DC9DZ: Project Tsunami – 15Kw HF Power Amplifier using 4CX10000D
Project Tsunami or 3 years of work due to a bet about a crate of Bitburger beer
Burkhard, DF5XV, www.classicbroadcast.de, owns a Monster-PA of R&S called VK20. The live weight of this PA amounts to 1.6 metric tons, it needs a big room on its own with a defined supply and exhaust air and its output reaches frightening 20 Kilowatts, even for RTTY. As a driving transmitter a R&S SK01 is required. Burkhard has an official permission of the BNA for 20 KW on shortwave for broadcast, although not for ham radio. Such enormous values of transmitting power challenge even the creativity of an experienced high frequency engineer. Well, three years ago, the author of this article placed a bet against Burkhard to build a power amplified with more than half the output power of the VK20 in SSB mode, yet would fit the trunk of a compact car as well as a manageable weight. Burkhard's answer: No way! So the race was on!
After three years have passed, the project with working title “Tsunami” is finally completed. Even the additional difficulty of a minimal required input power of only 100 Watts, achieved by every amateur transceiver, in order to attain the full SSB transmit power of approximately 15 Kilowatts was accomplished. A total amplification of about 21 dB is technically very ambitious as it was not the goal to build a power oscillator.
The tube which satisfies the technical requirements of the project “Tsunami” for sure without reaching its limits is the 4CX10000D. According to the Eimac spec sheet for SSB linear