DC Voltage Common Mode Noise Filter - Marine, RV, Communications, 600 Volts/30 Amps
DC Common Mode Noise Filter for marine, RV, mobile, portable and fixed station HF operations
The RFI-DC-30 is a common mode noise filter for DC powered equipment up to 30 amps and 600 VDC at 105 degrees C and provides effective dual suppression of common mode current with individual chokes on the positive and negative cables in the HF frequency range from 1-61 MHz (beneficial up to 160 MHz). Very useful for suppressing noise from generators, inverters, battery chargers, solar panels, wind generators, and other noise producing devices sharing the same DC power bus. Simple to install between noise source and noise victim without any modifications to either device.
The enclosure box is a PVC 4″ x 4″ x 2″ weather resistant enclosure with 1/4″ stainless hardware for ease of connection to DC voltage circuits and (optionally) to ground for greater attenuation of the common mode current present on the DC positive and negative lines.
A simple ferrite ring filter on the DC power line can help suppress the RFI noise affecting the victim device or keep the DC power cord from acting as an antenna and radiating RFI into other victim devices. This kit is also useful on laptop computer supplies, routers, cable modems, wireless phone charges, etc.
Installation is quick and easy: Just wrap the DC power cord through the center of the ring filter as many times as you can and reinstall. For best results with long DC power lines, use one at the ring filter at the wall wart end (to prevent the wall wart power supply from using the DC line as an antenna) and another at the DC plug end (to prevent the electronics in the powered device from using the DC power cord as an antenna). Typical installation is shown below:
The filter suppresses RFI in from .1-100 MHz. Inside diameter is 3/4 inch/19 mm.
Since most households and office environments have multiple wall warts we offer the Wall Wart RFI Filter kit in bulk quantity packages.
Known RFI Generators include Roku/Sling-TV power adapter - Interference heard in the AM broadcast band and harmonics. Also many ethernet Cable/DSL modems, cell phone chargers, computer power adapters have the same issue: using the AC or DC side of the power supply as a radiating antenna. RFI solution is to use a linear power supply, change adapters or wall wart ferrite filters