Correct pointing direction of TV Aerial viewed from the garden

[john west]

I have got from an internet page the exact bearing in degrees to which
to point my Aerial straight at the Freeview Televsion Transmitter
Station. I've downloaded a compass app to my android phone, so i know
north and south etc.

The aerial is up on the wall at first floor height. I can reach the
aerial to change its direction from an open bedroom window.

Is there any way i can *exactly* point the aerial to the recommended
bearing, by sighting it from the rear garden? Since i cannot lay the
phone on the aerial and read the phone at the same time.

Thanks.

[michael adams]

"john west" <mail.in...@mail.invalid> wrote in message
news:mql1rd$79m$1...@dont-email.me...

Tie one end of a ball of string to the base of the aerial. Throw the ball of
string down into the garden. Go down into the garden and assuming you
have a lawn hold the other end and walk around until the string is at the
correct bearing. Drive a stake into the lawn and tie the string to that.
Go upstairs and adjust the aerial until its parallel to the string.
In the absence of a lawn attach the string to the fence, object, trees etc
in the garden at the correct bearing.


michael adams

...

[michael adams]

"michael adams" <mjad...@ukonline.co.k> wrote in message
news:mql2bn$917$1...@dont-email.me...

Not "parallel". Just at the same bearing as the string

>
>
>
>

[Caecilius]

You don't need to *exactly* point the aerial at the transmitter.

What I did was to look for a landmark that was at approximately the
correct bearing, and point the aerial at that. In my case it was a
bridge, but it could be a tree, hill etc.

Then see if you've got a stable picture. If you have, then that's all
you really need. IME with digital TV, good enough is good enough:
providing there's no drop outs or artifacts you don't gain anything by
improving signal strength or quality.

But if you're like me you'll want to get the best signal, so see if
your TV has a built in signal strength and quality meter. Mine had,
so I spent half an hour getting that about as good as I could. But
really it made no difference to the picture quality.

[alan_m]

Print out a satellite image from Google maps of your local area. Draw a
line from your aerial position towards the transmitter (using the
bearing information) See which local landmark, say, half a mile away,
the line passes through. When you adjust the aerial point it towards
your chosen landmark. Use a phone camera to look down the centre boom of
the aeril to see if it is pointing at the landmark.


As others have said, some localities require the aerial to be pointed
'off bearing' to avoid obstructions in the direct transmitter path.
Often just checking where all your neighbours aerials are pointing can
give you an idea. However, around my way aerials seem to be pointed
towards one of four transmitters. The local aerial installers don't seem
to realise that there is almost a clear line of site to Bluebell Hill
and attempt to put in large aerials to get Crystal Palace which is
blocked by nearby town centre tower blocks.

--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

[198kHz]

On 14/08/2015 16:36, john west wrote:

Earlier replies have given some good advice obviating the need for a
compass.

If you do use the compass app, do test it out first, as they are not
renowned for accuracy without some faffing about involving 'figure of
eight' gyrations of the phone. Even then, you're probably screwed if the
phone is in a case using magnets for the sleep/wake function.

--
198kHz

[The Natural Philosopher]

Of course. Drop a plumb line from as near the aerial as you can, and
where it hits the garden, pout your phone down and see where its
pointing. Then pick some object in the garden that is along that
bearing, or indeed depending on where you are any salient object outside
your garden along that line. The further away the better.

Then point the aerial at that object.

Remember the beam width on all but the most enormous aerial will be
quite broad - 5-10 degrees out wont make a huge difference. In my case
what was more important was to align a null towards the OTHER
transmitter I could sometimes get signals from that I didn't want.


> Thanks.


--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

[tony sayer]

In article <077ssa50se86mldo2...@4ax.com>, Caecilius
<nos...@spamless.invalid> scribeth thus

>On Fri, 14 Aug 2015 16:36:54 +0100, john west
><mail.in...@mail.invalid> wrote:
>
>>I have got from an internet page the exact bearing in degrees to which
>>to point my Aerial straight at the Freeview Televsion Transmitter
>>Station. I've downloaded a compass app to my android phone, so i know
>>north and south etc.
>>
>>The aerial is up on the wall at first floor height. I can reach the
>>aerial to change its direction from an open bedroom window.
>>
>>Is there any way i can *exactly* point the aerial to the recommended
>>bearing, by sighting it from the rear garden? Since i cannot lay the
>>phone on the aerial and read the phone at the same time.
>

Download Google earth then on that you can draw a line between you and
the TX concerned and you can then scroll it right back to where you live
and then see where the aerial needs to be pointed by reference to
something in your garden or a nearby house etc.

