Palomar Engineers provides a variety of Radio Frequency Interference (RFI) and Electro-Magnetic Interference (EMI) solutions from 100 KHz to 1000 MHz. We have many RFI solution kits targeting common RFI problems encountered by consumers, broadcast professionals, radio operators, industrial plant managers, marine/ship operators, solar power contractors, etc. For custom individual RFI problems we offer individual ferrite RFI suppression components in bead, snap on and ring topology to fit various wire/cable configurations for AC/DC power cables, coaxial feed line, and device interconnect cables. Different ferrite mixes suppress different frequency ranges. To select a mix for your interfering frequency see: Choosing a Ferrite Mix To learn about using ferrites for RFI/EMI suppression check out : RFI Tutorial Center Get a Copy of Ham Radio RFI Cheet Sheet for all your communication RFI issues! If you need additional help call 760-747-3343 or email Sales@Palomar-Engineers.com describing your problem.RFI Solution Kits
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.