50:450 ohm (9:1) Balun or Unun Core Kit, 1.8-30 MHz, 250 watts PEP, end fed, T2FD antenna

Name: 50:450 ohm (9:1) Balun or Unun Core Kit, 1.8-30 MHz, 250 watts PEP, end fed, T2FD antenna
Brand: Palomar Engineers
SKU: BA-9-250
Price: 21.95 USD
Availability: InStock

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

SKU BA-9-250

$21.95

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50:450 ohm (9:1) Balun or Unun Core Kit, 1.8-30 MHz, 250 watts PEP, end fed, T2FD antenna

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

Product Details

Input ohms/Output ohms: 50 in, 450 out

Frequency Range < 2:1 SWR (MHz): 1-31

PEP Power Rating (watts): 250

Model BA-9-250 is a 9:1 balun/unun kit (assembly from parts supplied required) used to translate a 50 ohm input up to 450 ohms at RF power levels up to 250 watts PEP when used with a matched load. With a matched 450 ohm load the SWR over the frequency range 1.8 to 30 MHz is shown in the following table measured with an AIM 4170 network analyzer. Notice that the conversion from 450 to 50 ohms is very consistent from 1-31 MHz and SWR is less than 2:1 over most of the range allowing easy tuning by most radio internal antenna tuners or an external tuner. Graph is for a 9:1 unun often used with long wire or end fed antennas.

Radio Club idea:

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

Typical SWR curve for this project:

TUBE feed line chokes/Line Isolators are used to suppress common mode current carried on the outside of the coax braid which is often responsible for receiver noise and RFI in the receiver/transmitter. These chokes are very useful for suppressing RFI common mode current at the antenna feed point, at 1/4 wavelength intervals along the coax feed line and also at the entrance to the radio station. They are available with various input and output connectors so as to conveniently connect to standard output connectors already installed on your feed line.

Palomar Engineers TUBE feed line chokes are designed to have 2-5 times more choking impedance over a broader frequency range than competitor units in similar packaging. Each choke has the choking impedance and effective frequency range on the product label so you can choose the product best suited for your application.