RF Toroid Calculator by VK3CPU
50:50 ohm (1:1) Common Mode Choke HF Balun Kit - 1500 watt PEP, 1.8-31 MHzProduct DetailsInput ohms/Output ohms: 50 in, 50 outFrequency Range < 2:1 SWR (MHz): 1.8-30PEP Power Rating (watts): 1500Model BA-1-1500 is a 1:1 balun kit used to translate a 50 ohm unbalanced input to 50 ohms unbalanced at power levels up to 1500 watts PEP when used with a matched load. With a matched load the SWR will not exceed 1.5 over the frequency range 1.8 to 30 MHz. 1,500 PEP watt rating on a 25% duty cycle.
The kit consists of a F240 ferrite core, two colors of selected insulated wire, two SO-239 connectors (one for input and one for output connections) with stainless steel hardware, and an illustrated instruction manual with directions to assemble the kit as a 1 to 1 balun (unbalanced coax to balanced antenna/load) or unun (unbalanced to unbalanced). Leave one of the SO-239 connectors off on the output side and connect to your balanced antenna (dipole, beam driven elements, etc). To use as a line isolator/common mode choke, use both SO-239 connectors and insert in series with the coax feed line. For best results use one at the antenna and one for the rig side at the antenna tuner. The number of turns on the toroid can be changed to emphasize the low, mid or high portion of the 160-10 meter bands range as well as the choking impedance (see graph below). Assembly time is about 30 minutes. You can vary the number of turns to emphasize different frequency ranges.
BA-1-1500 Choking Z magnitude – 14 Turns and 10 Turns
Just add your custom enclosure, or optional enclosure box below, with the kit and you have a compete 1:1 current balun/unun.
Tutorials
Model BA-1-1500 is a 1:1 balun kit used to translate a 50 ohm unbalanced input to 50 ohms unbalanced at power levels up to 1500 watts PEP when used with a matched load. With a matched load the SWR will not exceed 1.5 over the frequency range 1.8 to 30 MHz. 1,500 PEP watt rating on a 25% duty cycle.
The kit consists of a F240 ferrite core, two colors of selected insulated wire, two SO-239 connectors (one for input and one for output connections) with stainless steel hardware, and an illustrated instruction manual with directions to assemble the kit as a 1 to 1 balun (unbalanced coax to balanced antenna/load) or unun (unbalanced to unbalanced). Leave one of the SO-239 connectors off on the output side and connect to your balanced antenna (dipole, beam driven elements, etc). To use as a line isolator/common mode choke, use both SO-239 connectors and insert in series with the coax feed line. For best results use one at the antenna and one for the rig side at the antenna tuner. The number of turns on the toroid can be changed to emphasize the low, mid or high portion of the 160-10 meter bands range as well as the choking impedance (see graph below). Assembly time is about 30 minutes. You can vary the number of turns to emphasize different frequency ranges.
BA-1-1500 Choking Z magnitude – 14 Turns and 10 Turns
Just add your custom enclosure, or optional enclosure box below, with the kit and you have a compete 1:1 current balun/unun.
