Are sat dishes too small?

On 05/06/2012 8:53 AM, Brian Gaff wrote:
I ask this as some people I know who live here darn souf, seem to always get
duff reception when the cloud cover is bad. OK I don't know enough about the
location etc to comment, but there do seem to be a lot of people in forums
etc complaining recently, and i just wondered if in order to make the dishes
look smaller the gain has been paired to the bare minimum.

Brian



their dishes are the right size - assuming they are pointing in the
correct direction.

--
Gareth.
That fly.... Is your magic wand.

Warm objects in the field of view? I don't know anyone with a greenhouse
hanging in mid air arround here.. grin.

Brian

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!
"David Woolley" wrote in message
...
Brian Gaff wrote:
I ask this as some people I know who live here darn souf, seem to always
get duff reception when the cloud cover is bad. OK I don't know enough
about the location etc to comment, but there do seem to be a lot of
people in forums etc complaining recently, and i just wondered if in
order to make the dishes look smaller the gain has been paired to the
bare minimum.

I think a better question would be: do satellite operators try to get too
many channels into each transponder?

DSB dish sizes tend to be set by planning law. They are set based on what
is permissible without explicit planning permission. (I'm not sure how
this works in Scotland, where you need bigger dishes. It might be they
have larger limits or it might be there is some element of cosmetic sizing
down South.)

The satellite operators are constrained by the power from the photo cells
on the satellites, but choose the technical parameters of their signals so
as to get the maximum revenue (i.e. sell as many channels as possible)
consistent with producing an acceptable signal most of the time.
Increasing the bit rate on a multiplex means a higher signal to noise
ratio is required to receive it accurately.

The system is designed for "most of the time", so heavy cloud may well
break it. Incidentally, they actually increase the uplink power if the
uplink is affected in this way.

I'd suggest that if bigger dishes became common, they would take advantage
of them until the availability was reduced to the current level.

One other variable is that the people with problems may be those with
their dishes least accurately aligned, or maybe even with warm objects in
the field of view.

Brian

Maybe we now get the wrong kind of cloud, or maybe if one looks at the age
of the outdoor kit its either moved or its got issues in some way. The one I
was orignally talking about is about five years old.

Brian

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!
"David Woolley" wrote in message
...
Andy Burns wrote:
David Woolley wrote:

Brian Gaff wrote:

I ask this as some people I know who live here darn souf, seem to
always get duff reception when the cloud cover is bad.

I think a better question would be: do satellite operators try to get
too many channels into each transponder?

squeezing in extra channels would increase artefacts, rather than reduce
signal level or quality.

Obviously once you have chosen the low level coding and aggregate bit
rate, you can only increase the number of channels by reducing the bit
rate per channel. However I'm talking about the process that would have
gone into deciding the coding and bit rate. Whilst there would be a
quality multiplier in determining the actual number of channels, a higher
aggregate bit rate always allows more channels for a given quality, and
they would have chosen the highest bit rate that they could get away with,
subject to available technology and the link budget on the majority of
days.

On Tue, 05 Jun 2012 10:07:55 +0100, Jeff Layman wrote:

On 05/06/2012 08:53, Brian Gaff wrote:
I ask this as some people I know who live here darn souf, seem to always get
duff reception when the cloud cover is bad. OK I don't know enough about the
location etc to comment, but there do seem to be a lot of people in forums
etc complaining recently, and i just wondered if in order to make the dishes
look smaller the gain has been paired to the bare minimum.

Brian


Did you mean to ask "Are Sky dishes too small?"

I have always understood that the 45 cm Sky disk was the minimum size
that Sky could get away with for (usually?) reliable reception. When I
looked into getting Freesat a couple of years - or maybe more - ago, the
minimum size of disk available relatively cheaply, complete with
receiver, was 65 cm. Apart from having to move the dish because of a
tree growing too high, I've never had reception problems from 28.5° here
in Sussex, no matter what the cloud cover.

I went for 65cm, just to be on the safe size.

What is the reception like much further north, particularly in Scotland?

That needs Skye dishes.
--
Peter.
The gods will stay away
whilst religions hold sway

One thing that did intrigue me was that some sats vertical and horizontal
signals are not exactly that and need a bit of skew added, somone here
suggested the dishes were small to make them useless for other sats, but
maybe the skew does that.

