See Mix Selection for other applications.įor extra large cables use the FB400-31 which has an inside diameter of 3 inches (76mm). Use Mix 61 for VHF and above for RFI/EMI suppression and below 30 Mhz for multi-ratio impedance transformers (baluns/ununs). USE FB102-31 for 4 turns of RG-8X for 16X increase in Z per bead – see pictures below for examples). If you need more Z, just use more beads in series on the cable or use more windings thru a larger ID bead (e.g. Mix 31 has better response below 10 Mhz but above 10 Mhz mix 31 and mix 43 are very close. For 500 ohms we would need 5 mix 31 beads or 6 mix 43 beads to have greater than 500 ohms. For example if you have a 50 ohm RG-8 coax cable and want a choking impedance of 500 ohms at 10 Mhz, you can check the FB102 column (since FB102 will pass RG-8 through its center ID) at 10Mhz and find that Mix 31 has a Z of 108 ohms/bead and Mix 43 has a Z of 91 ohms/bead. Need a smaller power rating but with same, great common mode suppression? Try our 500 watt PEP rated Mini-Choker HERE Production Note: Maxi-Choker may be in Black or White color depending upon available inventory at time of shipment.Īpplication Note: Use impedances for each bead at your desired frequency to select number of beads needed for desired Z. Use the ground lug option for long coax antenna feed lines (over 1/2 wavelength at the operating frequency of any antenna system in the near field of the coax). Use an isolator every 1/2 wavelength for the antenna operating frequency (include velocity factor in calculation). This choke is available with a SO-239 input/output and ground/static bleeder stud (optional) for attachment to a ground rod. These chokes are very useful for suppressing RFI common mode current at the antenna feed point, at 1/2 wavelength intervals along the coax feed line and also at the entrance to the radio station. However, for 7mhz / tropical bands / utilities etc lower in frequency, if you had the room to double the size to 30 feet per side, Id say go for it to improve the lower bands even more. MAXI-CHOKER feed line chokes are used to suppress common mode current carried on the outside of the coax braid which is often responsible for receiver noise and RFI in the receiver/transmitter. The 15-foot square size is ok for me since I like the wide coverage of 160-20m without having 20m directivity go squirrely. 2-5 times more common mode noise rejection, wider bandwidth and higher power then competing filters Available with ground stud/static bleeder option for solving tough RFI issues - Available with dual stud/wingnut output for ladder line interface - Works for all coax fed antennas from 1.8-61 MHz (160-6 meters) - excellent for multi-band beams, verticals, dipoles and highly unbalanced off center fed antennas. MAXI-CHOKER Features: - Uses proprietary Multi-Mix, Multi-Core, Multi-Turn(TM) ferrite technology for maximum choking (up to -48 dB common mode noise rejection) and maximum bandwidth - Choose 3 KW PEP or 5KW PEP for heavy duty digital modes up to legal limit, 50 ohm SO-239 connectors In/Out, 1-61 MHz, usable to 100 MHz - Suppresses transmitter coax feed line radiation when installed at antenna feed point or reduces common mode receiver "noise" when installed at radio end of coax.
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