AM Broadcast RFI Kits

MINI-BALUN 4:1 Coax Interface to Ladder Line, Loop, OCF antennas 500 Watts PEP, 1-61 MHz

SKU MB-4-500SS
$69.95
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MINI-BALUN 4:1 Coax Interface to Ladder Line, Loop, OCF antennas 500 Watts PEP, 1-61 MHz
Product Details
Brand: Palomar Engineers
MPN: MB-4-500TS
Country/Region of Manufacture: United States
Effective Frequency Range (MHz): 1-60
PEP Power Rating (watts): 500 SSB (25% duty cycle), 250 Watts CW/FT8 (50% duty cycle)
Estimated Insertion Loss (db): .25 db
Input Connector Type: SO-239 female
Output Connector Connector Type: Dual 1/4" stainless steel studs
Enclosure Size (LxWxH inches): 3" long, 2 in wide, 1.25" high

MINI-BALUN Features:

- Uses proprietary Multi-Turn, Multi-Ferrite technology for maximum power transfer and minimum SWR

- 500 Watts PEP, 50 ohm SO-239 connectors In, Dual Side Stud Output, 1-61 MHz (usable to 100 MHz) - AKA 4:1 BALUN

- Works for coax fed antennas from 1.8-61 MHz (160-6 meters) - excellent for multi-band loops, OCF, G5RV/ZS6BKW or Flag Pole OCF antennas fed with ladder line.

- 2-5 times more wider bandwidth and higher power then competing baluns of similar power ratings


This balun has a SO-239 input and 1/4" side studs output.

For Higher Power needs use our CB-4-1500TS or CB-4-5000TS







When considering solutions for AM broadcast (550 Khz – 1.8 Mhz) you should consider Mix 77 ferrites available in a variety of shapes and sizes.  Choose a size to give the maximum number of turns of the affected wire or cable.

AM broadcast transmits on a low frequency with large antennas.  Consequently it takes a large antenna to receive the signals.  Typical “antennas” are AC house wiring, phone lines, long satellite or cable TV cables, DSL/CAT5 lines running between rooms, etc.  The device wires that connect to these  “antennas” need to be choked with as many turns through the ferrite as possible.  Some installation examples are shown below on this page.

For AC/ DC power cords and coax cables the F240-77 (2.4″ OD, 1.4″ ID) “Donut” toroid is the most popular.  Also available are smaller toroid donuts and Mix 77 beads. Shown below is a graph with 8, 10, and 12 turns through the toroid – obviously more turns has higher choking impedance.  Mix 77 toroid products are HERE and Mix 77 small beads (for small wires) are HERE

F240 77 Turns Comparison 1024x648 - AM Broadcast RFI Kits

F240-77 Turns Comparison from .1 – 8.1 Mhz

Shown below is a graph of frequency response verses choking magnitude for a F240-77 in the AM Broadcast band for a 12 turn coil around the toroid. (Same info as above but different frequency range).

AM Band Choking Graph F240 77 1024x648 - AM Broadcast RFI Kits

F240-77 Choking Impedance in AM Broadcast Band

 

 

Typical Installations for Donut/Ring Toroids

20131210 114716 150x150 - AM Broadcast RFI Kits

AC Cable on F-240 Toroid – 6 turns

20131210 115137 150x150 - AM Broadcast RFI Kits

Ethernet Cable on F-240 Toroid – 7 turns

20131222 125533 150x150 - AM Broadcast RFI Kits

Audio or Mic cable on F240- 12 turns

 

 Extra Mix 75 Snap On Beads  HERE – VERY effective for AM Broadcast RFI