Principles of Direction Finder Operation

Principles Direction

As you can see in the block diagram of a simple direction finder, the three basic units of a direction finder are a directional antenna, a radio receiver, and an indicator. Antennas. Two simple antennas which qualify as directional antennas are the loop antenna and the U-antenna. Such antennas have a directional response pattern which takes the form of a figure 8, as you can see in the illustration above. When a radio wave arrives at right angles to the plane of the two vertical arms of the...

Operational Analysis Of Receiver Rtrc

R19 Trc1 Receiver

Notice the front view of receiver R-19 TRC1 which illustrates the controls on the front panel. At the upper left corner are the receiver output terminals used in four-wire radio remote control to connect the high fidelity output to a remote control unit. Most of the other controls at the left of the control panel concern the AC power circuit. The AC line brings power into the receiver. The PUSH FOR LINE CHECK switch can be used when the meter switch, at lower center of the panel, is on position...

Air Force Receiver BC

348 Receiver

This receiver has the usual stages of a communications receiver, as you can see in the diagram at the right. The BFO is combined with the second IF in a single stage with a single tube for both circuits. Another single tube combines the third IF, detector, and AVC circuits. Notice the bench installation of the receiver on page 78. Here, the receiver is associated with an autotune transmitter shown at the Bench Installation of Receiver BC-348 right. The main tuning dial is at the upper center of...

Principles Of Superheterodyne Operation

The superheterodyne receiver takes advantage of two important facts of radio operation. First, amplification of a radio signal at a low frequency can be more successful than amplification at a high frequency. Second, amplification of a signal by fixed tuned circuits is more successful than amplification by variable tuned circuits. The superheterodyne converts all input frequencies to a single, fixed, lower frequency which is amplified by fixed tuned circuits. This process distinguishes the...