Do you know Dummy antenna
Dummy antenna is a simple device and very easy to construct.
In radio this device is also known as a dummy antenna or a radio frequency termination. It is a device, usually a resistor, used in place of an antenna to aid in testing a radio transmitter. It is substituted for the antenna while adjusting the transmitter, so that no radio waves are radiated, so that the transmitter does not interfere with other radio transmitters during the adjustments. If a transmitter is tested without a load attached to its output terminals such as an antenna or a dummy load, the power will be reflected back into the transmitter, often overheating and damaging it. Also, if a transmitter is adjusted without a load, it will operate differently as compared with a load, and the adjustments may be incorrect.
The dummy antenna is supposed to simulate the real antenna during alignment. In other words, the idea is that when you unhook your signal generator and hook an antenna back up, the radio will already be aligned for peak performace (more or less!). The dummy antenna is supposed to simulate the impedance of a "typical" antenna, and also terminates the signal generator with a specific impedance. The old repair guides usually show you the schematics and part values of the various dummy antennas.Old car radios are where the dummy antennas usually get used most often. A car radio antenna is a very different impedance than the signal generator's output, and is largely capacitive, so the dummy antenna allows you to align the RF stages as if they were connected to the car antenna.The dummy antenna routine and often use the actual antenna with a loop of wire on the wall to radiate the signal generator's output.
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