Key Advantage:

At microwave frequencies (>1 GHz), cable losses can exceed 10-20 dB. By amplifying signals at the antenna before cable transmission, active horns recover these losses and can detect emissions 30-40 dB lower than passive antenna setups with equivalent receivers.

📡 AHA-118: 1-18 GHz Active Horn (Usable from 700 MHz)

Applications & Use Cases:

• 5G Device Testing (Sub-6 GHz): Covers all 5G FR1 bands (600 MHz - 6 GHz) for testing smartphones, tablets, IoT devices, and wireless infrastructure. The 40 dB preamp enables detection of weak spurious emissions from power amplifiers and local oscillators.
• WiFi 2.4/5/6 GHz Testing: High sensitivity ideal for measuring low-level emissions from WiFi 6E devices (2.4/5/6 GHz) and WiFi 7 devices per FCC Part 15, ETSI EN 301 893
• ISM Band Testing: Covers 2.4 GHz (Bluetooth, ZigBee), 5.8 GHz (UNII bands), and other ISM frequencies for wireless sensor networks, smart home devices, industrial controls
• Automotive Radar Emissions: 24 GHz short-range radar (parking sensors, blind spot detection) emissions testing per CISPR, automotive OEM specifications
• Satellite Communications: C-band (4-8 GHz), X-band (8-12 GHz), Ku-band (12-18 GHz) emissions from satellite terminals, transponders, earth stations
• Radar Systems: Air traffic control, weather radar, marine radar, military radar emissions testing from 1-18 GHz
• Low-Level Spurious Measurements: The 40 dB preamp brings receiver noise floor down to -140 dBm or better, enabling detection of spurious emissions 60-80 dB below carrier in wireless transmitters
• Chamber Validation: High-sensitivity measurements for site attenuation, site VSWR, quiet zone verification in anechoic chambers >1 GHz

Test Environment Suitability:

• Semi-Anechoic Chamber: Excellent - high sensitivity maximizes dynamic range for low-level emissions in controlled environment
• Fully Anechoic Chamber: Excellent - preamp compensates for longer cable runs from chamber to control room
• Shielded Room: Very Good - improved sensitivity in isolated environment, but monitor for preamp saturation from nearby transmitters
• OATS: Good - weather-resistant construction suitable for outdoor use, but external RF may saturate preamp (use attenuators if needed)

Setup Tips: Power the preamp using a bias-T inserted between antenna and receiver. For high-amplitude signals (>-20 dBm), insert external attenuators between antenna and preamp to prevent saturation. When used for immunity testing, ensure preamp bypass is activated and verify 300W power handling is not exceeded.

📡 AHA-840: 18-40 GHz Active mmWave Horn

Applications & Use Cases:

• 5G mmWave Testing (FR2): Covers all 5G FR2 bands (24.25-29.5 GHz n257/258/260/261, 37-40 GHz n260) for testing 5G base stations, small cells, mobile hotspots, CPE equipment, smartphones with mmWave capability
• Automotive Radar (77-81 GHz): Although antenna operates to 40 GHz, it can detect harmonic emissions and intermodulation products from automotive long-range radar (76-81 GHz) that fall into the 18-40 GHz range. For fundamental 77 GHz testing, use spectrum analyzer with mmWave mixer.
• 24 GHz Automotive Radar: Direct fundamental measurement of short-range radar emissions (parking sensors, blind-spot detection) at 24-24.25 GHz per CISPR 25, automotive OEM standards
• Satellite Ku/Ka-Band: Ku-band (12-18 GHz, requires AHA-118) and Ka-band (26.5-40 GHz) emissions from satellite terminals, VSAT equipment, satellite phones, ground stations
• Point-to-Point Microwave Links: E-band (71-76/81-86 GHz) harmonics and spurious emissions that fall into 18-40 GHz range from wireless backhaul equipment
• Radar Cross-Section (RCS) Measurements: Used in bistatic RCS test setups at 18-40 GHz for defense, aerospace, automotive applications
• mmWave Research & Development: High sensitivity enables detection of low-level emissions from mmWave prototypes, beam-forming arrays, phased array antennas, and experimental wireless systems

