50:450 ohm (9:1) Balun or Unun Core Kit, .5-32 MHz, 1000 watts PEP, end fed/Ladder Line, T2FD antenna

Name: 50:450 ohm (9:1) Balun or Unun Core Kit, .5-32 MHz, 1000 watts PEP, end fed/Ladder Line, T2FD antenna
Brand: Palomar Engineers
SKU: BA-9-1000
Price: 29.95 USD
Availability: InStock

Store/Antenna Products/CUBE Impedance Transformers (<1:1, 1:1, >1:1)/50:450 ohm (9:1) Transformers

SKU BA-9-1000

$29.95

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50:450 ohm (9:1) Balun or Unun Core Kit, .5-32 MHz, 1000 watts PEP, end fed/Ladder Line, T2FD antenna

Store/Antenna Products/CUBE Impedance Transformers (<1:1, 1:1, >1:1)/50:450 ohm (9:1) Transformers

Product Details

MPN: BA-9-1000

Type: balun or unun

Input ohms/Output ohms: 50 in, 450 out

Frequency Range < 2:1 SWR (MHz): .5-32

PEP Power Rating (watts): 1000 Watts PEP

Antenna Compatability: Unun: End fed, Balun: Ladder line

Purpose. Model BA-9-1000 is a 9:1 balun/unun kit (assembly required from parts supplied) used to translate a 50 ohm input up to 450 ohms at RF power levels up to 1000 watts when used with a matched load. It provides conversion from unbalanced coax to balanced ladder line/antenna feed point and gives a 9:1 impedance step-up to reduce SWR on the coax. Place at the junction of the balanced line and the coax to convert from balanced line to unbalanced coax.It can also be wired as an UNUN with unbalanced coax input to unbalanced output such as an end fed antenna.

KIT Contents. The kit consists of a F240-61 ferrite toroidal core, three colors of insulated wire, a SO-239 UHF connector with stainless steel hardware, and an instruction manual.

Assembly time: About 1 hour

Radio Club idea:

Buy 10 for a club do it yourself construction project - you can learn something and also build an end fed antenna (just add wire).

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).