Television technology has come a long way and, with most countries going totally digital, the old analogue television broadcast is on the way. Different countries have adopted one or several digital television broadcast standards that include DVB, ATSC, ISDB, DTMB, and DMB. These digital signals may be delivered by satellite, cable, or telecommunications, as well as the cost-free over-the-air signals, and users can select any according to their budget and requirements. As the efficiency of digital technology is significantly higher than that of analogue technology, doing away with analogue broadcasting frees a part of the scarce radio spectrum, which can then be allocated for other uses. Other benefits include giving high-quality picture and sound and low operational costs.
For terrestrial implementation of DTV technology, the digital signals broadcast by transmission towers are picked up by the consumer’s television aerial. Freeview is UK’s terrestrial DTV. Freeview service providers offer numerous free-to-air digital TV channels, paid channels, radio stations, and other services that consumers can get using a TV aerial, provided the consumer is within the Freeview coverage area. Consumers with older TV sets must use an analogue-to-digital converter box to receive digital broadcast, whereas newer TV sets are designed with built-in receivers to pick up digital signals, and a Freeview aerial is the only requirement. Sometimes an aerial upgrade might be necessary; additionally, one can reuse existing loft aerials and set-top aerials if they are in a good condition.
In order to sort through this often consuming jumble of technological information, consumers must familiarise themselves with the topic before making a purchase. Various options are available with regard to using aerials to receive digital broadcasts, and the suitable choice is based upon one’s needs and budget. Should one decide that a Freeview aerial is needed, he or she will a variety of them readily available at online sites such as eBay.
Television Aerials Explained
The images and sounds during a shoot captured by the television cameras and sound equipments such as the microphones are converted into electrical energy. These energy signals are amplified and pass through massive, very tall metal towers called transmitters. The resultant powerful electric signals vibrate along the antenna towers to create invisible electromagnetic radio waves that are propagated at the speed of light. These radio waves from the television transmission towers are picked up by aerials installed atop homes and buildings.
However, tall structures such as chimneys, buildings, and hills in the vicinity can obstruct these signals. When the radio waves hit the metal it causes the electrons in the aerial to vibrate thereby creating a weak electric signal. These signals are then decoded by the converter box and systems within the TV to be converted into audio and video that displays on the TV screen. Aerials are therefore an important medium for receiving television programmes, uninterrupted and with great clarity.
Attributes of the Aerial that Contribute to Good Digital Signal Reception
As noted above, the electrons of the aerial or antenna vibrate when hit by radio waves. This is ‘resonance’, and varying frequencies of radio waves resonate differently as they hit the aerial, with one frequency causing optimum resonance to give the perfect picture and sound quality. The best design type of resonant aerial to handle the available frequency band must be considered, as a high-gain aerial provides focussed and increased signal strength.
Another factor that enhances aerial performance is the physical location of the aerial. The most suitable location for the TV aerial is mounted outdoors at the highest level possible, where it directs the aerial towards the transmitter. Proper installation of the aerial also ensures smooth transfer of signals for clear images without pixelation or freezing.
Various Types of Freeview Aerials
Knowing the range and quality of the signal strength available in one’s area of residence is crucial in determining whether one’s existing aerial is sufficient, or whether one needs an upgrade or even if only an entirely new aerial will do. DTV uses both VHF and UHF frequencies; in the case of terrestrial digital TV broadcast, UHF aerials are ideal as most channel allocations are in the UHF frequency band. An aerial that can receive signals from all stations to give both VHF and UHF should be one’s first choice.
This is a unidirectional aerial used when the frequency is over 10 MHz. It has several elements connected by the longest element, the boom. The rear element is the reflector and the one preceding it is the driven element, while the rest of the elements of the Yagi aerial are called directors.
To increase the bandwidth in this simple antenna, corner reflector assemblies can be added to the Yagi aerial. These boost performance of the lower channels while maintaining the higher ones, increasing the gain of antenna over the whole UHF band.
