BPF For VHF UHF Transmitter & Receiver

RF Filter for Radio/Telecommunication Transmitter & Receiver to omit interference

RF systems operate at Radio Frequency, range varies between 30 kHz and 300 GHz. In particular, the VHF (very high frequency) 30 MHz to 300 MHz and UHF (ultra high frequency) 300 MHz to 3000 MHz frequency ranges are the most widely used in FM, television broadcasts, land mobile, maritime mobile communications, ground-to-air, air-to-air communications, two-way radios, satellite radio, weather radio, remote control system and amateur radio.

In Terrestrial, Marine and Air communication networks and related RF modules the transmitters and receivers are indispensable. RF transmitter receives serial data and transmits it wirelessly through its antennas connected. And then transmitted data is received by RF receiver which is operating at the same frequency as like the transmitter.

Interference is at least an occasional problem with most types of radio and wireless devices. The effects of interference range from being a minor annoyance to making the wireless system completely unusable. Two types of interference are common occurred in radio and telecommunication transmitter and receiver: Radio Frequency Interference (RFI), and Intermodulation interference.

★RFI is caused by radio and TV transmitters, communications equipments, and other types of device that generate radio frequency power when they're operation. As like direct interference when occurs there is another strong radio signal on the frequency used by the wireless system. E.g. TV transmitter are very powerful and can affect radio communication systems at distances of 100 miles (160 km) or more. When interference happend, the first step should be to confirm whether the radio communication systems working frequency is on local TV channel in use in the area. It is a serious problem that must be corrected in order for the radio communication systems to be fully usable.

★Intermodulation interference is caused by in the wireless receivers by the combination of two or more strong radio interfering signals. The interfering signals mix together in the wireless receiver to generate an internal signal which is close to the frequency of the receiver; also it caused by the signals either from other wireless transmitter combines with a strong local TV signals. Such internally-generated signals would interfere on another wireless system normal operation. General resolving intermod problems requires that one of the frequencies involved to be changed. However it is quite complicated and time wasted on the entire design concept.