DATA S H E E T HIGH POWER TRAVELING WAVE TUBE FOR GROUND TERMINALS LD7246A 14 GHz, 123 W CW, CONDUCTION COOLING, MINIMUM SIZE GENERAL DESCRIPTION NEC LD7246A is PPM-focused traveling wave tube designed for use as final amplifier in the earth-to-satellite communications transmitter. This is capable of delivering an output power of 130 W over the range of 13.75 to 14.5 GHz. It provides a high power gain of 53 dB at 123 W output power. Furthermore, this is of rugged and reliable design offering long-life services. FEATURES ™ Light weight, Compact and Efficient The tube has dual-depressed collectors and is designed to operate at high efficiency across wide power output range. It features state-of the art techniques to optimize size and efficiency. ™ High Power Gain The power gain is typically 53 dB at 123 W level. ™ Simple Cooling System The tube is conduction-cooled, so that the cooling system is greatly simplified. ™ PPM Focusing The tube is PPM (Periodic Permanent Magnet) -focused, eliminating entirely focusing power supplies and interlock circuits. ™ Rugged Construction The tube is designed to be rugged, therefore it is suitable for transportable systems. ™ Long Life and High Stability The tube employs an advanced impregnated cathode with a low operating temperature for long life. ™ Microdischarge Free The tube is carefully designed to be free from microdischarge in the electron gun for long term operation, therefore it is suitable for digital communication service. For safe use of microwave tubes, refer to NEC document “Safety instructions to all personnel handling electron tubes” (ET0048EJ∗V∗UM00) The information in this document is subject to change without notice. Document No. ET0205EJ1V1DS00 Date Published August 1998 M Printed in Japan © 1996 LD7246A GENERAL CHARACTERISTICS ELECTRICAL Frequency ……………………………………………… 13.75 to 14.5 GHz Output Power ………………………………………… 123 W Heater Voltage ………………………………………… 4.5 V Heater Current ………………………………………… 1.0 A Type of Cathode ……………………………………… Indirectly heated, Impregnated Cathode Warm-up Time …………………………… 180 s MECHANICAL Dimensions …………………………………………… See Outline Weight ………………………………………………… 1.3 kg approx. Focusing ……………………………………………… Periodic Permanent Magnet Mounting Position …………………………………… Any Electrical Connections ……………………………… Flying Leads Heater, Heater-Cathode, Helix, Collector-1, Collector-2 RF Connections Input ………………………………………………… SMA-Female Output ……………………………………………… Mates with UBR-120 Flange Cooling ………………………………………………… Conduction ABSOLUTE RATINGS ( Note 1, 2 and 3 ) ELECTRICAL Heater Voltage ……………………………………… Heater Surge Current Min. Max. Unit 4.2 4.8 V …………………………… – 2.5 A Heater Current ……………………………………… – 1.3 A Heater Warm-up Time …………………………… 180 – s Helix Voltage ……………………………………… 6.0 6.4 kV Helix Current ……………………………………… – 5.0 mA Collector-1 Voltage ………………………………… 3.1 3.3 kV Collector-2 Voltage ………………………………… 1.5 1.7 kV Cathode Current …………………………………… – 140 mA RF Drive Power …………………………………… – 1.0 dBm Load VSWR ………………………………………… – 1.5 : 1 Min. Max. MECHANICAL Unit Baseplate Temperature 2 Storage …………………………………………… –30 +110 ˚C Operation ………………………………………… –30 +110 ˚C LD7246A TYPICAL OPERATION (Note 2, 3 and 5) Unit Frequency ……………………………………………… 13.75 to 14.5 GHz Output Power ………………………………………… 130 W Heater Voltage (Note 4) ……………………………… 4.5 V Heater Current ………………………………………… 1 A Helix Voltage …………………………………………… 6.2 kV Helix Current …………………………………………… 3 mA Collector Voltage-1 …………………………………… 3.2 kV Collector Current-1 …………………………………… 80 mA Collector Voltage-2 …………………………………… 1.6 kV Collector Current-2 …………………………………… 42 mA Cathode Current ……………………………………… 125 mA Power Gain at 6 W ………………………… 58 dB at 130 W ……………………… 53 dB Gain Variation at 13 W ……………………… 2 dB/750 MHz Gain Slope at 13 W ……………………… 0.03 dB/MHz 3.5 deg./dB (two equal carriers, 13 W total) …………………… –32 dBc Efficiency ……………………………………………… 38 % AM-PM Conversion at 130 W ……………………… 3rd Order Intermodulation Note 1 : Absolute rating should not be exceeded under continuous or transient conditions. A single absolute rating may be the limitation and simultaneous operation at more than one absolute rating may not be possible. Note 2 : The tube body is at ground potential in operation. Note 3 : All voltages are referred to the cathode potential exept the heater voltage. Note 4 : The optimum operating parameters are shown on a test performance sheet for each tube. Note 5 : These characteristics and operating values may be changed as a result of additional information or product improvement. NEC should be consulted before using this information for equipment design. This data sheet should not be referred to a contractual specification. 3 LD7246A LD7246A OUTLINE (Unit in mm) 14.25 13.21 14.25 13.21 19 38 38 9.6 Output Flange RF Out put Mates With UBR-120 Flange 40 42 7 20 315 50 Max. 275 295 230 93 80 90 40 30 34 RF Input SMA Female HV Lead Wires Length : 300 35 NEC Corporation does not assume any liability for infringement of patents, copyrights or other intellectual property rights of third parties by or arising from use of a device described herein or any other liability arising from use of such device. No license, either express, implied or otherwise, is granted under any patents, copyrights or other intellectual property rights of NEC Corporation or others.