When reading a transceiver schematic, you should first recognize that it has graphic symbols representing electronic and electrical components. What can be seen most often in a transceiver schematic are lines corresponding to actual wires or traces of copper conductors on a printed circuit board. You may also check out detailed references that show pictures of electronic and electrical parts, and their equivalent schematic symbols, which are interconnected into circuit stages. After learning about circuit stages, you could get familiar with the different types of transceivers.
The transceiver is made up of a transmitter and a receiver. A transceiver schematic may be drawn either on a single page or on several pages. If drawn on several pages, there will be labels on edges of the schematic indicating connection to other pages. For instance, “+Vcc” is a common positive direct current (DC) supply voltage. The negative side of the power supply is usually indicated by a small triangle with one tip pointing downward.
A transmitter schematic indicates a stage usually with a crystal oscillator circuit, which is the frequency reference that controls the carrier generator for the transmitter. Very simple transmitters have one crystal-controlled stage that operates on a single frequency. Multiple-frequency transmitters usually employ one reference crystal with an integrated circuit that usually synthesizes the various frequencies for a multiple-channel transmitter. The transmitter needs to have a fairly accurate crystal to make sure remote receivers will find the carrier it is sending out.
Schematic symbols are accompanied by a single letter or a single identifier followed by a number. A resistor may be labeled as “R1,” a transistor as “Q1,” an integrated circuit as “IC1” or “U1,” and a capacitor as “C1.” A transceiver schematic also has abbreviations such as power supply unit (PSU), local oscillator (LO), receiver (RCVR), transmit (TX), crystal (XTAL), and many others.
You will have many options when buying a transceiver. Standard transceivers can be placed on a desk, such as a base transceiver, while handheld transceivers are portable transceivers. Making a transceiver can be an interesting hobby. In the early days of radio, hobbyists and enthusiasts had fun building the electronics as well as the cabling for the antenna system. Usually, the bigger the antenna, the farther is the range of the signal.
When using a transceiver, you have to know the needed receiver frequency and be able to set it on the transceiver. Digital controls allow the frequency to be preset. This way, you can select the right frequency to listen to or monitor.