5:1 CUBE™ Unun – Model CU-5-1500 (50:250 Ohm, 1.8-61 MHz, 1.5KW PEP)
Application. For traveling wave, end fed or portable 20-31 foot vertical antennas the 5:1 unun makes a good transformer for converting 50 ohm coax to a 250 ohm feed point. If you use the antenna on multiple bands, the feed point impedance may not always be 250 ohms and use of the unun at high (>350 ohms) or low (<100 ohms) will require reduced power input or the unun may have its power ratings exceeded and damage to the unun may occur. The (5:1 conversion ratio will change for loads other than 250 ohms unbalanced.
Typical application:
Also available as a balanced output – CB-5-1500
50:200 (4:1) CUBE™ Voltage Balun, 1.8-61 MHz, 1.5KW - Carolina Windom, OCF, Loop AntennasProduct DetailsMPN: CB-4-1500Country/Region of Manufacture: USAType: BalunInput ohms/Output ohms: 50 in, 200 outFrequency Range < 2:1 SWR (MHz): 1-31PEP Power Rating (watts): 1500Enclosure Size: 4" x4" x 2"Weight (pounds): 2Antenna Compatability: Dipoles: Extended double zepp, folded 2 wire, off center fed (OCF); Loops: Horizontal, vertical - coax fedAfter many requests we have created a compact, special balun for OCF antennas with vertical radiators. The CB-4-1500ODCV is a CUBE™ enclosure containing a dual core, bifilar wound, voltage balun to force equal voltages on the unequal sides of the off center fed antenna and force current down to the vertical radiator so it acts like a vertical antenna adding to the radiation pattern at low angles for DX.
The vertical radiator is typically 10 feet of 50 ohm coax for the 40 meter long (67 feet at the top) and 22 feet long for the 135 foot OCF.At the bottom of the vertical radiator you should have a line isolator or 1:1 balun (such as the Palomar BA-8E or BA-58E sleeve balun, or CB-1-1500 cube balun) to stop the current on the outside braid of the coax from using the rest of your feedline back to the radio as a long vertical radiator causing RFI and other problems as well as skewing the radiation pattern. The balun can be used with any size.
The balun is rated for full 1500 watts PEP from 1.8Mhz – 61 Mhz and usable to over 150 MHZ! (see graph) The balun can be used with either a 50 or 75 ohm coax vertical radiator and feedline.
The matching line isolator is the MC-1-3000 which should be used at the end of the vertical radiator.
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After many requests we have created a compact, special balun for OCF antennas with vertical radiators. The CB-4-1500ODCV is a CUBE™ enclosure containing a dual core, bifilar wound, voltage balun to force equal voltages on the unequal sides of the off center fed antenna and force current down to the vertical radiator so it acts like a vertical antenna adding to the radiation pattern at low angles for DX.
The vertical radiator is typically 10 feet of 50 ohm coax for the 40 meter long (67 feet at the top) and 22 feet long for the 135 foot OCF.At the bottom of the vertical radiator you should have a line isolator or 1:1 balun (such as the Palomar BA-8E or BA-58E sleeve balun, or CB-1-1500 cube balun) to stop the current on the outside braid of the coax from using the rest of your feedline back to the radio as a long vertical radiator causing RFI and other problems as well as skewing the radiation pattern. The balun can be used with any size.
The balun is rated for full 1500 watts PEP from 1.8Mhz – 61 Mhz and usable to over 150 MHZ! (see graph) The balun can be used with either a 50 or 75 ohm coax vertical radiator and feedline.
The matching line isolator is the MC-1-3000 which should be used at the end of the vertical radiator.
