On Sun, 9 Nov 2003 21:41:12 -0000, "David Cawkwell"
wrote:

I'm thinking of replacing our rather cheap TV aerial with a new
aerial to improved channel 5 reception and hopefully allow us
to pick up digital TV.

We have two aerials on the roof the top has 10 elements with a small back
plate
and the lower has 10 elements with a larger backplate. Reception of channel
5
on the lower one is pretty good but poor on the higher one.

I notice looking in Maplin that they have several aerials which should get
much better
reception than the aerials I currently have but most don't mention a group.

Also cpc have aerials which quote different groups A,B,C/D,W/B

Questions
1. Will picking a particular aerial group be better or should I simply pick
an
aerial W/B that will? pick up a wide bandwidth.
2. I notice a large difference in the number of elements some having up to
90 elements making
the aerial 2 metres long. Is more elements better?
3. Any advice on make Triax,Antiference,Televes,funke,Maxview

Any advice please. There are simply too many aerials to choose from.


I wouldn#t bother with any of the unbranded junk in the catalogues at
contract grade prices. Triax, Televes and Antiference make good
products and I have examples of product from each in use.

If you want better results on Ch5 analogue and for digital it will
depend on the transmitter that you are using as to whether WB is
required. Generally a grouped antenna will have higher gain and give
greater signal, but this can be compensated by a higher gain WB
antenna and may well prove a better strategy. More elements or the
equivalent of more elements in some designs will improve directional
behaviour as well as gain and signal level.

For best results on digital TV, the antenna should really be aligned
with the use of an error rate tester (either a meter or spectrum
analyser). Digital TV is optimum with lowest error rate in the
derived digital signal, not the signal strength and the two do not
necessarily coincide. For example, reflected signal can spoil error
rate. So it may make more sense to go for a professional
installation.

Also, the antenna should be connected using CT100 satellite cable, not
TV coax. The latter has poor screening and other electrical
characteristics.





..andy

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