On Fri, 4 Jan 2019 20:38:59 +0000, Bill Wright, another mentally challenged,
troll-feeding, senile idiot, blathered:


How long are the cables, and what sort of cable?

Bill

Shut your gob, troll-feeding senile Usenet scum!

On Fri, 4 Jan 2019 20:49:37 +0000, Bill Wright, another mentally challenged,
troll-feeding, senile idiot, blathered:


Why not? If you're close enough the signal levels can easily be excessive.

Bill

So for how long are you two prize idiots going to go on about that ****
again? tsk

Commander Kinsey wrote:
On Fri, 04 Jan 2019 02:35:47 -0000, Bill Wright wrote:

On 03/01/2019 21:18, Commander Kinsey wrote:

Anything the cable can pick up the aerial can pick up. But the aerial is
designed to pick up and the cable is designed to not pick up so the
aerial will pick up more. Sit on a roof in a city with an analyser and
an aerial and you'd be surprised at the noise floor.

Shouldn't any noise be at a different frequency, so ignored by the
receiver in the TV?

Noise can be at any frequency. Usually when there's a noisy background
(if that's what I can call it) that could well emanate from a
multiplicity of sources the noise power will be wideband. It won't
necessarily be equal across any given frequency band, but it will
normally be continuous across the band. This means that some of it will
be within the bandwidth of the signal we are attempting to receive and
decode. If we are very unlucky it will peak within the bandwidth of the
signal.

A very small part of the noise floor is 'cosmic noise', about which we
can do nothing.

Normally the biggest source of noise in a receiving system is the first
active device the signal encounters in the system.

Remember that the level of the noise and the level of the signal aren't
important; it's the ratio between the two that matters. Once that ratio
is set no amount of amplification will improve reception.

But if the noise is generated inside the TV receiver, or in the wire from
aerial to TV, and you amplify the signal before that point, you improve the ratio?

I'm glad that since digital was invented I've stuck mainly to dishes.
Way less problems when you're only picking up from one very specific
direction.

Yes, I've always thought satellite was much easier than terrestrial.

Must cost a lot to put those things up there though.

Pretty Astranomical .


Ill get my coat.

GH

On Fri, 04 Jan 2019 23:18:08 -0000, Marland wrote:

Commander Kinsey wrote:
On Fri, 04 Jan 2019 02:35:47 -0000, Bill Wright wrote:

On 03/01/2019 21:18, Commander Kinsey wrote:

Anything the cable can pick up the aerial can pick up. But the aerial is
designed to pick up and the cable is designed to not pick up so the
aerial will pick up more. Sit on a roof in a city with an analyser and
an aerial and you'd be surprised at the noise floor.

Shouldn't any noise be at a different frequency, so ignored by the
receiver in the TV?

Noise can be at any frequency. Usually when there's a noisy background
(if that's what I can call it) that could well emanate from a
multiplicity of sources the noise power will be wideband. It won't
necessarily be equal across any given frequency band, but it will
normally be continuous across the band. This means that some of it will
be within the bandwidth of the signal we are attempting to receive and
decode. If we are very unlucky it will peak within the bandwidth of the
signal.

A very small part of the noise floor is 'cosmic noise', about which we
can do nothing.

Normally the biggest source of noise in a receiving system is the first
active device the signal encounters in the system.

Remember that the level of the noise and the level of the signal aren't
important; it's the ratio between the two that matters. Once that ratio
is set no amount of amplification will improve reception.

But if the noise is generated inside the TV receiver, or in the wire from
aerial to TV, and you amplify the signal before that point, you improve the ratio?

I'm glad that since digital was invented I've stuck mainly to dishes.
Way less problems when you're only picking up from one very specific
direction.

Yes, I've always thought satellite was much easier than terrestrial.

Must cost a lot to put those things up there though.

Pretty Astranomical .

Ill get my coat.

That reminds me of when I was trying to tell a colleague how to pronounce my Greek colleague's name "Asthanostheas" I got as far as "Ast" and he said "Astronomical?" I said "Just call him Thanos" - which was what he seemed to like going by, probably because it was a Greek god.

On Thu, 3 Jan 2019 11:54:50 +0000, rick wrote:

I know currently without distribution amp (10dB gain) the HD channel
break up, SD is OK.

