In article , UnsteadyKen
scribeth thus

tony sayer wrote...

Think how much better it would be with a decent Vertical dipole;-)..

Who knows why they use these halos?,

Simple, easy to mount, and above all they get them cheap...

I think some aerial "riggers" don't have that much idea of what the do
or are doing other than "we wire this up and it usually works"

DAB is a V dipole, it is the
standard council communal installation round here for sheltered housing
and flats, consisting of a large sat dish, FM halo, DAB dipole and two
TV aerials; one pointing north for Waltham and one south for Sandy
Heath all mounted on a sturdy pole.

Receiving two different TV regions with equally strong signals confuses
a great many Freeview boxes and TV sets, plus their elderly owners.

Equipment which detects this and allows you to choose a region cope
fine, but lots end up with the whole 70 channels duplicated in the
800's

Why are they doing that? ITV 1 is much the same anywhere in that area
apart from the news I'd have thought Waltham is more your backyard
rather than the outpourings of Narwich....

In fact we did some tests on one of they and they did do better than a
coat-hanger .. which incidentally wasn't resonant;-!..

It gets those results through the use of massive amplification, whole
swathes of the VHF band are obliterated by the resulting harmonics from
the local main transmitters, (Peterborough and Geddington)



Ah!, I'm sure Bill Wright, not on this ng, could give you chapter and
verse of what they find wrong when asked in to sort these "systems"....

--
Tony Sayer