Yaesu ATAS-25
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| Frequency | 7-450 MHz (40/20/15/10/6 m + 2 m/70 cm) |
| Bands | 40m, 20m, 15m, 10m, 6m, 2m, 70cm |
| TX power | 100 W (100 W HF/6 m (SSB/CW), 50 W AM/FM; 50 W 2 m/70 cm) |
| Modes | SSB, CW, AM, FM, digital |
| Connector | coax connector at the base; mounts on a standard 1/4-inch camera-tripod stud |
| Year | 2003 |
| feedpoint | coax connector at the base; 1/4-inch camera-tripod stud |
Estimated (unverified): base connector type and introduction year (~2003, not firmly established); efficiency loss ~4 dB / 1 S-point is a dealer/reviewer figure, condition-dependent on the radial layout
A genuinely packable multiband portable antenna: 40 through 70 cm from one tripod-mounted whip, hand-tuned to a clean SWR without a bag of mono-band resonators. It is light, complete in the box (radials, radial elements, Allen key), handles 100 watts, and pairs naturally with a small Yaesu field radio - and the real-world loss versus a full-size antenna is only about an S-point with the radials laid out.
Manual tuning is the trade-off: you set it by sliding the coil ring and selecting top sections for each band, which is fiddlier and slower than a motorized or auto-tuner antenna. It is a short, loaded compromise that depends on laying out its radial wires properly for HF, it is meant for temporary use (not permanent outdoor mounting), and you supply the tripod and any duplexer yourself.
A tidy, affordable portable multibander for the QRP/field operator: tripod it, lay the radials, hand-tune the band, and you have 40 meters through 70 centimeters from one light whip. The manual tuning asks for a little patience, but the modest efficiency loss and complete-in-the-box kit make it a sensible companion to a small Yaesu radio.
The Yaesu ATAS-25 is the hand-tuned, tripod-mounted, portable member of Yaesu's Active Tuning Antenna System family - the manual counterpart to the motorized, vehicle-mounted ATAS-120A. Where the 120A drives a motor up the coax to retune itself automatically, the ATAS-25 you tune yourself in the field: you slide a shorting ring along the loading coil and choose how many top sections to fit, resonating the whip for the lowest SWR on the band you want. The reward for that small effort is a single light antenna that covers an unusually wide span - 40, 20, 15, 10 and 6 meters plus 2 meters and 70 centimeters, from 7 all the way to 450 MHz - with no bag of expensive mono-band resonator whips to carry.
It is built for going places. The whole thing collapses to about two feet for transport, extends to roughly seven feet to operate, weighs under a kilogram, and screws onto any standard camera tripod. On HF it uses its supplied radial wires - three lengths plus a spare - laid out on the ground as the counterpoise, while 2 meters and 70 centimeters get their own radial elements; everything you need, including an Allen key, comes in the box. At 100 watts on HF and 6 meters it is a natural partner for the small Yaesu field radios it was designed alongside, the FT-817, FT-857 and FT-897, and it can even run HF (or 6 m) and 2 m (or 70 cm) at the same time with a duplexer.
As with every short, loaded antenna it is a compromise, but a reasonable one: dealers and reviewers put the loss versus a full-size antenna at only about 4 dB - roughly one S-point - provided the radials are properly deployed, which is a fair price for the portability. The honest caveats are that the manual tuning is fiddlier and slower than an automatic system, that HF performance depends on taking the time to lay the radials out, and that Yaesu intends it for temporary field operation rather than permanent outdoor mounting. For the operator who wants one tiny, do-everything antenna to throw in a backpack with a small radio, it earns its place.