A duplexer is a device used in radio communication systems that enables two-way communication on a single frequency. In GMRS communication, you can boost range & enhance the system by setting up a repeater using the best GMRS duplexer.
It works by separating the transmit and receive signals, allowing a radio to both Tx and Rx signals on the same frequency without interference.
This is achieved by routing the transmitted signal to the GMRS antenna and isolating the received signal from the antenna, thus ensuring that the transmitted signal does not interfere with the receiver.
Duplexers are commonly used in GMRS radio repeater systems to improve the efficiency and performance of the radio by eliminating cross-talk between transmit and receive signals.
When & where to use a GMRS duplexer?
A GMRS duplexer is used in radio communication systems that require two-way communication on a single frequency, specifically for GMRS radios. Some common applications of GMRS duplexers include:
Mobile and base GMRS radio systems: A GMRS duplexer is used in mobile and base GMRS radio systems to improve the efficiency and performance of the radio by eliminating cross-talk between the transmit and receive signals.
GMRS repeater systems: A GMRS duplexer is used in GMRS repeater systems to allow a single antenna to be shared by a transmitter and a receiver, allowing the repeater to receive a signal on one frequency and simultaneously retransmit it on another frequency.
GMRS emergency communications: GMRS duplexers are used in GMRS emergency communications, allowing emergency responders to communicate effectively in the field.
A GMRS duplexer can be used in any GMRS radio communication system that requires two-way communication on a single frequency and wants to improve the efficiency and performance of the radio.
Types of GMRS Duplexer
There are three types of GMRS duplexers available in the present market. Those are:
Cavity duplexer: A cavity duplexer is a type of passive duplexer that uses resonant cavities to separate the transmit and receive signals.
It works by routing the transmitted signal to the antenna and isolating the received signal from the antenna, effectively preventing the transmitted signal from interfering with the receiver.
Filter duplexer: A filter duplexer uses filters to separate the transmit and receive signals. It works by passing the received signal through a low-pass filter and the transmitted signal through a high-pass filter.
This effectively isolates the two signals, preventing interference between the transmitter and the receiver.
Hybrid duplexer: A hybrid duplexer combines the principles of cavity and filter duplexers to separate the transmit and receive signals.
It uses resonant cavities and filters to isolate the transmitted and received signals, improving the performance and efficiency of the radio.
Each type has own advantages and disadvantages. The type of duplexer used in a GMRS system will depend on the specific requirements of the system and the environment in which it will be used.
Recommended GMRS Duplexers – Top Picks
If you are going to setting up a GMRS repeater, then you can try this duplexer without any hesitation. Though I liked this device most but I suggest you to research more before purchase.
Fumei UHF 50W Duplexer
The Fumei UHF Duplexer is designed for use in two-way radio communication systems operating in the UHF frequency band and it is adjustable within the range of 400-470 MHz, and with the proper tools, you can easily make the necessary tuning adjustments.
This duplexer has been pre-configured by the factory with a low frequency of 462 MHz, a high frequency of 467 MHz, and an N female connector type. As a result, building a repeater is now effortless.”
It is used in GMRS and other types of radio repeater systems to improve the efficiency and performance of the system by separating the transmit and receive signals, allowing the radio to both transmit and receive on the same frequency without interference.
The duplexer is rated for a maximum power output of 50 watts, making it suitable for use with high-power transmitters. It is also designed to operate over a wide temperature range, ensuring reliable performance in a variety of environments.
The duplexer is constructed with high-quality components, ensuring durability and long-lasting performance. It uses a hybrid design that combines the principles of cavity and filter duplexers to separate the transmit and receive signals.
This design provides improved performance and efficiency compared to other types of duplexers. The duplexer is easy to install and requires no tuning, making it a cost-effective solution for GMRS and other radio communication systems.
Features of Fumei Duplexer I Liked:
- This duplexer boasts a maximum input power of 50W.
- Operates within a frequency range of 400-470 MHz.
- With a low isolation loss of less than 1 dB, and a V.S.W.R. of less than 1.3.
- The duplexer boasts an isolation level of over 80 dB and a suppression level of over 80 dB.
- It features an impedance of 50Ω and capable to operate within a temperature range of -25℃ to +55℃.
Conclusion: The Fumei UHF Duplexer is a reliable and efficient device designed to improve the performance of GMRS repeater systems.
Its hybrid design, high-power rating, and wide temperature range make it a versatile solution for GMRS and other types of radio communication systems.
If you are looking for a cost-effective and easy-to-install duplexer for your GMRS repeater, the Fumei Duplexer is a great choice.
Sanpyl SGQ-450D Duplexer
The Sanpyl SGQ-450D is a UHF duplexer designed for use in two-way radio communication systems. The 50W 6 Cavity UHF Duplexer with its multiple stop-band filter tool is a compact and easy-to-install.
This duplexer designed to enhance wireless communication in large areas such as residential areas, shopping malls, hotels, and more. Its minimum transmission and reception frequency difference is 3 MHz, while the maximum difference is 10 MHz.
With an isolation level of over 75 dB, this duplexer ensures high sensitivity in both signal receiving and transmitting, delivering reliable performance.
It operates at a transmission frequency of 455.175 MHz and a reception frequency of 465.175 MHz, with a bandwidth of ±500 kHz. The standard terminal is an N connector and the frequency interval is 8 to 10 MHz.
The duplexer has an insertion loss of 1.0 dB and a nominal impedance of 50Ω. It provides a high level of isolation and inhibition, with values of over 75 dB, making it ideal for reliable signal transmission and reception.
The operating temperature range is 25 to 55 degrees Celsius and it can withstand relative humidity levels between 5% and 95%.”
How a Duplexer Works in GMRS Repeater?
In a GMRS repeater system, a duplexer mainly works with Rx and Tx signals. Here’s how it works:
Receiving: When the repeater receives a signal, the duplexer routes the received signal from the antenna to the receiver. The receiver then amplifies and processes the signal, preparing it for re-transmission.
Transmitting: When the repeater is ready to transmit, the duplexer isolates the receiver from the antenna, allowing the transmitter to send its signal to the antenna without interference. The transmitted signal is then broadcasted to other radios in the area.
Final Words
Now I hope that you have a details idea on GMRS duplexer to use in repeater. The duplexer essentially acts as a switch, alternately connecting the transmitter and the receiver to the antenna and isolating one from the other.
This allows the GMRS repeater system to provide continuous two-way communication on a single frequency. Hopefully you will able to select the perfect duplexer for your GMRS repeater after reading this article.
Hi, I am Jeff, a dedicated author in radiothoughts.com and sharing my own experience on the field of electronics and radio communication engineering. I am also checking facts for other published articles here.
I love to learn the latest technologies on radio communication and write here about that to help readers to be up-to-date. I have used a lot of radios, electronics, and communication devices. Now I can easily advice to beginners or learners regarding different radios.