The way to build a radio repeater is very useful for correcting communication problems. But, do you need to build one for your project? Or do you need suitable information on the radio repeater for your design project?
How to Build a Radio Repeater
There are two types of radio repeaters which are the simplex and ham radio repeater. Here, we will focus on how to build a simple simplex repeater.
Simplex radio repeater is an easy and economical project that you need to interface with a transceiver. Fortunately, the simplex radio repeater is easy to interface with most transceivers. The best part is that you can build this project with readily available parts. With that in mind, let's look at the components needed for this project.
Components
Semiconductors
U1-SD1000A Voice Record/Playback IC (RS 276-1325)
U2-7805 5V voltage regulator
U3-74LSOO quad NAND gate IC
U4-74LS74 double D flip-flop IC
Transistors Q1, Q2-2N3904 NPN
Resistors (All fixed resistors are 1/4 watt, 5% units):
Ohm potentiometer R1-1K
R2-15K ohm
R3-1K ohm
R4-2.2K ohm
R5, R8-4.7K ohm
R6, R7-20K ohm
Capacitors:
Capacitor C1, C2, C3, C4, C5, C6-Q.22-~F (RS 272-1070)
Electrolytic capacitor C7 -220-~F (AS 272-1029)
Connectors
Welding
Soldering Iron
Breadboard
Power supply
Steps
Here's how to create this simple simplex portable repeater in three steps:
Step 1: Design
Simplex Radio Repeater Diagram
Point J1 is the input of the radio's COS signal. For you to receive an audio signal, the COS signal needs to be greater than 0.7v.
Additionally, this switches the transistor (Q2) to ground. When this happens, the U1's play/record pin goes low and puts the U1 into record mode.
You can configure NAND gates (U3B and U3C) as your inverters for high output generation.
Then configure your potentiometer (R1) so that you can control the volume of the audio output signal.
U2 in this build is a 5v regulator. You can use it to allow connections to various unregulated DC supplies ranging from 7v to 12v.
On the other hand, you can connect a regulated 5v power supply to the Vcc points of your build to eliminate the need for a U2.
Step 2: Interface
Then interface your simplex radio repeater to radio by connecting the six input/output pins in the following order:
Connect J1 (COS) to the squelch operated by the radio carrier. That said, it should give you a value greater than 0.7v if you have a carrier and less than 0.7v if you don't have a carrier.
Connect J2 (Vcc) to an unregulated DC input that ranges from 7v to 12v
Connect J3 (audio out) to the radio's audio input. While you are doing this, be sure to adjust the volume of R1 to an acceptable level
Ground J4 (push-to-talk) of the radio to the transmitter key. This way you can control your broadcasts
Connect J5 (audio-in) to the radio output
Connect J6 (GND) to radio ground
Step 3: Finish
Finally, you can power up your simplex repeater and prepare it for emergency radio coverage or use situations.
Final Words
Overall, radio repeater is essential to the recent advancement of radio technology. Helps provide accurate, audible signals from one point to another when there is inadequate radio coverage. So if you've ever wondered how people communicate over great distances, here's your answer: the radio repeater.
That wraps up everything you need to know about radio repeaters and how to make one. If you have problems directly interfacing your simplex receiver to the radio, try obtaining interfacing hardware to correct the problem.