Bias Tee DC BOX by Jan OK2ZAW

A bias tee is used to insert DC power into an HF signal to power remote antenna amplifiers or other devices. It is usually positioned at the receiving end of the coaxial cable to pass DC power from an external source to the coaxial cable running to powered device. A bias tee consists of a feed inductor to deliver DC to a connector on the device side and a blocking capacitor to keep DC from passing through to the receiver. Bias tees are used in a variety of applications, but are generally used to provide an RF signal and (DC) power to a remote device where running two separate cables would not be advantageous.

Main functions:

• Info:
  • Broadband: 0.1 MHz to 60 MHz
  • Variable ATTENUATOR pic
  • Front-end protection with diodes pic
  • This version includes HPF (100kHz) to avoind AC noise to RX
  • Power supply common-mode filter
  • DC short protection
  • High voltage and current protections
  • LED diode indication of DC power on the coax
• You can set ATT when you have too high gain of preamp.
• Connectors can be SO-239, F or adapters PL-239 to F for universal use
• BOX size 100x100 mm
• Available as
  • ASSEMBLED and tested
  • KIT : all parts + PCB (OLDER THT version without HPF)
  • PCB (OLDER THT version without HPF) only

Parameters:

• Supply voltage DC up to 24 V
• Supply current up to 500 mA
• Insert loss lower than 1dB - for minimal ATT
• High Pass Filter > 100kHz ( AC noise limiter)

Use:

• Providing an RF signal and (DC) power to a remote device over one coax
• You can use bias tee on both sides as DC IN and OUT from RF coax

The measured values

ATT OFF: SWR, insert loss	ATT set to 10dB: SWR, insert loss

Example with Bias-tee DC BOX and Bi-Dir beverage antenna:

Example with Bias-tee DC BOX and Bi-Dir beverage antenna and preamp in hamshack:

Example with Bias-tee DC BOX and RX preamp BOX:

Download

Bias Tee BOX
Schematic and board V 0.1:	sch	brd
Schematic and board V 0.2:	sch	brd
Schematic and board V 1.0 (2022):	sch	brd
Attribution-NonCommercial 2.0 Generic