VHF-Band Low Pass Filter
Get Quality VHF-Band Low Pass Filter:
VHF band is the frequency band from 30MHz to 300MHz.
Are you designing transmission equipment in the low VHF band? Are you looking for the best low pass filter for the low VHF band? Then you need to get the best VHF Band LC Low Pass Filter. This VHF filter uses LC components in its circuit. Just like the high and low pass filters; it has a “pi” or “T” structure. The inductors and capacitors are used to block frequencies that are above the VHF low cut-off frequency. They allow VHF frequencies below the VHF Cut-off frequency to pass.
A Typical VHF Band Low Pass Filter, ALPF-70M-01
ALPF-70M-01 is a 70MHz Low Pass Filter. It has a 1 dB cut-off frequency at 70MHz and an insertion loss of less than 3 dB at 70 MHz. It is constructed using a 6-pole LC topology and has a rejection of 40dB typically at 100MHz.
| Part Number | 1 dB Cutoff Frequency | Insertion Loss | Rejection | Description |
|---|---|---|---|---|
| ALPF-30M-01 | 30 MHz | 3 dB max | > 50 dB @ 60MHz | 30MHz Low Pass Filter, VHF-Band LC Filter |
| ALPF-50M-01 | 50 MHz | 3 dB max | > 50dB @ 95 MHz | 50MHz Low Pass Filter, VHF-Band LC Filter |
| ALPF-60M-01 | 60 MHz | 3 dB max | > 50 dB @ 110 MHz | 60MHz Low Pass Filter, VHF-Band LC Filter |
| ALPF-70M-01 | 70 MHz | 3 dB max | >50 dB @ 120 MHz | 70MHz Low Pass Filter, VHF-Band LC Filter |
| ALPF-100M-01 | 100 MHz | 3 dB max | >50dB @ 200MHz | 100MHz Low Pass Filter, VHF-Band LC Filter |
| ALPF-144M-01 | 144 MHz | 3 dB max | >50 dB @ 250MHz | 144MHz Low Pass Filter, VHF-Band LC Filter |
| ALPF-300M-01 | 300MHz | 3 dB max | >40 dB @ 500MHz | 300MHz Low Pass Filter, VHF-Band LC Filter |
VHF Band Low Pass Filters: A Short Guide to VHF Waves and Low Pass Filters
Low Pass Filters: The Basics
Low pass filters, or LPFs, can be easily manufactured by connecting in a series a single inductor with a single capacitor. In this filter arrangement, the input signals are tested to the series fusion (with both the capacitor and inductor together); however, output signals are taken across only at the capacitor. Generally speaking, this type of filter is known as a “second-order filter.” Why? It’s called so due to it only having two reactive parts in the circuit, the capacitor and the inductor. In general, the order of a low pass filter is determined by the number of inductors and capacitors that make up the filter.
Very High Frequency: The Basics
In a VHF band low pass filter, the electromagnetic (EM) fields are greatly affected by the planet’s ionosphere and troposphere. The ionospheric multiplication happens usually in the lower part of the VHF wave, mostly frequencies lower than 70MHz.
In this frequency band, the communication coverage can oftentimes expand over the Earth’s surface. The troposphere can cause bending, ducting and scattering, this leads to the wide expansion of communication significantly above the visual horizon.
Low Pass Filters: How it Functions
As the name of the filter implies, a low pass filter is a type of RF filter that permits easy passage of low frequency signals and makes it difficult for high frequency signals to pass through. This filter also provides a much smoother form of a signal, eliminating any short-term fluctuations and leaving the long-term trend.
Very High Frequencies: The Main Uses of this Frequency Band
VHF multiplication traits are ideal for short-distance communication, with a range that’s somewhat farther than line-of-sight from the transmitter. Unlike high frequencies (HF), the ionosphere doesn’t usually show in the VHF band, therefore the transmissions are limited to only the local area (doesn’t interfere with transmissions that ranges from a thousand kilometers away.
VHF is also the least to be affected by atmospheric interference from other electrical equipment than lower frequencies. On the other hand, it’s easily impeded by land features (trees and mountains) than HF and lower frequencies. Plus, VHF is less affected by buildings than UHF (Ultra High Frequencies).
Low Pass Filters and Very High Frequencies: The Applications
The main applications of low pass filters are made evident in audio amplifiers to direct the lower frequency signals to larger bass speakers or to lower any high frequency, also known as the “hiss” type distortion. When it’s utilized in audio applications, this filter is oftentimes referred to as a “high-cut” or a “treble cut” filter.
For the VHF band, the common utilization of these bands include in television and radio broadcasting, two-way land vehicle mobile radio systems (whether it be for private, emergency and military use), long-range communication with radio modems, in amateur radios and in marine communications. Air traffic control communications function at a far distance of 100 kilometers or more to aircraft at a cruising altitude.
Overall Conclusion
The main function of a single VHF band low pass filter, based on the facts stated above, makes communication systems over short-distances a lot clearer and significantly reduces the noise and interference experienced.