Name: Elecraft KPA500 HF Linear Amplifier RFI Kit - 5 Filters for RF In/Out, AC Power, PA KEY, Computer Control/AUX/RS232
Brand: Palomar Engineers
SKU: RFI-ELECRAFT-KPA500
Price: 49.95 USD
Availability: InStock

Elecraft KPA500 HF Linear Amplifier RFI Kit - 5 Filters for RF In/Out, AC Power, PA KEY, Computer Control/AUX/RS232

Store/RFI Solution Kits/Radio Communication RFI Solutions/Linear Amplifier RFI Kits

Product Details

MPN: RFI-ELECRAFT-KPA500

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: 5

Typical Use:: AC 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 KPA500 linear amplifier used with the KX3 and similar transceivers.

Included are the following chokes and installation guidelines:

RF Input:F240 ring – 5-9 turns of RG-58 size through center

RF Output:FSB-1 (Big Clamp on) – 3 turns of RG-8 size cable

PA KEY Cable:FSB-1/2 – multiple turns through choke – ½” diameter hole

AC Power Line:F240 ring – 5-6 turns through center

Computer/RS232/AUX Cable:FSB-1/2 – multiple turns through choke – ½” diameter hole

Also make sure you connect a good RF ground to the amplifier ground post.

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).