YAESU ATAS-25 ACTIVE TUNING ANTENNA SYSTEM

Yaesu ATAS 25

The ATAS-25 is a portable, manually tuned antenna ideal for use with HF transceivers. Designed to mount on a standard camera tripod (1/4” stud), the ATAS-25 is tuned by sliding the loading coil shorting ring up or down and selecting the appropriate number of upper sections. Counterpoise leads are supplied. The ATAS-25 is constructed of high quality materials for maximum efficiency and is the ideal traveling companion for your HF transceivers!

Antenna adjustment procedures
1. Referring to the following figure, raise and lower the coil assembly while listening for band noise and find the position where the coil assembly produces the most noise in the receiver. If you do not get peak sensitivity when the coil is fully retracted to the lowest (shortest) position possible, remove one radiating element from the coil assembly and try again. The overall antenna length may be too long.
2. Set the transmitter to CW mode and check the SWR meter reading.
3. Referring again to the following figure, carefully rotate the coil assembly to the right or left while the transceiver is receiving. When the adjustment is complete, move away from the antenna and check the SWR again; repeat (or reverse) the procedure until
to obtain the optimal SWR. Do not touch the coil during transmission.

Technical features

Frequency range: 7/14/21128150/144/430 MHz Amateur bands
Height (approx.): Max. 2.2m during use Min. 0.6m for transportation
Weight (approx.): 930 g
Input impedance: 50Ω
Max. input power: HF/50MHz: 100W (SSB/CW, 50% duty cycle) 50W (AM/FM) 144/430 MHz: 50W (ALL MODE)
ROS granted: less than 2.0:1

Items supplied
Radiant elements
Radiating element (for VHF band)
Radiating element (for UHF band)
Radial cables (6m, 3m and 2m long)
Spare radial cable (10m long)
Hex key