The mast preamplifier DBA 1000 is used to improve the reception properties of amateur radio stations in the 6 m and 4 m band. Due to the already built-in diplexer, only one RF socket is required toconnect the (dual-band) antenna and the derivation cable. The automatic transmit / receive switchover (VOX) switches the amplifier off when transmitting and on again when receiving. The maximum switchable power is effectively 100 watts. With higher transmission powers, a sequencer must be used to control the system. The amplifier is equipped with a UV-resistant, weatherproof housing and N sockets. Hot-dip galvanized clamps and assembly material made of V2A are included in the scope of delivery.
The DBA 270 preamplifier is attached directly to the antenna mast near the antenna using the clips supplied. The connection sockets must point downwards, otherwise rainwater can penetrate the device. Low-loss coaxial cables should be used to connect the amplifier, e.g. B. Ecoflex 10 or Ecoflex 15. The antenna input ("ANT" socket) of the amplifier should be connected to the antenna with the shortest possible coaxial cable. The output ("TRX" socket) is connected to the antenna socket of the transceiver using a coaxial cable.
With the direct power supply via the UHF socket (13.8V), the preamplifier is connected using a coaxial cable, e.g. Aircell 7, connected to the power supply. The inner conductor of the cable is connected to the positive (+) pole, the shielding to the negative (-) pole of the power supply unit. The power supply can also be installed directly under the roof. In this case, however, only VOX operation is possible and the preamplifier cannot be switched off when receiving. When using a transceiver with LNA remote power supply, the output of the amplifier ("TRX" socket) is connected to the antenna socket of the transceiver using a coaxial cable. In this case, the amplifier can be activated or deactivated during reception using the LNA button on the front panel of the transceiver. If the transceiver used does not have an LNA power supply, a remote feeder can be used for transmission powers up to a maximum of 100 W. e.g.. DCC 5000 pro, can be connected upstream of the antenna socket for remote powering of the preamplifier. In this case, the power supply can come from the transceiver's power supply unit. The transmit / receive switchover is implemented by the VOX circuit of the preamplifier, but it is possible to deactivate the preamplifier during reception by switching off the power supply from the remote feeder. For transmission powers over 100 W when using a power amplifier with an internal sequencer, the preamplifier is fed remotely via the antenna socket of the power amplifier. When using a power amplifier without an internal sequencer, an external sequencer, e.g. DCW 2004 B to use.