Antennas-Amplifiers 6311 2‑meter 200W Narrow Band Pass Filters are engineered to deliver reliable, high-performance signal conditioning across the full U.S. 2‑meter amateur band (144–148 MHz). Designed to handle power levels up to 200 watts, these filters effectively refine transmitter output while also serving as protective front-end filters for broadband preamplifiers, shielding sensitive equipment from unwanted out-of-band signals. Built with precision high‑Q coils and premium capacitors, they achieve exceptionally low insertion loss while maintaining outstanding selectivity. These filters also help mitigate TVI issues and reduce interference from nearby strong transmitters on HF, 6m, or 70cm bands, ensuring smoother operation and improved coexistence with neighboring systems.

Insertion Loss / Attenuation (Measured)

HF Band:

• 1.8 MHz — 109 dB

• 3.8 MHz — 109 dB

• 7.1 MHz — 100 dB

• 14.1 MHz — 100 dB

• 21.2 MHz — 93 dB

• 28.4 MHz — 82 dB

Low VHF (6 m / adjacent):

• 50 MHz — 68 dB

• 54 MHz — 65 dB

• 70.2 MHz — 55 dB

VHF Broadcast Band:

• 88 MHz — 44 dB

• 108 MHz — 30 dB

Passband (2 m Band):

• 144–148 MHz —0.2 dB insertion loss

• Return Loss — −35 dB

Above Band / Harmonics:

• 222.2 MHz — 41 dB

• 288 MHz — 54 dB

• 432.1 MHz — 56 dB

• 1296 MHz — 35 dB

Maximum Power Input vs SWR

• 1.0 : 1 — 200 W

• 1.5 : 1 — 140 W

• 2.0 : 1 — 110 W

• 3.0 : 1 — 85 W (50% duty cycle / intermittent)

Specifications:

Frequency range: 144–148 MHz (full U.S. 2‑meter band coverage)

Power handling: Up to 200W (depending on SWR conditions)

Insertion loss (in-band): ~0.2 dB with return loss around −35 dB

Impedance: 50 ohms

Out-of-band attenuation: Strong suppression across HF, 6 m, VHF, and UHF ranges (e.g., 50 MHz ~68 dB, 432 MHz ~56 dB)

Maximum input power (by SWR): 200W @ 1:1, 140W @ 1:1.5, 110W @ 1:2, 85W @ 1:3

Design: High‑Q coils and capacitors for low loss and high selectivity