AM Broadcast RFI Kits

Elecraft KXPA100 HF Linear Amplifier RFI Kit - 4 Filters for RF In/Out, DC Power, Relay/PTT/Computer Control

SKU RFI-ELECRAFT-KXPA100
$24.95
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Elecraft KXPA100 HF Linear Amplifier RFI Kit - 4 Filters for RF In/Out, DC Power, Relay/PTT/Computer Control
Product Details
MPN: RFI-ELECRAFT-KXPA100
Type: New
Country/Region of Manufacture: United States
Filter Power Rating (PEP watts): coax cable limit
RFI Suppression Range (MHz): 1-300 MHz
# Ferrite Filters: 4
Typical Use:: DC power, RF In/out, I/O control cables

This is a generic linear amplifier RFI kit for DC powered amplifiers. Works on many popular amplifiers including:

Specially designed for the Elecraft KXPA100 linear amplifier used with the KX3 and the Yaesu 817 radio (and others).

Included are the following chokes and installation guidelines:

RF Input: 1/2" Snap on – 2 turns of RG-8X size coax through center (use additional turns if using smaller cable)

RF Output: 3/4" snap on – 3-4 turns of RG-8X size cable (use additional turns if using smaller cable)1/2

Control or Relay Cable: 1/2" snap on – 2-3 turns thru center - ½” diameter hole

DC Power Line: 3/4" snap on – 2-4 turns of +/- DC cables through center

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