Broadband, Non-Inductive Termination Resistor load used on many terminated antenna types such as T2FD, Broadband Terminated Dipole (BBTD), Rhombics and others
Resistive Value: 1000 ohms (+/- 10%)
SSB (25% duty cycle) rating in Watts: 600
CW/FT8 (50% duty cycle) in watts: 300
Length (tip to tip) Inches: 14"
Width inches: 3"
Inductance < 20 nH (1-61 MHz)
Internal Resistance Wattage: 200 watts
you can use 2 of the 1000 ohm resistors in parallel to yield 500 ohms total and double the power at 1200 watts. Perfect for high power antennas with 9:1 transformers requiring 500 ohm termination resistance total.
Excellent Install of BBTD by K1FU
Delivery Note (2/15/2023) - we are currently out of stock but will have more in stock around April 1, 2023. You can order now to get in the queue for the next 100 resistors.
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 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).
F240-77 Choking Impedance in AM Broadcast Band
Typical Installations for Donut/Ring Toroids
 AC Cable on F-240 Toroid – 6 turns |
 Ethernet Cable on F-240 Toroid – 7 turns |
 Audio or Mic cable on F240- 12 turns |
Extra Mix 75 Snap On Beads HERE – VERY effective for AM Broadcast RFI