DBA 1000 Duoband mast amplifier

The DBA 1000 from SSB-Electronic is a low-noise and large-signal-proof mast preamplifier. It is used to improve the reception characteristics of amateur radio stations in the 6m and 4m bands. It is particularly suitable for dual band antennas 4m + 6m with only one feed line. In order to prevent mutual interference with signals from the two frequency ranges, the DBA 1000 is equipped with separate amplifier stages, which are connected to the input and output of the device with diplexer circuits. Due to the already built-in diplexer, only one RF bus is required to connect the (dual-band) antenna and the diversion cable. The preamplifier is equipped with a transmit and receive switch.

The automatic transmit/receive switchover (VOX) switches the amplifier off when transmitting and on again when receiving. The maximum switchable power is 100 watts. At higher powers, the amplifier is controlled and supplied with power using a sequencer. When using a sequence control, the maximum transferable transmission power is 750 watts PEP and 750 watts with CW / FM / WSJT. This amplifier can be supplied with power via the coaxial cable via its remote output. Alternatively, the local power supply can be provided via the UHF connection with a separate line. When using the VOX circuit, this amplifier must have a permanent power supply during operation. It can be supplied locally or remotely. The input and output of this amplifier are protected with amplitude limiters to ensure a high degree of operational reliability.

The input and output circuit of the SSB DBA-1000 amplifier is dimensioned in such a way that both connections have an exact impedance of 50 ohms with very low imaginary components. This ensures that the antenna system is loaded with real 50 ohms and that the parameters of the system are not changed. With the currently most widely used highly optimized narrowband antennas it is very important that they are terminated with real 50 ohms. A mismatch at the input of the used preamplifier can lead to a change in the parameters of such antennas, which results in a loss of gain and an influence on the directional characteristic.

Mounting tips for the DBA-1000

The DBA 1000 preamplifier is supplied with the clamps supplied to be attached directly to the antenna mast near the antenna. The connection sockets must point downwards , otherwise

rainwater can enter the device. To connect the amplifiers, coaxial cables with low loss such as Ecoflex 10 or Ecoflex 15 should be used. The antenna input ("ANT" connection) of the amplifier should be as short as possible for connection to the antenna. The output ("TRX" connection) is connected to the antenna connection of the transceiver.

This amplifier is equipped with a UV-resistant, weatherproof housing and N-socket. Hot-dip galvanized clamps and stainless steel mounting hardware are included in the delivery.