Which sort of indicates a low signal level for the HD MUX(s). Why
though? Have you ever changed the aerial? With all the shuffling
about that has gone on with the clearing fo 800 and 700 MHz, your
aerial may now be the "wrong" group for the frequencies used by the
HD MUXs in your area.

--
Cheers
Dave.

On 03/01/2019 18:48, charles wrote:

Oh dear. Even the first mobile phone signal were higher in frequency the
broadcast tv, The problem lies from the probably lack of filters in the
tv. High level mobile phone signals - froma nearby mast (for instance)
can overload the front end of the tv set.

The LabGear amp contains Class 3 4G filter providing 45dB interference
protection

On 03/01/2019 20:48, Bill Wright wrote:


The first thing a good aerial man will do when called to a telly with
poor reception is check the signal levels.



Which was the point of the OP

On 04/01/2019 21:10, Commander Kinsey wrote:

How long are the cables, and what sort of cable?

Standard Sky cable, 200 metres.

The loss will be 50 to 60dB so yes, you will need line amps. As you say,
they need to be correctly positioned along the cable. Do you use line
amps with built-in equalisation? Do you use direct-burial or sheathed
cable?

It would be technically better to use a large diameter cable such as
CT167, but I realise cost would be a factor.

Bill

On 05/01/2019 13:43, rick wrote:
On 03/01/2019 20:48, Bill Wright wrote:


The first thing a good aerial man will do when called to a telly with
poor reception is check the signal levels.


Which was the point of the OP

Sometimes reiteration is necessary.

Bill

On 04/01/2019 21:13, Commander Kinsey wrote:

Why not? If you're close enough the signal levels can easily be
excessive.

I've never experienced that.* Usually the problem is you're miles from
the nearest transmitter, or there's something in the way (TM Nirvana).
Mobile phones are absolutely terrible for this, presumably due to higher
frequencies that don't travel so far or round corners so easily.

Where are you?

It doesn't sound as if you have a main station nearby.

When I was fixing aerials for rental chains in the 1970s excessive
signal levels were a constant problem in West and South Yorkshire. The
usual tx was Emley Moor, and if it was line-of-sight and you were closer
than 15 miles the signal levels would be +23dBmV (analogue of course) or
more. Really close you might get +35dBmV but it didn't increase much as
you got even closer because of the vertical beamwidth of the tx.

In the 70s and 80s the rental firms mostly used chassis that were
intolerant of levels above +16dBmV (they were also intolerant of levels
below +3dBmV!). That was OK while the sets had a little preset on the
back that was a variable attenuator. But when that was discontinued the
problem became as much financial as technical. Attenuators were 50p. The
gross profit on a new aerial job was £4.75. I resorted to faraday loops.
Most installers resorted to putting one strand of braid onto the centre
pin in the plug.

Bill

On Sat, 5 Jan 2019 16:06:41 +0000, Bill Wright, another mentally challenged,
troll-feeding, senile idiot, blathered:


The loss will be 50 to 60dB so yes, you will need line amps. As you say,
they need to be correctly positioned along the cable. Do you use line
amps with built-in equalisation? Do you use direct-burial or sheathed
cable?

All I see is he's using senile fools like you for his personal
entertainment! LOL

On Sat, 5 Jan 2019 16:25:26 +0000, Bill Wright, another mentally challenged,
troll-feeding, senile idiot, blathered:



Where are you?

He's not all there. And obviously neither are you ...for not noticing it!

On Sat, 05 Jan 2019 16:06:41 -0000, Bill Wright wrote:

On 04/01/2019 21:10, Commander Kinsey wrote:

How long are the cables, and what sort of cable?

Standard Sky cable, 200 metres.

The loss will be 50 to 60dB so yes, you will need line amps. As you say,
they need to be correctly positioned along the cable. Do you use line
amps with built-in equalisation?

Er.... I dunno what that is. I just bought inline amps that are powered off the 12VDC present on the cable from the Sky box. They're tiny little things, not much bigger than the two connectors on each end.

Do you use direct-burial or sheathed
cable?

Just the standard cable everyone has from Sky dish to Sky box at home, but longer. It's not buried, it's going through false ceilings.

It would be technically better to use a large diameter cable such as
CT167, but I realise cost would be a factor.

It seems to work fine with the little amps.

On Sat, 05 Jan 2019 16:25:26 -0000, Bill Wright wrote:

On 04/01/2019 21:13, Commander Kinsey wrote:

Why not? If you're close enough the signal levels can easily be
excessive.