Brian

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!
"the dog from that film you saw" wrote in
message ...
On 05/06/2012 8:53 AM, Brian Gaff wrote:
I ask this as some people I know who live here darn souf, seem to always
get
duff reception when the cloud cover is bad. OK I don't know enough about
the
location etc to comment, but there do seem to be a lot of people in
forums
etc complaining recently, and i just wondered if in order to make the
dishes
look smaller the gain has been paired to the bare minimum.

Brian



their dishes are the right size - assuming they are pointing in the
correct direction.

--
Gareth.
That fly.... Is your magic wand.

On Tue, 5 Jun 2012 14:30:18 +0100, PeterC
wrote:

On Tue, 05 Jun 2012 10:07:55 +0100, Jeff Layman wrote:

On 05/06/2012 08:53, Brian Gaff wrote:
I ask this as some people I know who live here darn souf, seem to always get
duff reception when the cloud cover is bad. OK I don't know enough about the
location etc to comment, but there do seem to be a lot of people in forums
etc complaining recently, and i just wondered if in order to make the dishes
look smaller the gain has been paired to the bare minimum.

Brian


Did you mean to ask "Are Sky dishes too small?"

I have always understood that the 45 cm Sky disk was the minimum size
that Sky could get away with for (usually?) reliable reception. When I
looked into getting Freesat a couple of years - or maybe more - ago, the
minimum size of disk available relatively cheaply, complete with
receiver, was 65 cm. Apart from having to move the dish because of a
tree growing too high, I've never had reception problems from 28.5° here
in Sussex, no matter what the cloud cover.

I went for 65cm, just to be on the safe size.

What is the reception like much further north, particularly in Scotland?

That needs Skye dishes.
Oh! ye'll take the high band and
I'll take the low band,
And I'll be in Scotland afore ye.

I'll get ma kilt.
Haste ye back!
I've had ma tea.

--
Graham.
%Profound_observation%

"Brian Gaff" wrote in message
...
I ask this as some people I know who live here darn souf, seem to always
get duff reception when the cloud cover is bad. OK I don't know enough
about the location etc to comment, but there do seem to be a lot of people
in forums etc complaining recently, and i just wondered if in order to make
the dishes look smaller the gain has been paired to the bare minimum.

Brian

60cm works in most of the UK, but at least this is advisable in Scotland.

As most installations are "free" from $ky and any front of house / chimney
stack dishes are limited to 45cm, then this is the size they normally use.
Pretty marginal for coverage especially on poor weather or if water gets in
anywhere.

Brian Gaff wrote:
I ask this as some people I know who live here darn souf, seem to always get
duff reception when the cloud cover is bad. OK I don't know enough about the
location etc to comment, but there do seem to be a lot of people in forums
etc complaining recently, and i just wondered if in order to make the dishes
look smaller the gain has been paired to the bare minimum.

The question is, what is meant by 'too small'? Too small for normal
commercial standards of reliability, yes. Too small if the odd bit of
rain fade can be tolerated now and then, no.

Complaints about poor satellite reception always come down to dish
misalignment, faulty LNB, faulty cable, faulty tuner, terrestrial
interference.

Bill

David Woolley wrote:

DSB dish sizes tend to be set by planning law. They are set based on
what is permissible without explicit planning permission.
The max size set by planning law significantly exceeds the range of
mini-dish sizes.

Bill

Jeff Layman wrote:

I have always understood that the 45 cm Sky disk was the minimum size
that Sky could get away with for (usually?) reliable reception. When I
looked into getting Freesat a couple of years - or maybe more - ago, the
minimum size of disk available relatively cheaply, complete with
receiver, was 65 cm. Apart from having to move the dish because of a
tree growing too high, I've never had reception problems from 28.5° here
in Sussex, no matter what the cloud cover.

We find it helpful to use larger dish sizes for communal systems where
there is a lot of amplification, because the increased s/n ratio (less
beamwidth means less sky noise) means the amps aren't having to carry
the whole bandful of noise at a high level. Also, really clean muxes can
stand more amplifier noise.

Bill