Yaesu ATAS 25
The ATAS-25 is a portable, manually tuned antenna, ideal for use with HF transceivers. Designed for mounting on a standard camera tripod (1/4” stud), the ATAS-25 is tuned by sliding the shorting ring of the loading coil up or down and selecting the appropriate number of upper sections. Counterpoise wires are supplied. The ATAS-25 is made from high-quality materials for maximum efficiency and is the ideal travel companion for your HF transceivers!
Antenna tuning procedure
1. Referring to the figure below, raise and lower the coil assembly while listening to the band noise and look for the position where the coil assembly produces the most noise in the receiver. If a peak in sensitivity is not obtained when the coil is fully retracted to the lowest (shortest) possible position, remove a radiating element from the coil assembly and try again. The overall length of the antenna may be excessive.
2. Set the transmitter to CW mode and check the SWR meter reading.
3. Referring again to the figure below, carefully rotate the coil assembly right or left while the transceiver is receiving. After adjustment, move away from the antenna and recheck the SWR; repeat (or reverse) the procedure until
the optimal SWR is obtained. Do not touch the coil while transmitting.
Technical specifications
Frequency range: 7/14/21128150/144/430 MHz Amateur bands
Height (approx.): Max. 2.2 m during use Min. 0.6 m for transport
Weight (approx.) : 930 g
Input impedance: 50Ω
Max. input power: HF/50MHz: 100 W (SSB/CW, 50% Duty Cycle) 50W (AM/FM) 144/430 MHz: 50W (ALL MODE)
Tuned SWR: less than 2.0 : 1
Supplied items
Radiating elements
Radiating element (for VHF band)
Radiating element (for UHF band)
Radial wires (6 m, 3 m, and 2 m long)
Spare radial wire (10m long)
Hex key
