NEC LD7237 Datasheet

DATA SHEET

HIGH POWER TRAVELING WAVE TUBE

FOR DBS GROUND TERMINALS

LD7237

DBS Band, 400 W CW, PPM FOCUSING, HIGH POWER GAIN

GENERAL DESCRIPTION

NEC LD7237 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 400 W over the range of 17.3 to 18.1 GHz and provides a high

power gain of 53 dB at 400 W output power.

Furthermore, this is of rugged and reliable design offering long-life service. LD7237 is fully compatible with TH3694B.

FEATURES

™ High Power Gain

The power gain is typically 53dB at 400 W level.

™ Simple Cooling System

The tube is forced-air-cooled, so that the cooling systems are greatly simplified.

™ PPM Focusing

The tube is PPM (Periodic Permanent Magnet)-focused, eliminating entirely the focusing power supplies and

interlock circuits.

™ Rugged Construction

The tube is designed to be rugged, therefore it is suitable for the 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)

Document No. ET0159EJ2V1DS00 Date Published August 1998 M Printed in Japan

The information in this document is subject to change without notice.

1996

LD7237

GENERAL CHARACTERISTICS

ELECTRICAL

Frequency .................................................................................. 17.3 to 18.1 GHz

Output Power ............................................................................ 400 W

Heater Voltage........................................................................... 6.3 V

Heater Current........................................................................... 1.4 A

Type of Cathode........................................................................ Indirectly heated, Impregnated

Cathode Warm-up Time ........................................................... 300 s

MECHANICAL

Dimensions................................................................................ See Outline Drawing

Weight........................................................................................ 6.0 kg approx.

Focusing .................................................................................... Periodic Permanent Magnet

Mounting Position .................................................................... Any

Electrical Connections .............................................................. AMP 861647-8 multi-pin connector

Heater, Heater-Cathode Helix, Anode, Collector and Thermal Protection

RF Connections

Input ................................................................................... Mates with SMA-Female

Output ................................................................................ Mates with UBR-140 Flange

Cooling....................................................................................... Forced Air

LD7237

ABSOLUTE RATINGS

ELECTRICAL

Heater Voltage.................................................................. 6.0 6.6 V

Heater Surge Current ...................................................... – 4.5 A

Heater Current.................................................................. – 3.0 A

Heater Warm-up Time ..................................................... 300 – s

Helix Voltage .................................................................... 9.5 10.75 kV

Helix Current .................................................................... – 15 mA

Anode Voltage.................................................................. 8.55 10.25 kV

Anode Current.................................................................. – 0.5 mA

Collector Voltage.............................................................. 4.0 5.5 kV

Cathode Current............................................................... – 350 mA

RF Drive Power ................................................................ – 25 mW

Load VSWR ...................................................................... – 1.5

MECHANICAL

Temperature at output Flange ........................................ – 100 ˚C

Air Flow ............................................................................ 195 – kg/hr

Ambient Temperature

Storage ..................................................................... –40 +80 ˚C

Operation.................................................................. –10 +50 ˚C

(Note 1, 2 and 3)

Min. Max. Unit

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