Pomona Electronics 3.75 MHz Band Pass Filter Mountable BNC In/Out 20dB

Pomona Electronics 3.75 MHz Band Pass Filter Mountable BNC In/Out 20dB

This Pomona Electronics band pass filter is centered at 3.75 MHz and is housed in a compact, mountable aluminum enclosure. It provides a narrow passband for isolating signals near 3.75 MHz, with BNC connectors for signal input and output and a front-panel rotary control that adds up to 15 dB of additional signal attenuation. A calibration sticker from Scope-Teka is affixed to the front panel, indicating it has been calibrated to specification.

Specifications & What's Included

• Center Frequency: 3.75 MHz (peak response at 3.79 MHz)
• Insertion Loss: 20.2 dB
• Q Factor: 26.6
• –3 dB Bandwidth Limits: 3.716 MHz to 3.858 MHz
• –20 dB Bandwidth Limits: 3.53 MHz to 4.09 MHz
• Additional attenuation: up to 15 dB via front-panel volume/attenuator control
• Input connector: BNC (labeled IN)
• Output connector: BNC (labeled OUT)
• Front-panel ON toggle switch
• Form factor: compact aluminum enclosure with mounting flanges
• Calibrated by Scope-Teka (sticker present on front panel)

Applications

Band pass filters in the low-MHz range are used in RF signal chains, test benches, and receiver front ends to pass a narrow band of frequencies while attenuating out-of-band signals. A 3.75 MHz center frequency falls within the HF spectrum and is relevant to amateur radio (particularly 80-meter band work), legacy telemetry systems, and general-purpose RF laboratory testing. The combination of a fixed LC or crystal filter element with a variable attenuator on the output makes this style of filter particularly practical for bench use, where the engineer needs both frequency selectivity and convenient level control in a single small unit. Pomona Electronics is a long-established manufacturer of electronic test accessories and passive RF components, and their mountable filter housings like this one were widely used in both production test environments and research labs from the 1970s onward.