Summary
VHF/AM Aviation Ground Station - Rack Unit (RU) Size: Standard 1U to 3U height, depending on power amplification (usually 1.75 to 5.25 inches). Width & Depth: Standard 19" EIA rack-mount width; depths typically ranging from 12" to 16". Weight: 11 to 30 lbs (5 to 3.6 kg) depending on built-in power supplies and heat sinks. Operating Temperature: -20C to +60C. Cooling: Passive convection (for low power) or forced-air front-to-rear active cooling (for high output). Frequency Range: 118.000 to 136.990 MHz. Channel Spacing: Selectable 25 kHz and 8.33 kHz. RF Output Power: Typically, 5 W to 50 W, software-adjustable and duty-cycle dependent. Impedance: 50 Ω. Transmitter Duty Cycle: 20% (Continuous RX:TX = 4:1). VSWR (Antenna Mismatch): Protected against antenna mismatch, typically rated for less ≤ 6:1 without damage. Input Voltage: Dual-source compatibility is common—100 - 230 V AC (nominal) and/or 24 V DC to 48 V DC for battery backup. Modulation Types: Amplitude Modulation (A3EJN). Modulation Depth & Distortion: Depth ≥ 85%; Distortion ≤ 10%. Receiver Sensitivity: < 1.5 mu V for 12 dB SINAD. Frequency Stability: ±1.0 ppm or better to ensure compliance with regulatory
standards. Adjacent Channel Power: ≥ 50dB at 8.33 kHz; ≥ 60 dB at 25 kHz. AF-Line Input Level: -20 to +10 dBm (adjustable).