Software Defined Radio - 100 Watt Linear Amplifier KDG-PA100


KDG-PA100
KDG-PA100



Overview

The linear power amplifier KDG-PA100 is the suitable amplifier for the SDR PCB KDG-SR100. The amplifier is powered by the switching power supply KDG-SNT1.

The PCB linear amplifier and the switching power supply are mounted in the housing KDG-01 together with the PCB KDG-SR100. The power supply KDG-SNT1 then also feeds the SDR PCB. The device together with the computer is a complete transceiver. The linear amplifier is controlled by the computer through the SDR PCB. For this the linear amplifier is connected to the KDG-SR100 by a flat cable. The drive power of 1 Watt is fed to the power amplifier by a BNC cable on the back.

The linear amplifier consists of two stages, the driver stage with two fieldeffect transistors IRF510 and the final stage with two RF-bipolar transistors SD1446. The circuits are designed strictly symmetric to suppress the first harmonic frequency. The impedance matching between the driver and the final stage is done with a transformer as is the matching between the final stage and the lowpass filter. The driver and the final stage are phase compensated to archieve a constant gain over the complete frequency range. The power transistors are mounted on a big aluminum heat sink (100 x 66 x 40 mm). This heat sink is cooled by a radial fan of about 60 mm diameter. The fan normally runs with reduced speed so that it is hardly audible. At the heat sink temperature of 60° C the fan is switched to full power by a thermo switch. The fan sucks the air out of the housing and thereby also cools the power supply and the PCB KDG-SR100. The housing has several holes in the bottom for the entry of the air. The warm air is blown out through slots in the back plate.



PCB KDG-PA100
PCB KDG-PA100





Technical Data

Frequency Range

1,8 MHz – 30 MHz

Power Output

100 W PEP

Driving Power

1 W PEP

Power Supply

13,6 V dc / 18 A

Low Pass Filter

6 Low Pass Filter, switched
by relays (double contacts):
160 m, 80 m, 60/40 m,
30/20 m, 17/15 m, 12/10 m

T/R-Switching

2 relays,
controlled by the computer

SWR measurement

The measurement is done by a
usual circuit. The values are
digitized and sent to the
computer

Cooling

Aluminum heat sink with radial
fan and thermo switch (60 Grad C)


Prices und Availability


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