The Colorful World Of UHF Band High Pass Filters

According to the International Telecommunication Union (ITU), the UHF or ultra-high frequency band, is the designation for radio frequencies that are in the range between 300 megahertz (MHz) and 3 gigahertz (GHz). What makes the UHF band different from the VHF band, is that UHF radio waves travel via line of sight, hence their path can be blocked by large buildings, hills or mountains, although they can transmit/pass though building walls. UHF frequencies are used for TV broadcasting, cell phone and satellite communication, as well as GPS, Wi-Fi, Bluetooth, cordless phone and other applications. Let’s take a look at how UHF band high pass filters work in this environment.

What Factors Or Conditions Affect UHF Frequency Transmission?

Before we discuss about the main tasks, and abilities, of UHF band high-pass filters, let’s first take a look at the intricacies of UHF frequency transmission. The IEEE, or the Institute of Electronics and Electrical Engineers defines the UHF radar band as having frequencies within 300 MHz and 1 GHZ.

But, the “point-to-point’ transmission and reception of UHF (as well as other frequencies) TV and radio signals is affected by a host of variables, including solar radiation, wind, atmospheric moisture and physical obstructions like buildings, mountains, hills and even trees.

These variables often reduce, or attenuate, the strength of radio signals over long distances, and the effect of attenuation degradation often increases with frequency. UHF TV signals are also more degraded by moisture than lower bands like VHF TV signals.

The Crucial Roles Played By UHF Band High-Pass Filters

Of the different types of electronic filters, RF or radiofrequency filters have an electrical circuit design that is geared to have specific characteristics with respect to the passing, or “attenuation” of frequencies which are applied to it.

There are 3 main types of RF filters – low-pass, high-pass and band-pass filters. High pass filters have a cut-off frequency, of which the higher frequencies have little to nil transmission loss, while signals or frequencies below it have considerable attenuation.

Low pass filters are actually the reverse (or the “antonym” of sorts)  of high pass filters, while a band-pass filter only transmits a selected band of frequencies with considerably no loss, but will attenuate all frequencies that are either higher or lower than the desired band.

High pass filters come in different shapes and sizes, with varying designs and performance levels. Some high pass UHF filters provide more than 60 dB signal rejection of FM and CB band, and are used to block undesired signals below VHF Higher. The filter also passes channels from 7 to 13 and UHF with minimal, or reduced insertion loss.

The main advantages or pluses of UHF transmission is that it has a short wavelength, which is brought about by the high frequency, and the size of transmission and reception antennas is related to the size of the UHF radio wave.

And as UHF band high pass filters vary in construction and purpose, what unifies them is that they’re designed to pass UHF signals from 470 to 800 MHz, and block or refuse entry to VHF, FM and RF signals that overload UHF amplifiers and TV tuners.