Freeview Outdoor Aerials
Several types of outdoor aerials are available, which vary amongst themselves in cost as well as in efficacy and features. Some basic designs include the dipole aerials. This is the simplest outdoor aerial, and its design may be folded, bow-tie, or loop style. Amongst these, the bow-tie variation gives a wider bandwidth.
Reflector aerials are common. These have a large conducting plane that reflect the radio waves that fall on them and focus signals onto a single dipole. The paraboloid dish is one such aerial, but a much larger one with a much higher gain.
Long-periodic dipole arrays, or LPDA, are antennas that have several dipoles arranged on a criss-crossed front. Mostly for VHF TV, LPDA designs are available as the straight LPDA and the Vee type LPDA.
Indoor TV Aerials
In general, one is unlikely to receive a good digital signal reception using an indoor TV aerial, as walls, doors, furniture, and other impediments inhibit performance. However, in places where the signals are strong or proximity to the transmitter with a clear path is possible, one may achieve robust digital services using indoor aerials. Another alternative may be to upgrade the gadget or use a dedicated rooftop aerial to tune the digital box, because the box stores the channels once it is tuned. The indoor aerial will find it easier to pick up signals after this. The rabbit-ears dipole aerial is one indoor aerial that picks signals in the UHF bandwidth.
Ways to Improve Signal Reception
If there is a hitch in receiving digital signals, there are a number of things one may look into, before going in for replacement or repairs, which can greatly improve signal quality and strength.
Raising the height of the aerial or changing its location away from any impediments in the vicinity will allow better reception and picture quality.
Aerial with Higher Gains
Changing the old aerial to another with a higher gain on the available channels that receive poor signals will help to improve those channels. Upgrading the old aerials with preamplifiers can also improve their ability to capture signals.
Check Cables and Connectors
Using high-quality, quad-shielded coaxial cables and TV aerial fly leads can reduce interferences and disturbances, when signals from other home appliances intercept TV signals.
How to Buy Freeview Aerials on eBay
Superior-quality TV aerials of various types are available on eBay at highly competitive prices. Shoppers looking to buy aerials for Freeview and such other DTV services will find several pages with listings of aerials after typing the keywords ‘Freeview aerial’ in the search bar. Shoppers can then select their products and purchase them from top-rated sellers, who have been awarded the yellow Top Sellers badge in recognition of their quality service and high percentage of positive feedback from satisfied customers.
Most sellers provide relevant details about the products as well as a couple of images with the zoom function so that shoppers can thoroughly inspect the product. eBay encourages shoppers to correspond with the seller about any queries or doubts they may have about the product before committing to buy. Additionally, one can check out the seller’s information, which this available along with contact information is provided on the individual listing page. Once fully satisfied about the product, the shopper can go on to make the payments using one of the numerous secure options provided by eBay.
Watching one’s favourite television channel is a great way to relax after a hard day’s work, and watching the characters come alive, vibrant, and clear enhances the pleasure. This experience is now possible with digital television signals that broadcast the sharpest and clearest images and are captured vividly by the right aerial. One must have an aerial that can capture both VHF and UHF signals, as well as the converter box and a TV with built-in digital tuner, as prerequisites for receiving DTV. Several types of indoor and outdoor aerials are available, but the best choice to receive strong signals is an outdoor aerials. Some of the types of aerials available are Yagi aerials, dipole aerials, and the variations in design of dipole aerials such as bow-tie, loop, folded, and the indoor rabbit-ears dipole aerials. Shoppers should select aerials with high gain in order to receive channels in a wide frequency range. Additionally, aerials can also be upgraded with preamplifiers to increase their capacity to capture signals from a greater bandwidth.
One should choose the location of the outdoor aerial judiciously, situating it at a vantage height with no obstacles as the aerial points in the direction of the transmitter. Finally, fitting and cables of high quality ensure that the performance is not compromised.