Are sat dishes too small?

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

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!

"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.


The belt and braces wearers amongst us install the next size up just in
case.
No idea of any recent problems though - wasn't watching it yesterday.

--
No plan survives contact with the enemy.
[Not even bunny]

Helmuth von Moltke the Elder

(\__/)
(='.'=)
(")_(")

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

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.

DSB dish sizes tend to be set by planning law. They are set based on
what is permissible without explicit planning permission.

Sky zone1 elliptical dishes are considerably smaller than the 1m dishes
usually allowed without planning permission.

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.

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

--

Jeff

In article , Jeff Layman
scribeth thus
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.

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


ISTR that Sky kept the size of the dish small so as to prevent them
being used for any competing satellite service. Don't know if thats
strictly true;!.

Course a lot of them are poorly aligned and they have low "ish" gain
anyway so no surprise when they fall over in bad weather;!...


--
Tony Sayer

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.

Brian



Or is it just poor installation?

I have fitted a zone 2 mini-dish in an area where 99.9% of installations
are a zone 1 dish.

Previously I had a zone 1 dish and the only time I lost signal was when
it was raining so hard the road outside my house became a 6 inch deep
river for a short period.
--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

"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

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!


Most people who, like myself, spend much of their time living on a canal
boat use a 12" dish because it's beam width is slightly greater and so the
signal doesn't keep being interrupted when the boat moves slightly. There
isn't ever a problem with signal strength (unless we're moored behind a
tree!)

--
Allan Jones - N/B 'Keeping Up'
www.keeping-up.co.uk

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.

David Woolley wrote:

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.

True. Does the symbol rate, QAM and FEC setting vary purely based on
which satellite and beam a transponder is on, or based on more
commercial considerations? I presume Astra/Eutelsat set the parameters
unless someone is renting an entire transponder?