Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.

Terry D.

In message , Terry D
wrote
Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.


With analogue each of the channels are on a different frequency.
Obstructions within the room can affect these frequencies in different
ways. If you have any electronic equipment operating close to the
aerial the interference can swamp the signal you want.

Indoor aerials are not usual regarded as a reliable means of collecting
your TV signals


--
Alan
news2006 {at} amac {dot} f2s {dot} com

On 2007-11-18 19:42:18 +0000, Alan said:

In message , Terry D
wrote
Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.


With analogue each of the channels are on a different frequency.
Obstructions within the room can affect these frequencies in different
ways. If you have any electronic equipment operating close to the
aerial the interference can swamp the signal you want.

For example, interference from dodgy lightbulbs.

In article , Terry D
scribeth thus
Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.

Terry D.



Simple.. Their on different frequencies and chances are that what is
known as multipath is happening this is where some signals take
different paths to get to the aerial and sometimes they cancel out or
add together.


--
Tony Sayer

In article 4740a423@qaanaaq, Andy Hall scribeth
thus
On 2007-11-18 19:42:18 +0000, Alan said:

In message , Terry D
wrote
Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.


With analogue each of the channels are on a different frequency.
Obstructions within the room can affect these frequencies in different
ways. If you have any electronic equipment operating close to the
aerial the interference can swamp the signal you want.

For example, interference from dodgy lightbulbs.



There have been odd instances of fluorescent lighting affecting signals
in the 400 odd MHz area but very unlikely in this instance, more a
problem with multipath with indoor aerials...
--
Tony Sayer

Terry D wrote:
Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.

Terry D.


x-posted to uk.tech.broadcast - Helpful lot. (Except they are about to
prove me wrong on that...) I think you'll get asked where you are.

Andy

Paul Martin wrote:
In article ,
Andy Champ wrote:
Terry D wrote:
Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.

x-posted to uk.tech.broadcast - Helpful lot. (Except they are about to
prove me wrong on that...) I think you'll get asked where you are.

It's caused by standing waves in the reflections from inside the house.

That's one reason why rooftop aerials are always preferred over set top
aerials.

So you get better reflections from trees, power lines and aircraft.. ;-)

On Mon, 19 Nov 2007 00:55:32 +0000, The Natural Philosopher
wrote:

Paul Martin wrote:
In article ,
Andy Champ wrote:
Terry D wrote:
Sorry if this is an inappropriate group for my posting, but I know there are
some very knowledgeable people out there.

I have an 8" LCD Evesham TV (analogue signal), which I watch at my desk
whilst working on my computer. The TV works fine with a small set-top
aerial (normally blu-tacked to the top of one of my printers!). However,
when I want to watch channel 4, I have to move the aerial down by about one
foot so I can achieve decent reception - all other channels are fine. Why
should this be? It doesn't really worry me (except when I want to watch
Countdown) but is there a technical explanation for this? The TV on the
ground floor of my house.

x-posted to uk.tech.broadcast - Helpful lot. (Except they are about to
prove me wrong on that...) I think you'll get asked where you are.

It's caused by standing waves in the reflections from inside the house.

That's one reason why rooftop aerials are always preferred over set top
aerials.

So you get better reflections from trees, power lines and aircraft.. ;-)

Sod's law innit.

DG