Most TV aerials aren't that sensitive to directional errors of a few
degrees. Height is far more important...
--
Tony Sayer

[David]

On Fri, 14 Aug 2015 17:10:38 +0100, Chris Hogg wrote:

> On Fri, 14 Aug 2015 16:36:54 +0100, john west
> <mail.in...@mail.invalid> wrote:
>

> IME pointing the aerial directly at the transmitter doesn't necessarily
> give you the best signal. There is a significant hill between us and the
> transmitter that obstructs line-of-sight reception,
> and nearly all the aerials on this side of the hill point to one side of
> the hill. I presume some sort of diffraction takes place. Also, aerials
> are never so sensitive that they need precise alignment. A degree or two
> either side makes not a lot of difference. The best way to align the
> aerial is to use a signal strength meter, but unfortunately good ones
> are only afforded by professionals. The alternative is to check the
> strength/quality values using the TV itself, moving the aerial a little
> and re-checking, until you get the best result.

On the subject of signal strength meters.

http://www.amazon.co.uk/Fringe-Electronics-Pro-Satellite-Finder/dp/
B00LGWN87S

Just over £20 on Amazon - may be cheaper elsewhere.

I have one (IIRC a certain Bill Wright mentioned it) and it worked very
well for aligning an external TV aerial. I have a "swinging needle" meter
for aligning the satellite dish, so I don't remember trying this (although
it was a while back).

We now use it in the camper for aligning the TV aerial at each new site -
and it is quick and effective.

It should be sensitive enough to align your aerial.

Cheers

Dave R


--
Windows 8.1 on PCSpecialist box

[John Rumm]

Few aerials are directional enough to make it that critical. You would
be better off aligning it using the signal strength / quality readout
from a TV decoder.


--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

[tony sayer]

In article <d372p1...@mid.individual.net>, alan_m
<ju...@admac.myzen.co.uk> scribeth thus

>On 14/08/2015 16:36, john west wrote:
>> I have got from an internet page the exact bearing in degrees to which
>> to point my Aerial straight at the Freeview Televsion Transmitter
>> Station. I've downloaded a compass app to my android phone, so i know
>> north and south etc.
>>
>> The aerial is up on the wall at first floor height. I can reach the
>> aerial to change its direction from an open bedroom window.
>>
>> Is there any way i can *exactly* point the aerial to the recommended
>> bearing, by sighting it from the rear garden? Since i cannot lay the
>> phone on the aerial and read the phone at the same time.
>>
>> Thanks.
>
>
>Print out a satellite image from Google maps of your local area. Draw a
>line from your aerial position towards the transmitter (using the
>bearing information) See which local landmark, say, half a mile away,
>the line passes through. When you adjust the aerial point it towards
>your chosen landmark. Use a phone camera to look down the centre boom of
>the aeril to see if it is pointing at the landmark.
>
>
>As others have said, some localities require the aerial to be pointed
>'off bearing' to avoid obstructions in the direct transmitter path.
>Often just checking where all your neighbours aerials are pointing can
>give you an idea.

As long as it hasn't been a stream of cowboy riggers following each
other blindly;!..

>However, around my way aerials seem to be pointed
>towards one of four transmitters. The local aerial installers don't seem
>to realise that there is almost a clear line of site to Bluebell Hill
>and attempt to put in large aerials to get Crystal Palace which is
>blocked by nearby town centre tower blocks.
>

That usually happens over a long time period like round this way when it
was Crystal place then Belmont followed by Sudbury then the mighty sandy
heath opened up and most all bits of misplaced metalwork in the sky sort
of worked a bit better..

But even then the channel 5 Cambridge relay came and has now gone still
a few random aerials on that!..
--
Tony Sayer

[Terry Casey]

In article <OKSdnZSKFNO0yFLI...@brightview.co.uk>,
see.my.s...@nowhere.null says...

