PURPOSE
These kits are designed to choke common mode currents going into or exiting from your amplifier cables.Filters are supplied for the RF In, RF Out, Relay Cable/control lines, and AC power line.Use of the filters often helps cure SWR problems between amp exciter and amp and between amp and antenna tuner or direct to antenna.The AC power line choke helps keep common mode current out of the power line which could cause interference to other devices connected to the same power line if not suppressed.
USE
Standard kit for amplifiers with single input, single output, relay keying and AC input
Deluxe Kit for amplifiers with dual inputs/outputs, frequency/keying control lines
KIT INCLUDES
|
Filter Type |
Usage |
Standard Kit |
Deluxe kit |
|
F240 Ring (1.4” ID) |
RF Exciter input |
1 |
2 |
|
Snap On (1/2” ID) |
Ethernet, PTT control |
2 |
2 |
|
Snap On (1” ID) |
RF Output |
1 |
2 |
|
Snap On (1” ID) |
120/240 VAC Input |
1 |
1 |
|
Total Filters |
5 |
7 |
INSTALLATION GUIDELINES
Standard Kit - Part# RFI-LA-FLEX-1
RF Input:Ring Filter (1.4” ID) – 5-9 turns of RG-58/8X size through center
RF Output:Snap On Filter (1” ID) – 3 turns of coax cable through center
PTT Relay Cable:Snap On Filter (1/2” ID) – multiple turns through center
Ethernet Cable:Snap On Filter (1/2” ID) – multiple turns through center
AC Power:Snap On Filter (1” ID) – 3 turns of power cord through center
Deluxe Kit - Part# RFI-LA-FLEX-2
RF Input (2)Ring Filter (1.4” ID) – 5-9 turns of RG-58/8X size through center
RF Output: (2)Snap On Filter (1” ID) – 3 turns of coax cable through center
PTT Relay Cable:Snap On Filter (1/2” ID) – multiple turns through center
Ethernet Cable:Snap On Filter (1/2” ID) – multiple turns through center
AC Power:Snap On Filter (1” ID) – 3 turns of power cord through center
Also make sure you connect a good RF ground to the amplifier ground post.
Often it is difficult to slip beads on a cable because of a plug or connector. Split beads solve this problem. They come in two halves that fit over the cable. A plastic snap cover holds the two halves together and holds the assembly on the cable.
For RFI use, mix 31 is effective from 1-300 Mhz, mix 43 works from 20-250 Mhz, Mix 61 is for 200-2000 Mhz, and mix 77 favors .1-20 MHz. These frequencies are those of the interfering signal to be eliminated, not the operating frequencies of the equipment to be protected.
Not sure of what sizes you need or solving a RFI problem with devices using multiple size cables? Try the Ferrite Snap On Combo Pack which has sizes from 1/4″ to 3/4″ with either Mix 31 (1-300 MHz) or Mix 61 (200-2000 MHz) or Mix 75 (150 KHz – 10 MHz).
NOW WITH QUANTITY PRICING FOR CLUB , VOLUME PURCHASERS!
Bead dimensions are shown in the picture below and in the table as A, B, C
Ferrite Split Bead Dimensions
Application Notes
Application Note for using these Snap On split beads: How Many Chokes do I need?
You can very effectively increase the choking impedance of smaller cable by using a large hole ferrite bead and wrapping the cable through several times. For particularly difficult common mode current/RFI problems you may need a choking impedance as high as 5-10K ohms. Using multiple beads and multiple turns through each bead will give higher impedances up to a point. At higher frequencies, when the number of turns approaches an electrical wavelength, the choke becomes resonant due to stray capacitance and the inductance of the cable and limits the high end impedance values to less than the above table points.
Some example of ways to wrap cable are shown below.
 FSB-1/4 – 1 turn |
 FSB-1/2 1 turn |
 FSB-1/2 Open Shell |
 FSB-1/2 2 turns |
 FSB-1/2 3 turns |
 FSB-1/2 4 turns |
—–//—–
More examples of split bead use
Ethernet Cable on FSB-1/4
Ethernet Cable on FSB-1/2 – 3 turns for 9X Impedance good filter for 15-30 mhz between 2K-3K ohms choking Z
Three Effective Radio Interference Filters
 FSB-1/4 or FSB-1/2 4 turns for 14-50 Mhz 2K-3K Z |
 FSB-1/2-5 turns for 10-30 Mhz 2K-4.5K choking Z |
 FT240-43 – 14 turns for 3-14 Mhz or use two FT240-43 for 1.8-10 Mhz |
These snap-on chokes are useful for reducing RFI in public address system amplifiers, speaker wires, mic cables, mixer panels, coax cable, telephone wires, computer sound card speakers, dsl/cable connections, remote control heads for ham transceivers (Especially FT-100, FT900, IC-706, IC-7000), AC power cables, DC power cables, home theater cables, video cables, HI Fi cables, guitar amps, linear amp cables, etc.
They are also helpful in suppressing common mode noise/RFI in radio and TV receivers, audio and RF amplifiers. They can also help suppress noise generated by treadmills, exercise equipment, fish tank heaters, oil heater pumps, fluorescent lights, motors, cable modems, DSL modems, computers, and many other electrical devices. Common mode current reduction in computer cables often helps speed up computers.