5000 Watt rated 1:1 CUBE UNUN™
This higher power UNUN utilizes mil-spec coax cable for the windings on a extra large core toroid with coax silver shield and silver braid for low loss. The dielectric is Teflon® insulation for high voltage ratings of 1,900 volts. (A typical 5KW signal at 50 ohms impedance will have a voltage of 500 volts at 1:1 SWR). Wired as a UNUN (CU-1-5000) with SO-239 input and output connectors. Rated 5KW PEP/1500 Watts AM/RTTY/CW from 1.8-30 Mhz, less at 50 Mhz.
If you run RTTY contests or FT8 at 1500 watts output, this is the balun/unun you need – it won’t burn out at heavy 1500 watt duty cycles like other brands rated at 1500 watts (or more). We use these same chokes in our own RTTY station at full 1500 watts output and they have never failed. We use one at the amplifier output and another at each antenna feed point. Works very well on OCF antennas below the 4:1 balun to keep RF current on the antenna and off the feed line. Built like a tank, works like a charm, and priced under the competition – what more can you ask for? THIS IS OUR MOST POPULAR HIGH POWER UNUN!
Choose optional ground lug (on input connector shield) and static bleeder (on input connector center conductor) to bleed off static charges on a continuous basis. (Not a lightening arrestor)
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