You may have seen many examples of the antenna pictured above mounted across suburban roof-tops. This type of antenna is a fairly common UHF TV antenna design which goes under various names such as DB2, 2 bay Bowtie or dual stacked phased array.
Functionally this antenna comprises 2x horizontal wideband dipoles stacked one above the other which are connected together with a low-loss high impedance open wire feed line. The wire screen behind serves as a reflector.
Stacking antenna is a very common method of increasing antenna gain in commercial and amateur radio applications and produces a theoretical 3 dB increase in gain. Remembering that Decibel (Symbol: dB) is a logarithmic unit meaning a 3 dB increase is a doubling of antenna gain.
One of the biggest challenges to providing adequate TV antenna performance is the extremely wide range of frequencies used. For example, international digital television broadcasting UHF Bands IV and V cover a range from 470 - 582 and from 582 - 862 MHz in Europe and up to 960 MHz in the Americas. When you consider a conventional half wave dipole antenna, often colloquially referred to as rabbit ears or bunny ears, has a fractional bandwidth of 8% of it's resonant frequency, this falls far short of the almost 400 Mhz bandwidth required for reliable digital UHF TV reception.
Wideband Antennas
A bowtie antenna is a wire approximation in two dimensions of an ultra-wideband biconical dipole antenna. The bowtie has a fractional bandwidth exceeding 30% and is often used in TV antenna design as it enables strong performance across the entire UHF TV broadcast band.
HD-QUAD: Bringing the power of High-Gain roof-top Phased Array Digital HDTV antenna indoors.
The HD-QUAD A3 is a clear, flexible, window mountable, indoor antenna that is electrically identical to a standard DB2 antenna less the reflector. Manufactued using State-of-the-art printed electronics techniques, it uses highly conductive silver elements which are more conductive than copper and almost twice the conductivity of aluminium elements.
The flexible printed circuit type open wire feed lines are precision designed to correctly phase the incoming signals from the dual stacked antennas while also maximizing antenna efficiency to ensure as much signal as possible makes it to the antenna socket on the back of the TV.
If you need a high-gain UHF digital HDTV antenna without the added expense of roof-top mounting, or you live in an apartment and are unable to mount an external antenna on the building, HD-QUAD may be what you're looking for.
Source: HD-QUAD
