mm wrote:
On Wed, 02 Dec 2009 23:46:06 +0100, Sjouke Burry
wrote:

mm wrote:
On Wed, 02 Dec 2009 20:26:45 +0100, Sjouke Burry
wrote:

mm wrote:
On Tue, 1 Dec 2009 14:35:23 -0800 (PST), whit3rd
wrote:

On Nov 30, 11:46 pm, mm wrote:
One more antenna question: Antenna pitch?

That is, my attic has a pitched roof and the antenna for channels 7 to
60 that I'm thinking of now is almost 13 feet long.
Yes, it matters; the main part of that long antenna is 'director'
elements, which create a kind of shadow on the active
dipole. The rays get past if you aren't roughly lined up with
the line-of-sight to the transmitter.

Also, such a long antenna has high 'gain' which means it
MUST be aimed carefully; how can you possibly adjust it
if it's bumping into the roof?
I may be confused about what "gain" is. Why would a high gain antenna
have to be aimed carefully? If it has high gain, it seems like it
would have some gain to spare if it were badly aimed.

If it had low gain, it seems like it would have to be aimed precisely.

High gain means "narrow bundle" , so a high gain antenna needs
careful aiming.
So what aobut people on mountains and in valleys, where the
transmitter is lower or higher than they are. Should their antennas
be tipped down or up to aim at the transimitting antenna?

I never hear anyone recommend that, and afaicr (and I don't spend much
time near mountains, but some), every outdoor antenna I've ever seen
has been horizontal.
It turns a little bit into nit picking, but Yes try to aim
as accurately as possible at the transmitter, especially with
multi-element antennas.
And keep in mind,that an antenna cannot look through a big hill
or a mountain. And only with some difficulty through your house/roof
or that of the neighbour.
For the hill/mountain, you might need a repeater on that hill/mountain top.
Or try to find a reliable reflection around those obstacles.
In my country the digital tv is polarized vertically, so although we
can use the same old antennas, they have to be turned on their sides,
and vertical aim is even more important.

Very interesting. Really

What about places where there is line of sight between the
transmitting antenna and the home antenna, but the home is a lot lower
or higher than than the T-antenna. Does the home antenna need to be
tipped up to point to a transmitting antenna that's higher? It sounds
like that follows from what was said ealier in this thread, but I've
never seeen it done or recommended.
Well, you aim carefully at the horizon, and hope that enough radiation
is following the earth surface.
Some bending down always occurs, and hopefully for you it is enough.