Standard BPF for 2 way radio design

RF Filter and Duplexer for Two-way Radio isolate interference – TEMWELL TEMSTRON

Two-way radio unlike cell phone, it is a radio that can operate two ways, transmit and receive radio signals, without the need for the recipient to take action, commonly called a transceiver. It can work in half-duplex or full duplex mode. Half-duplex allows the radio to transmit or receive in turn but not both simultaneously. Full-duplex allows the radio to transmit and receive at the same time.

The useful features and typical applications of two-way radio as following:
★It is not dependent on cell towers or phone lines, easy to operate
★Available in stationary base station, and hand-held portable devices such as walkie-talkie
★No monthly maintenance fees or related recurring costs
★GPS or indoor location tracking
★Fire alarm integration, to link your buildings fire alarm with your radio system
★Man down, which dispatches an automatic call or emergency alarm for helping radio users when they are injured or fall unconscious.
★For work environments that require instant voice communication between multiple parties, such as airport controller, ship captain, public safe emergency services personnel (e.g. fireman, policeman, and ambulance paramedic), taxi, soldier and military unit, fast food and warehouse employee, and radio amateur etc.

The traditional analogue service is no longer to meet the users' needs completely. The evolution of digital technology by time, nowadays the well-know type is digital two-way radios. To digitize voice communications, converting sound voice into the same kinds of letters and numbers as the data on a computer. ETSI produces the applicable standard DMR (digital mobile radio) as direct replacement for analogue LMR or PMR (land / private mobile radio) firstly, and dPMR (digital private mobile radio) has been developed by ETSI subsequently.

Digital two-radio frequency bands sort by unlicensed in 446 MHz band and conventional in LMR or trunked bands from 30 to 1000 MHz. The particular bands are:
★VHF Band (70 to 87 MHz, 146 to 174 MHz): typically used by older radio systems require coverage in wide geographical areas, and require interoperability with marine frequencies, great for outdoor coverage.
★UHF Band (370 or 380 to 400 MHz, 450 to 520 MHz): very common bands for public safety agencies and trunked radios as like Terrestrial Trunked Radio (TETRA), Tetrapol and Next Generation Digital Narrowband (NXDN). It gives good performance both outdoor and indoor.
★700 MHz (763 to 775 MHz, 793 to 805 MHz): It is the recent addition to the public safety frequency in US. About 10% of jurisdictions use this band for voice communications.
★800 MHz (806 to 815 MHz, 851 to 860 MHz): It is the newer band used for public safety systems in US, mostly trunked radio systems. It has good indoor coverage, but not as good outdoor range as UHF and VHF.

TEMWELL designed and manufactured special RF Bandpass Filter used to ensure digital two-way radio frequencies does not over-deviate into adjacent bands, and avoided signals noise or interference. The following models table is 5 featured frequencies, 70 MHz, 140 MHz, 160 MHz, 180 MHz and 460 MHz. They have low insertion loss, excellent ripple, and steeper stop band attenuation. Package provides Pin (thru-hole) and Connector (SMA or N). More frequencies (e.g. 74 MHz, 128 MHz, 385 MHz, 390 MHz, 455 MHz, and 470 MHz) we can support, please Contact us.