Short Wave Power Amplifier Controller
with big 7" TFT Touch Display


The board DSP-7 can be used as a controller for ham radio power amplifiers (low bands, short wave, VHF/UHF/SHF) and also as a display for power/SWR meters (simultaneous single, dual or triple swr bridges).

This document focuses on the DSP-7 used as power amplifier controller.  It supports most home brew amplifiers and turns it into a professional product.

Available January 2018: www.helitron.de/shop 

these are just three samples out of the 14 screen menus:

Overview Photo realistic History

User Interface: presentation of Power/SWR measurement

Big 7" TFT color touch screen with SD card slot
many convenient screens present measured values and amplifier status
colored bar graphs and numbers
photo realistic power/swr meter simulation
history diagram, selectable recording times
simultaneous power and SWR measured at the input, between amp and LPF and at the output
works with any AD8307 based power/swr bridges by software calibration

User Interface: analog measurements

temperature-1: temperature of the power transistor
temperature-2: temperature of the heat sink
supply voltage (four selectable ranges from 50V to 4kV)
supply current (four selectable ranges from 10A to 200A)
frequency measurement
DC input power
amplifier efficiency

User Interface: amplifier control

ON switch: by touch button or external button
STANDBY: by touch button or external button
ACTIVE: by touch button or external button
Emergency OFF: by touch button or external button

Switching functions:

PTT controller
BIAS on/off (disables the amp's bias voltage in case of errors)
fan or water pump control
DC power supply control
security circuit control
ALC, monitors current consumption to limit drive power, thus is independent from SWR

Band and antenna selection:

band selection via touch button or external rotary switch
automatic selection of up to 3 antennas, comfortable assignment of bands to antennas
automatic band and antenna selection for ICOM transceivers

Security functions:

Monitoring of the supply voltage, total shutdown in case of error
Monitoring of the supply current, total shutdown in case of error
Temperature measurement: automatic fan on/off and disabling TX if exceeding an adjustable limit
controlling the transceiver via ALC to reduce drive power
monitoring the drive power and switching into standby if limit is exceeded
monitoring of the SWR between amplifier and low pass filter, shutdown in case of wrong filter selection
monitoring of antenna SWR. If worse than 2:1 switching into RX mode, if worse than 3:1 emergency shutoff


Integrated WiFi interface
AP (access point) mode
client mode
integrated web server
presentation of measured values and amplifier status
can be viewed by a web browser on PCs and smartphones


serial CI/V interface for future extensions
RS232 interface for firmware updates
users can update many pictures by own graphics with an SD card
powerful ARM Cortex 3/4 micocontroller with 1MB flash
DC supply: 10-15 volts, 250mA
controller and display is one compact unit, easy mounting to front panels
RF tested 4-layer PCB, inputs with EMI ferrites and capacitors
individual full size ground plane
individual power supply planes


Block diagram of a complete amplifier using this controller: