Product Description
DCI Passband Filter – 431.75-437.5 MHz, High-Performance RF Filter for Communications
This used DCI (Microwave) passband filter is a precision RF component designed to pass signals in the 431.75-437.5 MHz frequency range while attenuating out-of-band signals. This band is significant for several applications, including the 70cm amateur radio band (430-440 MHz) and various commercial/industrial uses.
DCI Microwave was a respected manufacturer of high-quality RF and microwave components, including filters, couplers, and other passive devices for communications, defense, and test applications.
Frequency Band Applications
The 431.75-437.5 MHz passband covers key applications:
| Band/Service | Frequency Range | Application |
|---|---|---|
| 70cm Amateur Radio | 430-440 MHz | Weak signal, satellite (AO-7, FO-29), ATV, repeaters |
| ISM Band | 433.05-434.79 MHz | Industrial, Scientific, Medical devices |
| Land Mobile | 450-470 MHz | Commercial two-way radio (nearby) |
| Tetra | 380-430 MHz | European trunked radio (nearby) |
| Radiolocation | 420-450 MHz | Military and government radar |
This filter is ideal for amateur satellite work, where the 435 MHz downlink is common, or for cleaning up signals from ISM devices operating in the 433 MHz band.
Key Specifications
| Specification | Details |
|---|---|
| Manufacturer | DCI Microwave (Microwave Development Company) |
| Type | Passband filter (bandpass) |
| Passband | 431.75 – 437.5 MHz |
| Center Frequency | ~434.6 MHz |
| Bandwidth | ~5.75 MHz |
| Impedance | 50 ohms (typical) |
| Connectors | [Likely SMA, N-Type, or BNC – inspect] |
| Insertion Loss | [Low in passband] |
| Rejection | [High out-of-band] |
| VSWR | [Low in passband] |
| Power Handling | [If known, watts] |
Applications
-
Amateur Radio: 70cm band operation, satellite downlink reception
-
Satellite Communications: Ground station filtering
-
Land Mobile: Commercial two-way radio systems
-
ISM Devices: Filtering for 433 MHz industrial/scientific/medical equipment
-
Test & Measurement: Harmonic and spurious rejection
-
Receiver Front-End: Preventing out-of-band interference
-
Transmitter Output: Cleaning up transmitted spectrum
Condition
SOLD AS IS
USED – SHOWS NORMAL WEAR (scuffs, minor marks)
RF PERFORMANCE NOT TESTED
NO MOUNTING HARDWARE OR DOCUMENTATION INCLUDED
PICTURE MAY NOT MATCH PRODUCT