Test Environment Suitability:

• Anechoic Chamber: Excellent - controlled environment essential for mmWave testing; preamp critical due to high cable losses (>20 dB at 40 GHz)
• Shielded Room: Very Good - provides isolation from ambient mmWave signals (5G base stations, radar), preamp maximizes sensitivity
• OATS: Fair - mmWave testing typically done indoors due to atmospheric attenuation, rain fade, and difficulty maintaining alignment outdoors

Setup Tips: Use high-quality 2.92mm precision cables rated for 40 GHz. Keep cable lengths <3 feet where possible. For power >10W, remove coaxial adapter and connect amplifier directly to WR-28 waveguide flange (200W capability). Verify preamp power supply provides clean 12-24 VDC via bias-T.

When to Choose Active Horns:

Choose active horns when measuring low-level emissions (<-60 dBm), testing in anechoic chambers with long cable runs (>10 feet), working above 10 GHz where cable losses are severe, or when maximum sensitivity is critical. Choose passive horns when measuring high-power signals, operating in high-RF environments (to avoid saturation), when simplicity is preferred, or when budget is constrained.

Receive Mode Setup (Emissions Testing)

1. Power Connection: Connect 12-24 VDC power supply to bias-T input. Verify preamp LED indicator (if present) illuminates.
2. Cable Connection: Connect bias-T RF output to spectrum analyzer or EMI receiver input using quality coaxial cable rated for operating frequency (Type-N for AHA-118, 2.92mm for AHA-840).
3. Antenna Connection: Connect bias-T RF/DC output to antenna input port. The bias-T supplies DC power while passing RF signal bidirectionally.
4. Preamp Verification: Inject a known low-level signal (e.g., -80 dBm from signal generator) and verify 40 dB gain. Measured level should be approximately -40 dBm.
5. Saturation Check: If measuring strong signals (>-30 dBm), insert external attenuators (3-10 dB) between antenna and preamp to prevent compression/saturation.
6. Calibration: Apply antenna factor correction (provided with antenna) PLUS preamp gain correction in measurement software or receiver.

Transmit Mode Setup (Immunity Testing)

1. Bypass Preamp: If antenna has physical bypass switch, activate it. If controlled electronically, apply bypass voltage per manufacturer instructions (typically 24V).
2. Remove Bias-T: Disconnect bias-T from signal path. Connect RF amplifier output directly to antenna input.
3. Power Verification: Verify transmit power does not exceed antenna rating: AHA-118 = 300W, AHA-840 = 10W coax / 200W waveguide.
4. Waveguide Option (AHA-840): For >10W, remove coaxial adapter and connect amplifier directly to WR-28 waveguide flange (200W capable).
5. Forward/Reflected Power: Insert directional coupler or power meter between amplifier and antenna to monitor forward/reflected power and ensure VSWR <2:1.
6. Field Strength Calibration: Measure field strength at test distance using calibrated field probe. Adjust amplifier output to achieve required immunity level (e.g., 200 V/m).

Common Setup Issues & Solutions

• Issue: No signal received / preamp not working
  Solution: Verify DC voltage at antenna port (should be 12-24V). Check bias-T connections and power supply.
• Issue: Signal levels too high / receiver overload
  Solution: Preamp may be saturating. Insert 6-10 dB attenuator between antenna and preamp input.
• Issue: Unstable measurements / intermittent signal
  Solution: Check cable connections, especially at 2.92mm connectors (AHA-840). Ensure torque wrench used for precision connectors.
• Issue: Low field strength in immunity mode
  Solution: Verify preamp bypass is activated. Check for high VSWR (>2:1) indicating impedance mismatch.