EAST COAST HOLLAND D.D.S. PWM SHORTWAVE T.X.

GENERAL DESCRIPTION

East Coast Holland D.D.S. PWM SHORTWAVE T.X.

PRODUCT OVERVIEW

This high-performance shortwave transmitter delivers reliable signal control and robust power management.

It features a Direct Digital Synthesis (DDS) control system and dual power amplifiers connected in series, operating at a maximum of 70 Volts.

Thanks to the integrated Pulse Width Modulator (PWM), users can precisely control and adjust the power output.

The transmitter also includes advanced protection systems to monitor temperature and signal reflection, ensuring safe and continuous operation.

photo East Coast Holland D.D.S. PWM SHORTWAVE T.X.

SAFETY AND PROTECTION FEATURES

SWR Protection: Antenna reflection alarm and automatic power amplifier shutdown managed by the DDS
Temperature Monitoring: 3 dedicated sensors tracking the heatsink, PWM FET, and exhaust air temperature
Thermal Alarm: Adjustable threshold between 35°C and 80°C
Thermal Shutdown: Automatically turns off the power amplifiers if temperature limits are exceeded

TECHNICAL SPECIFICATIONS
Frequency Range	3900 kHz to 7500 kHz (continuously tunable)
Frequency Step Sizes	1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, and 1 MHz
Control System	Direct Digital Synthesis (DDS)
Power Amplifiers	Dual stages connected in series (70V maximum)
Power Control	Pulse Width Modulation (PWM)
Carrier Power Range	15W to 350W (fully adjustable)
Harmonic Suppression	5-stage Low-Pass Filter (LPF) providing over 35dB suppression on the first harmonic
Automatic Volume Regulation (AVR)	Built-in limiter via DDS, adjustable up to a maximum of 125% modulation
Power Supply Configuration
Control Circuit Power	1x 12V DC @ 6A
Amplifier Power Stage	1x 48V DC @ 20A and 1x 24V DC @ 13A connected in series to achieve the 70V rail voltage
Physical Specifications
Width	48 cm (18.9")
Depth	40 cm (15.7")
Height	17 cm (6.7")
Weight	Approx. 18 kg (39.7 lbs)

TUBE COMPLEMENT
RF stages		AF stages and modulator
Number	Type	Number	Type
-	-	-	-

THIS TYPE OF TRANSMITTER IS INSTALLED IN THE FOLLOWING COUNTRIES
	ITU	Country	ITU	Country
	DNK	DENMARK	HOL	NETHERLANDS