I've never experienced that. Usually the problem is you're miles from
the nearest transmitter, or there's something in the way (TM Nirvana)..
Mobile phones are absolutely terrible for this, presumably due to higher
frequencies that don't travel so far or round corners so easily.

Where are you?

Central Scotland. It's actually worse in the town where the transmitter is, as the tall buildings block the signal.

It doesn't sound as if you have a main station nearby.

When I was fixing aerials for rental chains in the 1970s excessive
signal levels were a constant problem in West and South Yorkshire. The
usual tx was Emley Moor, and if it was line-of-sight and you were closer
than 15 miles the signal levels would be +23dBmV (analogue of course) or
more. Really close you might get +35dBmV but it didn't increase much as
you got even closer because of the vertical beamwidth of the tx.

In the 70s and 80s the rental firms mostly used chassis that were
intolerant of levels above +16dBmV (they were also intolerant of levels
below +3dBmV!). That was OK while the sets had a little preset on the
back that was a variable attenuator. But when that was discontinued the
problem became as much financial as technical. Attenuators were 50p. The
gross profit on a new aerial job was £4.75. I resorted to faraday loops.
Most installers resorted to putting one strand of braid onto the centre
pin in the plug.

It's amazing anything works at all :-)

On 07/01/2019 22:45, Commander Kinsey wrote:
On Sat, 05 Jan 2019 16:06:41 -0000, Bill Wright
wrote:

On 04/01/2019 21:10, Commander Kinsey wrote:

How long are the cables, and what sort of cable?

Standard Sky cable, 200 metres.

The loss will be 50 to 60dB so yes, you will need line amps. As you say,
they need to be correctly positioned along the cable. Do you use line
amps with built-in equalisation?

Er.... I dunno what that is.

Because losses on cable are greater on higher frequencies than on lower
ones, the line amps should really amplifier the higher frequencies more
than the lower ones, to compensate for it. This is called
'equalisation'. Some line amps have a fixed amount of equalisation
('gain slope') and some are adjustable. Have a look at the instructions
for the ones you use. Also look at Triax 370650
http://www.triax.uk/products/satelli...lope-amplifier
Incidentally I have a lot of these surplus and brand new if you want a
bargain.


It seems to work fine with the little amps.

Yes you're generally going to be OK but if you have problems with higher
muxes consider thicker cable and/or equalising line amps.

I hope you make sure no section of the cable is permanently under water...

Bill

On Mon, 7 Jan 2019 23:22:57 +0000, Bill Wright, another mentally challenged,
troll-feeding, senile idiot, blathered:



I hope you make sure no section of the cable is permanently under water...

I hope you will soon realize what a troll-feeding senile asshole you are,
idiot!

On Mon, 07 Jan 2019 23:22:57 -0000, Bill Wright wrote:

On 07/01/2019 22:45, Commander Kinsey wrote:
On Sat, 05 Jan 2019 16:06:41 -0000, Bill Wright
wrote:

On 04/01/2019 21:10, Commander Kinsey wrote:

How long are the cables, and what sort of cable?

Standard Sky cable, 200 metres.

The loss will be 50 to 60dB so yes, you will need line amps. As you say,
they need to be correctly positioned along the cable. Do you use line
amps with built-in equalisation?

Er.... I dunno what that is.

Because losses on cable are greater on higher frequencies than on lower
ones, the line amps should really amplifier the higher frequencies more
than the lower ones, to compensate for it. This is called
'equalisation'. Some line amps have a fixed amount of equalisation
('gain slope') and some are adjustable. Have a look at the instructions
for the ones you use. Also look at Triax 370650
http://www.triax.uk/products/satelli...lope-amplifier
Incidentally I have a lot of these surplus and brand new if you want a
bargain.

I just bought the cheap ones and they seem to work ok.

It seems to work fine with the little amps.

Yes you're generally going to be OK but if you have problems with higher
muxes consider thicker cable and/or equalising line amps.

The signal strength to all boxes is quite satisfactory. Mind you I did also use a very large dish. The management were mildly irritated when they saw the size of it, especially as I didn't tell them I was installing it. It replaced a cable TV line which was damaged by extensive building work, and Telewest or whatever they call themselves refused to fix it without a tremendous fee, plus they wanted to know how we'd been getting their services for free for the last 10 years :-)

I hope you make sure no section of the cable is permanently under water...

If the water got to 12 feet above ground level, we'd have greater concerns.