Digital
Aerial (Vision 48 element) |
Latest
Prices
|
 |
High
Gain
Quality
Aerial |
| A high gain aerial specially for
weaker signals requiring Digital Terrestrial TV, also suitable as a high
gain Analogue Aerial. |
Features Include
 | 18mm Boom for rigidity |
| Large reflector for high F/B ratio |
| Solid wire elements for low wind load and high strength |
| Large snapshut junction box with supermatch Balun |
|
| What is a Balun?, why is it
important?
A Balun is a small circuit board inside the junction box, it provides
matching between the Aerial and the down lead and reduces noise. |
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Minimising the amount of noise through your
cable is vital with digital terrestrial TV, it is transmitted in data form
(1's and 0's), excess noise will conflict with the data and lead to loss of
channels.
Unlike the analogue signals, all aerials (Except Log periodic) should now contain a Balun,
the down lead should be of CT100 double screened cable and all splitters,
surface plates etc should be screened also. All these steps will reduce
the amount of noise in the system and can be critical if you are
distributing to several TV's. |
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Prior to digital entering the
market, generally speaking a good signal strength indicated a good TV
picture. Now other measurements need to be taken for digital reception.
If you are having your aerial
installed professionally all fitters should now carry the required testing
equipment to provide C/N (Carrier-to-noise ratio), Digital / Analogue
carriers and BER (Bit error ratio)
measurements. This will indicate if a good digital signal is being
received.
Typical Guidelines at
Termination points are:
|
C/N min 26db |
| BER minimum 2E-4 (IE:
2 bits of error in 10,000 bits of data) At PV
BER. |
|
Ask your fitter if the
signals are within these guidelines. |
These
measurements must also be taken in conjunction with the digital carrier
signal and the analogue carrier. This is a minimum requirement and some latitude
should also be considered for the future when signal strengths may
vary. |
|
If all this sounds confusing and
you wish to DIY it, simply
point the above aerial in the direction of the signal, use good quality
double screened cable and ensure that the aerial cable from the TV wall
plate to the receiver is also double screened. See: TV
/ Sat VCR Leads for details on why a good quality fly lead is
necessary. These aerials are designed to give the best possible chance of
receiving Digital Terrestrial TV.
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| Please note that although we supply
a large number of other aerials, the above aerial is boxed and complete
with instructions. All other aerials are bagged and can be damaged
in transit, we would be pleased to supply smaller aerials to personal
callers only. |
Back to: Terrestrial TV
or Information |
