User manual YAESU ATAS-25

[. . . ] The ATAS-25 allows dual-frequency operation (on HF or 50 MHz and either 144 or 430 MHz), if two transceivers are combined via a suitable diplexer (not supplied). The ATAS-25 is designed to mount directly onto a standard camera tripod (not supplied); see Figure 1. OPERATION For the 144/430 MHz bands, you may operate instantly without making any adjustments. For HF/50 MHz operation, perform the following procedures for antenna adjustment: 1. [. . . ] It helps the accuracy of the SWR measurements if all people are standing at least 10 feet (3 m) away from the radiating element, anyway, to minimize inaccuracies due to mutual coupling to the human figure(s) in the vicinity. If erratic transceiver operation is observed, there may be common-mode current flowing on the shield of the coaxial cable. Make an RF choke by coiling about eight turns of cable into a coil of diameter approximately 6" (roughly 150 mm) near the ATAS-25, taping the coils to hold them in place. If this does not eliminate the problem, reverse the coax ends, placing the coil near the transceiver. If additional cable is available, place a coil at both ends of the coaxial cable in difficult cases. Set up the tripod as low and level as possible, for maximum stability of the tripod/antenna assembly. SWR tends to be best with the base of the ATAS-25 near the ground, as well (Figure 1). Should the ATAS-25 get wet due to rain, wipe off the antenna's components using a dry cloth, then completely dry the ATAS-25 overnight with the coil assembly fully extended. For SSB/CW DX operation on the 144/430 MHz bands, remember that the convention for polarization in most areas is horizontal, not vertical, so we recommend the ATAS25 mostly for local FM work on those bands. Make every effort to install the ATAS-25 away from areas where people might trip over the tripod legs, coaxial cable, or counterpoise wires. We strongly recommend that the tripod legs be staked firmly to the ground, or the tripod and antenna be otherwise secured with guy ropes and stakes, to prevent the antenna from accidentally tipping over, so as to avoid injury to bystanders and/or damage to antenna components. VERTEX STANDARD CO. , LTD. 4-8-8 Nakameguro, Meguro-Ku, Tokyo 153-8644, Japan INSTALLATION 1. Referring to Figure 2 and the following chart, connect the radiating elements according to the operating band, then screw the radiating element securely to the top of the coil assembly of the ATAS-25. OPERATING BAND 7 MHz 14 MHz 21 MHz 28 MHz 50 MHz 144 MHz 430 MHz RADIATING ELEMENT(S) Three Elements Three or Two Elements Two Elements Two or One Element(s), or No Connection Do Not Connect Not Used Not Used have to be moved manually to the appropriate antenna jack when you wish to operate on VHF or UHF. While operation is not guaranteed on the 10/18/24 MHz bands, please feel free to experiment on these bands, as low SWR and good efficiency will be obtained in many instances. NOTE: When the ATAS-25 is fitted with two radiating elements, use the top radiating element (the one with the rubber cap) and the bottom radiating element (the one with the threaded adapter at the bottom). When the ATAS-25 is fitted with only one radiating element, move the threaded adapter to the bottom of the element with the rubber cap, then screw that element onto the top of the coil assembly (Figure 3). Secure the V/UHF radial elements to the bottom of the ATAS25 main body, using the supplied Allen wrench (Figure 4). Connect the supplied radial wires to the bottom of the ATAS25 main body, then extend them outward from the antenna base (Figure 5). Connect the coaxial cable from the transceiver's HF antenna jack (see Figure 6). Typically, you can use the builtin SWR meter in the transceiver, but alternatively you may adjust the SWR using an "Antenna Analyzer" prior to connecting the coaxial cable to your transceiver. [. . . ] 1 Spare Radial Wire (32. 8 ft (10 m) Length) . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Allen Wrench . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Operating Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ]