I looked for an open wire along the coil as I slid the guide ring up so that I could see more. That’s when it became clear that the lower end of the coil bobbin had melted. It was swollen and deformed to the point of shifting as it attempted to slip through the guide when the antenna extended toward 40m. However, the antenna was physically incapable of extending beyond the 30m mark. Remember, the antenna worked fine at frequencies above 10MHz. Still, would anyone really want to reassemble this mess and put it back into service? Should I repair or replace the antenna?
Reflecting back on the splatter inside the tube (photo above), I concluded that if the coil bobbin exploded outward onto the tube, then it probably exploded inward onto the threaded drive rod, bearings, guides, and other small bits inside, too. Yes, it can probably be cleaned, but I was more inclined to replace the antenna with a new ATAS. “WHAT? Why not get a better antenna?” I was VERY tempted by some of Tarheel Designs‘ antennas. Their smallest antenna, the Little Pro, is only $200 more than the ATAS, but the additional accessories needed to mount it and adapt it for my use quickly added to the price tag. Regardless, I already have a better antenna with the Scorpion. I still wanted a convenient antenna for daily or short-notice use that works on 6-40m and is not too heavy to ride on a K9000 mount. Nothing beats the ATAS for that, especially at its price! Technically, the ATAS weight exceeds the weight capacity of the K9000, but the mount still seems strong enough to work sufficiently.
Brand new and free of bug splatter… for now!
I tolerated being without full-time HF capability for about two months to see if Yaesu would have a sale that coincided with Hamvention. No luck there, but Ham Radio Outlet had an open box item that was $40 below retail and included free shipping. I ordered it during Hamvention. The new ATAS-120A mounted effortlessly in place of the old antenna and initialized without issue almost immediately! The car is back to “normal.” As a precaution, I have reduced my transmitter’s output power on digital modes to 30 watts and will perform future Winlink operations only with the Scorpion antenna.
Are there better antennas and better mounting solutions than what I have here? YES! But that’s not the point! The ATAS gets me on most HF bands while still being able to squeeze into parking structures and other height-restricted areas without the need to stop and store the antenna. Not wanting to stop sounds lazy, but the truth is that I sometimes don’t know that I’m going to enter a height-restricted area; plus, it’s not always possible to stop and remove an antenna without being a nuisance to other drivers. An ATAS mounted to a K9000 mount mitigates the vast majority of surprises… I like that!
The Scorpion is a great antenna, but it’s not always practical, especially if I’m carrying cargo or need a shorter load. I leave it at home when I’m on those kinds of voyages. The ATAS fills most of my HF needs for one simple reason, using an adaptation from another saying: “The best mobile HF antenna is the one that you always have and will carry.” I’ll continue to use the ATAS for impulse opportunities and the Scorpion for planned events when I want a little better performance.
Some Things Never Change,
Scott
