Kenwood TM-251A Instruction Manual

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Note:» For your transceiver to fully exhibit its performance capabilities,the following optional power supply is recommended:PS-33 (20.5 A, 25% duty cycle).» Before connecting the DC power supply to the transceiver, besure to switch the transceiver and the DC power supply off.> Do not plug the DC power supply into an AC outlet until you makeall connections.m Replacing FusesIf the fuse blows, determine the cause then correctthe problem. After the problem is resolved, only thenreplace the fuse. If newly installed fuses continue toblow, disconnect the power plug and contact yourdealer or nearest Service Center for assistance.Fuse Location Fuse Current RatingTM-251NVE 15ATM-451NVE 10ASupplied Accessory 20ADC Power CableCAUTION: Only use fuses of the specified type and rating.ANTENNA CONNECTIONThe type of the antenna system, consisting of theantenna, ground, and feed line, will greatly affect thesuccessful performance of the transceiver. Use aproperly adjusted 50 ohm antenna of good qualitydesigned for operation at your operating frequency to letyour transceiver perform at its best.Install low-loss 50 ohm coaxial cable and a first qualityconnector for the connection to the transceiver. Forlonger feed line runs, especially for operation at UHFfrequencies, you might consider investing in "hardline"transmission line. Hardline is available in largerdiameters and has much lower loss than coaxial cable.The lower loss can make a significant difference forthose interested in weak signal operation. In all cases,match the impedance of the feed line and antenna sothat the SWR is minimum. Generally, an SWRmeasurement of 1.5:1 or less is considered satisfactory.All connections must be clean and tight. Coupling theantenna to the transceiver via feed line having animpedance other than 50 ohms reduces the efficiency ofthe antenna system. It also can cause interference tonearby broadcast television receivers, radio receivers,and other electronic equipment.CAUTION:> All fixed stations should be equipped with a lightning arrester toreduce the risk of fire, electric shock, and transceiver damage.> Transmitting without first connecting an antenna or othermatched load may damage the transceiver. Always connect theantenna to the transceiver before transmitting.