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What is 75 ohm coaxial cable used for?
Cables with 75 Ohm are mostly used for video signals, while 50 Ohm cables tend to be used for data and wireless communications. In coaxial cables, Ohm refers to the impedance, which is the measure of resistance in the cable to the flow of electrical energy.
Can you use 75 ohm coax ham radio?
Generally you can use 75 ohm cable in any amateur radio application which uses 50 ohm cable. Now there are a very few applications, like matching sections, that this doesn’t work. However, in at least 95 percent of the cases 75 ohm cable works fine.
How is the impedance reflected on a 75 ohm antenna?
The impedance of the far end will be reflected on the near end. Thus our 50 ohm antenna at the other end of the 75 ohm will appear as 50 ohms to the transmitter. This will only happen on one frequency, but will be close enough to cover most of a ham band.
How to do impedance matching with coaxial transmission lines?
The way to do that is to parallel an inductive reactance of 25.34 at that same point. The reactances will cancel each other out, and you are left with 51 ohms of pure resistance at 5.357 MHz. So, install a 50 ohm coax that is 16.16 ft long, then insert a tee at that point.
Can a 50 ohm antenna cover 75 ohms?
Thus our 50 ohm antenna at the other end of the 75 ohm will appear as 50 ohms to the transmitter. This will only happen on one frequency, but will be close enough to cover most of a ham band. To start out, lay out your coax to the proposed length but make it longer than it needs to be to reach your destination.
When to use 50 ohm or 75 ohm cable?
The special case where the feed line is a multiple of a half wavelength can be used to advantage when the antenna and feed line are of different impedances. The impedance of the far end will be reflected on the near end. Thus our 50 ohm antenna at the other end of the 75 ohm will appear as 50 ohms to the transmitter.