The unun should find some important applications. Until recently, they have been literally impossible to obtain. But now they can be designed to match 50-ohm cable to loads as small as 3.125 ohms and as high as 800 ohms (both unbalanced loads). They can come in low-power and high-power versions as well as multimatch designs. An important application for ununs is to match 50 ohm cable to the input impedance of ground-fed antennas such as verticals, slopers, inverted L's and towers performing as verticals. Since ground losses play a large role with these systems, a knowledge of the input impedance of the antenna as well as the ground loss is important in determining the optimum impedance ratio. The low-power multimatch unun should find use in the operation room when an unfavorable impedance is presented to the transceiver. Also, a high impedance, multimatch unun can be dasily designed to match 50 ohm cable to the input impedance of beverage antennas. It should also be pointed out that ununs can be employed in series with baluns to provide a host of wideband baluns and ununs with ratios which have been previously unattainable.
Typical Applications: Matching unbalanced 50 ohm coaxial cable to:
Ground fed antennas - shortened verticals, vertical beams, slopers and inverted L's - use 4:1 ratio Ununs model no: UN-12.5 or 9:1 ratio Ununs model no. UN-5.56, etc.
Shunt fed towers performing as verticals - use the 1.56:1 ratio ununs model no: UN-32-18.
HI-Q Antennas - Use UN-32-18. This Unun is specially designed to work with antennas manufactured by Hi-Q.
Matching 75 Ohms Coaxial Cable to a 50 Ohms Coaxial (unbalanced) - use 1.5:1 ratio Unun model no: UN-75.
Matching a Junction of two parallel 50 ohm coaxial cable (resultant impedance of 25 ohms) to a 50 ohms coaxial cable - use 2:1 ratio Unun model no: UN-22-25.
Output of a transceiver when a large VSWR exists on the cable. Depending on coaxial cable's termination at the other end, the cable's impedance at the transceiver end could be different from the cable's normal impedance
Beverage Antennas - Beverage antenna has impedance of 800, 600 or 450 ohms.
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