>
> On 14/08/2015 16:36, john west wrote:
> > I have got from an internet page the exact bearing in degrees to which
> > to point my Aerial straight at the Freeview Televsion Transmitter
> > Station. I've downloaded a compass app to my android phone, so i know
> > north and south etc.
> >
> > The aerial is up on the wall at first floor height. I can reach the
> > aerial to change its direction from an open bedroom window.
> >
> > Is there any way i can *exactly* point the aerial to the recommended
> > bearing, by sighting it from the rear garden? Since i cannot lay the
> > phone on the aerial and read the phone at the same time.
>
> Few aerials are directional enough to make it that critical. You would
> be better off aligning it using the signal strength / quality readout
> from a TV decoder.

If you have any visible landmarks - including houses - which are visible from
your window, see here:

http://www.macfh.co.uk/JavaJive/AudioVisualTV/TerrestrialTV/TerrestrialCalcul
ator.php

or, if it wraps,

http://tinyurl.com/32txwbo

Enter your post code and transmitter (from the drop down lists) to calculate
the details.

Now scroll down to the bottom and select OS Map

Scroll the map so that the green place marker is in the centre, then expand
the scale fully.

The marker will be add the post code centre, so grab the marker and drag it
so that the green line passes through the precise position of your aerial.

You can now see where the line passes the other landmarks.

--

Terry

[michael adams]

"tony sayer" <to...@bancom.co.uk> wrote in message news:Gtz06ZPy...@bancom.co.uk...

> In article <077ssa50se86mldo2...@4ax.com>, Caecilius
> <nos...@spamless.invalid> scribeth thus
>>On Fri, 14 Aug 2015 16:36:54 +0100, john west
>><mail.in...@mail.invalid> wrote:
>>
>>>I have got from an internet page the exact bearing in degrees to which
>>>to point my Aerial straight at the Freeview Televsion Transmitter
>>>Station. I've downloaded a compass app to my android phone, so i know
>>>north and south etc.
>>>
>>>The aerial is up on the wall at first floor height. I can reach the
>>>aerial to change its direction from an open bedroom window.
>>>
>>>Is there any way i can *exactly* point the aerial to the recommended
>>>bearing, by sighting it from the rear garden? Since i cannot lay the
>>>phone on the aerial and read the phone at the same time.
>>
>
> Download Google earth then on that you can draw a line between you and
> the TX concerned and you can then scroll it right back to where you live
> and then see where the aerial needs to be pointed by reference to
> something in your garden or a nearby house etc.

The aerial is on the wall beside the window. The Op can't stand behind
the aerial to point it at anything. Hence my suggestion of lining
it up with a piece of string. Providing he can reach out maybe using
a cane and can loop string around the base of the aerial there should
be no problem. Whether he actually needs to point to the exact bearing
or not is an entirely different question. And not the one he asked.


michael adams

...

[Muddymike]

What's wrong with the Simpsons method?

Homer tweaks the direction of the aerial whilst Marge watches the TV and
shouts when best picture is seen. No need to lie on the ridge like Homer in
this case!

Mike

[Bill Wright]

Caecilius wrote:
>
> Then see if you've got a stable picture. If you have, then that's all
> you really need. IME with digital TV, good enough is good enough:
> providing there's no drop outs or artifacts you don't gain anything by
> improving signal strength or quality.

There are often problems if an aerial is mis-aligned, even if it is
receiving a strong-enough signal.
1. There might be no 'margin of error' so if the signal strength drops
reception might be affected.
2. The directional characteristics of the aerial are defeated, so
anything coming from the direction the aerial is looking has a gain
advantage over the wanted signal. This could be CCI or other interference.
3. For the same reason even interference from other random directions is
more likely to have an effect.
4. Pick-up of reflected signals is more likely to have a visible effect.

Bill

[John Rumm]

Yup JavaJive's site is rather nifty, and I have used it for getting sat
dishes pointing in about the right direction in the past.

However having spent many hours sat on roof tops with my trusty DTV
signal meter[1], I have found that even supposedly highly directional
aerials are not *that* directional. You will certainly be able to find a
sweet spot, as you rotate and check the levels. But its surprising that
even being (say) 10 degrees off either direction is not normally that
noticeable.


[1] Swires "Terry"