Aerial Functions

I vagually understand aerial designs and the necessity for certain
lengths and dipoles etc but we have all seen coat hangers used for car
aerials as well as portable TVs, also roof mounted TV aerials that
have tilted and are no way pointing to the transmitter.

All these situations often still get a decent TV picture.

What I am wondering is, can a satellite dish be used for a normal
analogue TV signal.

I live in NW London and my dish virtually points in the same direction
as Crystal Palace (My TV transmitter), albeit slightly skywards.

Geoff Lane

Geoff Lane wrote:
I vagually understand aerial designs and the necessity for certain
lengths and dipoles etc but we have all seen coat hangers used for car
aerials as well as portable TVs, also roof mounted TV aerials that
have tilted and are no way pointing to the transmitter.

All these situations often still get a decent TV picture.

What I am wondering is, can a satellite dish be used for a normal
analogue TV signal.

I live in NW London and my dish virtually points in the same direction
as Crystal Palace (My TV transmitter), albeit slightly skywards.

Geoff Lane

Isn't life wonderful - especially in the world of antenna design.

No doubt your dish is picking up some UHF signal from Crystal Palace,
but its design and the associated electronic gubbins are probably not
that interested in passing this particular signal through to user the
end of the coax and so what comes out may not be that great.

Mind you, your comment about coat hangers reminds me of a radio skit I
heard some time ago that went something like:

A: "My god, you're pathetic, your clothes are pathetic and even your
car's pathetic - for goodness sake, it even has a coat hanger for a
radio aerial."

B: "Lots of people use coat hangers for aerials!"

A: "Not WOODEN ones, you pillock!"

L3K

On Sun, 19 Dec 2004 13:19:49 +0000, Geoff Lane
wrote:

I vagually understand aerial designs and the necessity for certain
lengths and dipoles etc but we have all seen coat hangers used for car
aerials as well as portable TVs, also roof mounted TV aerials that
have tilted and are no way pointing to the transmitter.

All these situations often still get a decent TV picture.

What I am wondering is, can a satellite dish be used for a normal
analogue TV signal.

I live in NW London and my dish virtually points in the same direction
as Crystal Palace (My TV transmitter), albeit slightly skywards.


Put very simply, the gain of a dish is directly related to its diameter in
terms of wavelengths. At satellite broadcasting frequencies, a standard
60 com dish is many wavelengths wide and has a correspondingly high gain.
AT UHF TV frequencies, it is only about one wavelength wide. If you
fitted it with a suitable feed element, it would work as a perfectly
satisfactory, but very low gain, aerial.

Arthur

I think you'll find that Crystal Palce belongs to Crown Castle not you )

"Geoff Lane" wrote in message
...
I vagually understand aerial designs and the necessity for certain
lengths and dipoles etc but we have all seen coat hangers used for car
aerials as well as portable TVs, also roof mounted TV aerials that
have tilted and are no way pointing to the transmitter.

All these situations often still get a decent TV picture.

What I am wondering is, can a satellite dish be used for a normal
analogue TV signal.

I live in NW London and my dish virtually points in the same direction
as Crystal Palace (My TV transmitter), albeit slightly skywards.

Geoff Lane

On Sun, 19 Dec 2004 13:57:48 +0000, Linker3000
wrote:

What I am wondering is, can a satellite dish be used for a normal
analogue TV signal.

I live in NW London and my dish virtually points in the same direction
as Crystal Palace (My TV transmitter), albeit slightly skywards.

No doubt your dish is picking up some UHF signal from Crystal Palace,

No, I haven't actually tried it due to different connections and I
didn't want to fiddle.

Geoff Lane

On Sun, 19 Dec 2004 13:19:49 +0000, Geoff Lane
wrote:

What I am wondering is, can a satellite dish be used for a normal
analogue TV signal.

They are not very efficient at UHF. That is why Yagi type aerials are
used. They are better at it.

I live in NW London and my dish virtually points in the same direction
as Crystal Palace (My TV transmitter), albeit slightly skywards.

Slightly? Because it is an offset fed dish, it appears to be pointing
somewhat horizontal, but I assure you it is not. Astra 2 is at an
elevation of about 24 degrees in the south.

A: "My god, you're pathetic, your clothes are pathetic and even your
car's pathetic - for goodness sake, it even has a coat hanger for a
radio aerial."

B: "Lots of people use coat hangers for aerials!"

A: "Not WOODEN ones, you pillock!"

Ha-ha!

Very good!


--
MESSAGE ENDS.
John Porcella

On Sun, 19 Dec 2004 18:48:03 -0000, "dylan" wrote:


I live in NW London and my dish virtually points in the same direction
as Crystal Palace (My TV transmitter), albeit slightly skywards.

I think you'll find that Crystal Palce belongs to Crown Castle not you )

Hmm, didn't sound like that when I typed it :-))

Geoff Lane

I think you'll find that Crystal Palce belongs to Crown Castle not you )

Hmm, didn't sound like that when I typed it :-))


Well, he's just being a bit pedantic, ain't he? I mean we all say 'mine' or
'my' when the object is not actually our property. It merely conveys the idea
that the object is the one with which we have some special affiliation or
relationship. For instance, people speak of 'my doctor', 'my teacher', and 'my
council house'.

Bill