… What are Transmitters, Receivers & Antennas on Two-Way Radios? … over …

How do you define what a transmitter does compared to what a receiver does? Let’s examine this a little bit closer as we explore what each function really does…

Two-Way Radio Transmitter:

• The transmitter generates a radio signal or wave.
• Key components include:
  • Oscillator: Creates the carrier frequency.
  • Frequency Multipliers: Boost the frequency to the final output.
  • Power Amplifiers: Amplify the signal to reach the antenna.
• The output frequency is called the carrier, which can change based on amplitude or phase modulation.
• Amplitude Modulation (AM) and Frequency Modulation (FM) have distinct characteristics, with FM being less susceptible to interference from RF noise.

Two-Way Radio Receiver:

• The receiver complements the transmitter.
• Its tasks involve:
  • Receiving the modulated carrier.
  • Processing the signal.
  • Sending it to a detector station.
  • Stripping off the modulation to restore original information.
• Most radio systems operate with AM or FM.
• A microphone inputs information, and a loudspeaker outputs the received signal.
• Signals are typically analog, but some systems use binary signals (e.g., frequency shift keying) for data transmission.

Digital Signals and Morse Code:

• Digital signals pose challenges for human interpretation due to our analog world.
• Morse Code, based on ones and zeros, is an exception.
• When using digital radio, a digital-to-analog converter is essential for human communication.

Squelch Circuits in Receivers:

• Receivers often feature squelch circuits:
  • Turn off output when no signal is detected to prevent continuous noise.
  • Allow properly coded signals to pass through.
  • Common schemes include CDCSS (continuous digital-coded squelch system) and CTCSS (continuous tone-coded squelch system).

Two-Way Radio Antennas:

• Antennas play a crucial role:
  • Transmit the radio signal into space.
  • Enable the receiver to pick up energy.
• Lower frequency channels require larger antennas for better communication.
• Antenna height significantly impacts overall coverage.
• Dipole antennas (wire or rigid metal rods) have lengths based on half the wavelength of the carrier frequency.
• Antennas can be vertically or horizontally polarized; most mobile systems use vertical polarization.

In summary, the transmitter, receiver, and antenna together create an effective two-way radio communication system. 📻🔊🌐