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FILTER SOLUTION EXPERT
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Customized RF Components and Microwave

2019-11-15

In the VHF and UHF radio spectrum allocated a group of frequencies to radio communication in civil and military aviation that also referred as Aircraft band or Airband. Frequency band assignment by FCC and FAA is from 108 to 137 MHz for civil aircraft communications; from 225 to 400 MHz for military aviations. Within the aircraft band is mostly used for navigational by radio aids and air traffic control.

Navigational by radio aids (for aviation) is navigation information derives from ground radio beacons such as VOR (Very high frequency Omni-directional Range), DME (Distance Measuring Equipment) and NDB (Non Directional Beacon), ILS (Instrument Landing System) aviation equipments or broadcast stations. It can provide services as distance measurement between the communication station and the aircraft’s position, time signals, assist pilots landing in low visibility conditions, medical advice, stations broadcasting navigational warnings etc.

Air traffic control (ATC) is a service provided by ground-based personnel who in the air traffic control center on the monitoring of air traffic in a controlled airspace, specifically tower control, approach and departure control, and route control. They also can provide advisory services to aircraft in non-controlled airspace.

In aircraft communication radio, the reception of radio signals are usually disrupted by non-RTF (Radio Telephony) frequency users where come from commercial stations on the ground, and affected by weather and atmospheric conditions. A typical situation as following:

Several airports, hundred nautical miles apart, are shared the same frequency. In the static generated by thunderstorm clouds or in high pressure, radio transmission station using the same frequency as authorized aeronautical transmitter be jamming even it is beyond the protected range, e.g. result in aircraft landing to one airport having interference from the ATC. The air traffic control center personnel on the ground perhaps not aware the landing aircraft is suffering radio interference because he may unable to hear the transmissions relating to the other airport.

Some interference is from unauthorized or malicious transmissions. Under rare occasions when unauthorized stations have made malicious transmissions on the same frequency, probably intention of misleading pilots at critical stages e.g. phases of flight (takeoff and landing) where false messages.

To consider RF Filter design into the wiring for the radio's, transponders, and GPS would be an efficient method to eliminate inside and outside interference of aircraft communications coverage.

Engineering team of TEMWELL specialty RF Bandpass Filter design in VHF and UHF can support standard and custom frequency in different bandwidth for aircraft band. The following is demo part number table. Featured specs are very low insertion loss, flat in passband as ripple less than 1.0dB, stop band attenuation steeper can upon user requirement. Package supports Pin (thru-hole) and Connector (SMA female or N female).

proimages/application/Aircraft_Filter/Aircraft_CommunicationBPF-2.jpg

Demo center frequencies are different, but have various bandwidth options. Each demo center frequency accepts to specify new one within a particular range. We can re-design the filter accordingly to your wanted new center frequency in the same bandwidth and the same other specs.

In table A has various bandwidth options are 5 MHz, 10 MHz, 20 MHz and 30 MHz. Each demo center frequency can accept re-design range from 126 to 145 MHz, e.g. TT6755D1 demo at 140 MHz, but can be specified at 128 MHz.


 

A. Frequency: 144MHz Spec (Freq / BW / IL) Size (LxWxH) Accepted Type
TT6755D1-144M 144MHz / 5MHz / 3.5 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67677B1-144M 144MHz / 10MHz / 3.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67381B-144M 144MHz / 20MHz / 3.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT63218B1-144M 144MHz / 30MHz / 1.5 dB TT (22.8x7.6x12.5) Pin Type / Module Type
B. Frequency: 430MHz Spec (Freq / BW / IL) Size (LxWxH)  Accepted Type
TT67462B-430M 430MHz / 7MHz / 5.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67477B-430M 430MHz / 11MHz / 3.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67157B-430M 430MHz / 15MHz / 3.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT6778B-430M 430MHz / 21MHz / 3.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67295B-430M 430MHz / 34MHz / 3.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67256B-430M 430MHz / 40MHz / 2.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67409B1-430M 430MHz / 60MHz / 2.0 dB TT (22.8x7.6x12.5) Pin Type / Module Type
TT67870B-430M 430MHz / 100MHz / 1.5 dB TT (22.8x7.6x12.5) Pin Type / Module Type


Our Bandpass filter quality is reliable, please refer to Shock Test Report and Vibration Test Report. Also, you can click to check Temperature Test and Other qualification certificated. Perhaps you are interested in more types of RF filter (Notch, Lowpass, Highpass), higher power filter (200 Watt above), higher frequencies filter (up to 60 GHz), or Duplexer, Isolator, Coupler, Splitter and Combiner that we can offer, please refer Product or Contact us

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