Ping Bill Wright: digital airyuls

On Wednesday, July 4th, 2012, at 14:49:34h +0100, Bill Wright advised:

Soft living.

There may very well be an element of truth to that.

Move the government to Salford where the air is fresher and colder.

Not such an impossible task as one may think for those with
organisational abilities.

The Republic of Korea is in the process of moving its administrative
capital to Sejong, 120 kilometres to the south of Seoul.

http://www.bbc.co.UK/news/world-asia-18670195

http://www.voanews.COM/content/south_korea_opens_new_government_hub/1352597.html

Certainly if major government departments were to be moved to the
City of Salford, they would have easy access to the BBC Breakfast News show.

On 01/07/2012 08:37, charles wrote:
In .domain,
Paul wrote:
We were about to embark at Dover, when (Bill Wright)
came up to me and whispered:

I
can see no advantage in using CT125 where signal levels do not
require it,

18dB attenation per 100m, against 26dB for CT100. That's not a small
amount, that's CT125 offering nearly 3 times the signal at receiver...

if you use 100m of downlead. That's quite rare.


incidentally i have just come back from Derbyshire

I was cycling on the Monsal Trail where I came upon a bridge with a high
gain aerial on a pole that was at my head hieght.

I looked over the edge of the bridge and saw a valley with a house at
the bottom.

The high gain aerial was on a 3m pole with a FM "halo" and a FCE
masthead box (Aerial amp and combiner?)

A single CT100 co-ax snaked from the FCE masthead box through the trees
down to this house at the bottom of the valley..... must have been a
good 50 metres of downlead easily.

The aerial was on a relay Tx judging by its vertical element

It would be easy for a miscreant to snap the high gain aerial off, thus
robbing the house occupants of Freeview lite.....

On 04/07/2012 01:30, Bill Wright wrote:

Those figures are wrong.

Agreed.

Here it is from one of the many more definitive
sources: https://dl.dropbox.com/u/11023364/0000.jpg

And another:
http://www.webro.com/tv-satellite/tv...gital-cables2/

A simple sanity check you can apply is that the attenuation in dB is, to
a good approximation, directly proportional to the RF resistance of the
conductors. Since the RF resistance is inversely proportional to the
conductor circumference (not to the cross sectional area, due to skin
effect) the attenuation in dB is inversely proportional to the nominal
cable diameter. Hence any given length of '125'cable should have about
0.8 times the dB loss of a '100' cable of similar construction.

--
Andy

On 03/07/2012 23:57, tony sayer wrote:
In article , Paul
Cummins scribeth thus

Larger aerial or a phased array and, for a run that long, a much less
lossy and less flexible cable.

So not a simple amp to overcome cable loss?..

I wonder if he uses the same approach for satellite - oversize dish and
a run of silver plated WG17 to an indoor LNB?

--
Andy

Andy Wade wrote:

A simple sanity check you can apply is that the attenuation in dB is, to
a good approximation, directly proportional to the RF resistance of the
conductors. Since the RF resistance is inversely proportional to the
conductor circumference (not to the cross sectional area, due to skin
effect) the attenuation in dB is inversely proportional to the nominal
cable diameter. Hence any given length of '125'cable should have about
0.8 times the dB loss of a '100' cable of similar construction.

That's interesting.

Bill

tony sayer wrote:

Bill Wright scribeth thus

In state-run prisons a massive amount of money has been spent on totally
pointless systems that convert DTT to analogue for distribution.

Why?, Is it because the powers that be don't want them to watch certain
channels?..

In at least one state-run establishment (but not a prison) with
non-voluntary residents, the TV distribution of the "wanted" channels is
by IP multicast on the LAN.

In article , Bill Wright
scribeth thus
Andy Wade wrote:

A simple sanity check you can apply is that the attenuation in dB is, to
a good approximation, directly proportional to the RF resistance of the
conductors. Since the RF resistance is inversely proportional to the
conductor circumference (not to the cross sectional area, due to skin
effect) the attenuation in dB is inversely proportional to the nominal
cable diameter. Hence any given length of '125'cable should have about
0.8 times the dB loss of a '100' cable of similar construction.

That's interesting.

Bill

Yes, we use from time to time such cables as Andrews LDF5-50 which is
appx just over an inch in diameter. The inner is around 9.1 outside dia
but hollow at 7.6 inner in order to save cost and weight and also to
increase the surface area for that very reason...

At 860 MHz its rated at 3.78 dB loss per 100 metres and can carry a
measly 2.4 kW;!..
--
Tony Sayer

On 05/07/2012 11:40, tony sayer wrote:
Yes, we use from time to time such cables as Andrews LDF5-50 which is
appx just over an inch in diameter. The inner is around 9.1 outside dia
but hollow at 7.6 inner in order to save cost and weight and also to
increase the surface area for that very reason...

At 860 MHz its rated at 3.78 dB loss per 100 metres and can carry a
measly 2.4 kW;!..


Is that Russ Andrews? :P

Andy

In article , Andy Champ
scribeth thus
On 05/07/2012 11:40, tony sayer wrote:
Yes, we use from time to time such cables as Andrews LDF5-50 which is
appx just over an inch in diameter. The inner is around 9.1 outside dia
but hollow at 7.6 inner in order to save cost and weight and also to
increase the surface area for that very reason...

At 860 MHz its rated at 3.78 dB loss per 100 metres and can carry a
measly 2.4 kW;!..


Is that Russ Andrews? :P

Andy


No!, its not as expensive as Russ would have it at. This is a near
equivalent...

http://www.broadcastwarehouse.com/eupen/7/8-inch-
ec5-50-cable/427/product

Russ would prolly be sellin the super low loss;!..

http://www.broadcastwarehouse.com/eupen/1+5/8-inch-
ec7-50-cable/596/product
--
Tony Sayer

"Bill Wright" wrote in message
...
tony sayer wrote:
In article , Bill Wright

scribeth thus
J G Miller wrote:
On Tuesday, July 3rd, 2012, at 22:32:00h +0100, Paul Cummins
wrote:

AS an example (not my work) the installation at HMP
Winchester has 4
antennas.
You mean to say that Brenda's guests, who are denied
conjugal rights,
do not even get satellite TV?
In state-run prisons a massive amount of money has been spent
on totally pointless systems that convert DTT to analogue for
distribution.

Bill

Why?, Is it because the powers that be don't want them to
watch certain
channels?..
No. It's the result of technical ignorance and muddled
thinking.

Bill


Actually Bill, Tony is right. It is so that the Powers That Be
can control who watches what now there are so many channels, and
also so that they can still show analogue Prison TV. It also
means that the TV's that the lags have had for years will still
work (many are so old they don't have SCART having been passed
down the chain as others have departed,) else someone would have
to pay for DTTV boxes and have to keep them updated. Much better
to be 'in control.'


--
Woody

harrogate three at ntlworld dot com