About the Antenna
I recently bought a Yaesu ATAS-120A active tuning antenna. Despite its compact 40m–70cm multiband design, it performs quite well on shortwave and is usable on VHF/UHF, especially with extra ground radials. It is designed for mobile use but works well as a balcony antenna too. Due to its power requirements, size, and weight, I would not recommend it for SOTA though.
This antenna needs proper ground to work. Without it, the tuning motor won't find a match and the antenna won't perform. A car roof or metal railing provides this naturally — a desk indoors does not.
How It Works
Mount the antenna on a surface with good ground (car roof, metal balcony railing), connect it to a supported Yaesu radio (FTX-1, FT-991A, FT-710, FT-891 and others), and select ATAS as your tuner in the radio menu. Hit Tune and watch the antenna extend or retract until it stops at the lowest SWR.
There is also a manual option with the Yaesu handheld mic: hold PTT, then press Down (lower frequency) or Up (higher frequency).
Troubleshooting
What if it won't tune?
- Start with proper ground. Put the antenna on your car roof or a metal railing and test there first. Don't waste time trying it indoors or on a poor ground surface — this is the number one reason the ATAS-120A fails to tune.
- Check radio setup. Make sure ATAS is selected as the tuner in your radio's menu.
- Check your coax. A bad cable or connector can prevent tuning just as easily.
The antenna is mechanically simple and robust — there is no latch or lock. If the motor doesn't move, it's almost certainly a ground or setup issue, not a mechanical one.
Don't try to force it.