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.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
Iron powder cores are more stable than ferrites and do not saturate as easily so they are best for tuned circuits, filters, and high power inductors. They come in different “Mixes” for use at different frequencies. For best “Q” use the Mix specified for your frequency.To find the number of turns to give the desired inductance for your coil use the formula below:
Turns = 100 x 
Toroid Dimensions
To order specify core size and mix (e.g. T200A-2). Available in sizes that have µH per 100 turns shown in table.
All iron powder cores are special orders. Please allow one week for shipment after order received.
The iron powder cores shown in the above tables are primarily used for either high power feed line chokes for common mode current reduction or for 4:1 and 9;1 very high power transmission line transformers.
For high power feed line chokes, choose the inside diameter of the iron powder core closest to the transmission line outside diameter and use 6-20 cores at the junction with the antenna feed.
For 4:1 (50/200 or 75/300 ohm) transmission line transformers in the range of 1.8-30 Mhz, select the size appropriate for the power level as follows:
T200A x 2 = 1.5KW
T300A x 2 = 2.5KW
T400A x 2 = 5KW
Use Mix 2 for all the above transmission line transformers. Fully assembled and enclosed units are available for each of the power levels. Click HERE for information.
4:1 transmission line transformers using iron powder cores are typically used for ladder line to 50 ohm coax connections
For .1 – 2 Mhz wide band transformers use Mix 26 which has a higher permeability and requires less turns to achieve a given inductance. Mix 2 has almost constant permeability from 1-30 Mhz. Mix 26 has an initial permeability of 75 at .1 Mhz and gradually decreases to about 10 at 30 Mhz. For high power AM broadcast range (.5-1.7 Mhz) transformer, use Mix 26 to reduce the turn count.
Minimum order for iron powder cores is $50
Shipping on larger cores in quantity may be more than $10 – email/call for quote.