Keysight (Agilent) 87405A Preamplifier, 10 MHz to 3 GHz

The Keysight (Agilent) 87405A is a wideband preamplifier designed to boost weak RF signals across the 10 MHz to 3 GHz frequency range. It delivers 22–27 dB of gain with ±1.25 dB flatness (50–3000 MHz), enabling improved sensitivity in spectrum analysis, noise figure measurements, and signal detection applications. The unit operates at +15 Vdc, 80 mA and dissipates 1.2 W, making it suitable for portable and bench-top measurement systems.

Technical Specifications

• Frequency Range: 10 MHz to 3 GHz


• Gain: 22–27 dB (min/max); 25 dB minimum (2–3 GHz); Flatness ±1.25 dB (50–3000 MHz), ±2.0 dB (10–3000 MHz)


• Noise Figure: 6.5 dB typical (0.01–2 GHz); 7.5 dB typical (2–3 GHz)


• Output Power: 4 dBm (2–3 GHz); 1 dBC compressed output at 4 dBm


• Third Order Intercept (TOI): 15 dBm typical


• Harmonics: 20 dBc typical at +4 dBm output


• Input VSWR: 1.5:1 (10–1000 MHz); 1.7:1 (1000–2000 MHz); 2.0:1 (2000–2900 MHz); 2.2:1 (2900–3000 MHz)


• Output VSWR: 2.0:1


• Impedance: 50 Ω nominal


• Reverse Isolation: 60 dB typical


• Survival Input Power: +13 dBm typical


• Operating Temperature: 0°C to +55°C


• Storage Temperature: −40°C to +70°C

Key Features

• Dual Type N connectors (female input, male output)


• 50 Ω matched system impedance


• Power supply requirement: +15 Vdc at 80 mA via probe power connector


• Low power dissipation: 1.2 W nominal


• Mil-Std-883C environmental compliance (humidity, vibration, shock, altitude)


• Net weight: 270 g

Typical Applications Front-end amplification for spectrum analyzers, noise figure measurements, weak signal detection, and RF receiver sensitivity enhancement across VHF through low-microwave frequencies.

Compatibility & Integration Direct interface with Keysight 8590E series portable spectrum analyzers and 8594E Noise Figure Measurement Solution. Requires optional 11899A Probe Power Supply (100 V, 120 V, 220 V, or 240 V).