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uk.tech.digital-tv (Digital TV - General) (uk.tech.digital-tv) Discussion of all matters technical in origin related to the reception of digital television transmissions, be they via satellite, terrestrial or cable. Advertising is forbidden, with no exceptions.

BBC News CHannel 107



 
 
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  #21  
Old March 27th 18, 07:35 PM posted to uk.tech.digital-tv
Woody[_5_]
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Posts: 1,865
Default BBC News CHannel 107


"Bill Wright" wrote in message
news
On 27/03/2018 08:58, Woody wrote:

If an aerial is receiving a useable signal on a side lobe it
suggests
that there is too much incoming from the directed source. This
means
either too much aerial system gain (with or without a masthead amp)
or
a very sensitive TV.


What do you mean by 'directed source'?



The transmitter wot the aerial is pointed at?




--
Woody

harrogate3 at ntlworld dot com


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  #22  
Old March 27th 18, 07:38 PM posted to uk.tech.digital-tv
Woody[_5_]
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Posts: 1,865
Default BBC News CHannel 107


"Mark Carver" wrote in message
...
On 27/03/2018 16:46, Chris Youlden wrote:
On 26/03/2018 17:40, charles wrote:


It depended, I would think, on how much of CP's signal diffracted
over the South Downs, but UHF could do that. It wouldn't have been
reliable, though.


I've heard other stories of Bilsdale being received in Blackpool,
same
effect ?

--



No, more likely a gap in the Pennines just at the right point plus it
is A group so the signal will travel better.

One of our managers used to live in Garforth east of Leeds and he
could get Winter Hill solid 24/365. His neighbour on one side could
get the same, but the neighbour on the other side could not
(bungalows, aerials on gable end, sideways on to WH.)


--
Woody

harrogate3 at ntlworld dot com


  #23  
Old March 27th 18, 08:13 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
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Posts: 2,448
Default BBC News CHannel 107

On 27/03/2018 16:58, Mark Carver wrote:
On 27/03/2018 16:46, Chris Youlden wrote:
On 26/03/2018 17:40, charles wrote:


It depended, I would think, on how much of CP's signal diffracted over
the South Downs, but UHF could do that. It wouldn't have been
reliable, though.


I've heard other stories of Bilsdale being received in Blackpool, same
effect ?

See the story of the IBA adaptive array on the Channel Islands. One
issue was Bilsdale causing problems.

Bill
  #24  
Old March 27th 18, 08:15 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
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Posts: 2,448
Default BBC News CHannel 107

On 27/03/2018 20:38, Woody wrote:
"Mark Carver" wrote in message
...
On 27/03/2018 16:46, Chris Youlden wrote:
On 26/03/2018 17:40, charles wrote:


It depended, I would think, on how much of CP's signal diffracted
over the South Downs, but UHF could do that. It wouldn't have been
reliable, though.


I've heard other stories of Bilsdale being received in Blackpool,
same
effect ?

--



No, more likely a gap in the Pennines just at the right point plus it
is A group so the signal will travel better.

One of our managers used to live in Garforth east of Leeds and he
could get Winter Hill solid 24/365. His neighbour on one side could
get the same, but the neighbour on the other side could not
(bungalows, aerials on gable end, sideways on to WH.)


Yes, there's a housing estate in Ferrybridge where they can get Winter
Hill. And of course I can get it here but only at a certain height. Not
on the roof. And the problem wasn't CCI when I last tried.

Bill
  #25  
Old March 27th 18, 08:22 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default BBC News CHannel 107

On 27/03/2018 20:35, Woody wrote:
"Bill Wright" wrote in message
news
On 27/03/2018 08:58, Woody wrote:

If an aerial is receiving a useable signal on a side lobe it
suggests
that there is too much incoming from the directed source. This
means
either too much aerial system gain (with or without a masthead amp)
or
a very sensitive TV.


What do you mean by 'directed source'?



The transmitter wot the aerial is pointed at?


Ah. I wondered if that's what you meant. In that case, how does the
field strength of the wanted signal influence reception of another
signal via a side lobe? I think what you were trying to say is that if
the wanted signal is strong, advantage should be taken of that fact by
using less signal amplification or even an attenuator. But not, as you
suggest, by reducing aerial gain because that will almost certainly
reduce the ratio between the wanted signal and the signal received on
the side lobe.

Bill
  #26  
Old March 27th 18, 11:42 PM posted to uk.tech.digital-tv
Graham.[_12_]
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Posts: 472
Default BBC News CHannel 107

On 26/03/2018 23:38, NY wrote:

What I want to know is how the hell I once got spurious multiplexes near
Leyburn from Emley Moor (or one of its relays) when the reception
predictor says the only thing that my aerial should be able to see (from
*any* direction) is Bilsdale.


Emley does seem to penetrate further than predictions would indicate in
that area.

And that was with a narrow-band aerial
(whatever group Bilsdale used in analogue days, before we had the aerial
changed to wideband) pointing at Bilsdale, so whatever was breaking
through was a) roughly on the axis of the aerial (due to its polar
response);


The polar response of an aerial when receiving an out-of-band signal is
almost random.

and b) within the sweet-spot of a Bilsdale grouped aerial


'Sweet spot' has many meanings (some of them unsuitable for a family
newsgroup) but it doesn't mean 'the design bandwidth of an aerial'.
Some Americans do use it in an RF context, but not to mean that.


Its the best bit of the crystal for the cat's whisker.


--

Graham.
%Profound_observation%
  #27  
Old March 28th 18, 06:53 AM posted to uk.tech.digital-tv
Mark Carver[_2_]
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Posts: 439
Default BBC News CHannel 107

On 27/03/2018 21:13, Bill Wright wrote:
On 27/03/2018 16:58, Mark Carver wrote:
On 27/03/2018 16:46, Chris Youlden wrote:
On 26/03/2018 17:40, charles wrote:


It depended, I would think, on how much of CP's signal diffracted
over the South Downs, but UHF could do that. It wouldn't have been
reliable, though.


I've heard other stories of Bilsdale being received in Blackpool, same
effect ?

See the story of the IBA adaptive array on the Channel Islands. One
issue was Bilsdale causing problems.


Oh, I know yes, it also caused problems when Heathfield took an off air
RBL feed from Crystal P (which was co-channel). In the end the Beeb
provided a microwave link feed for it via Wrotham I think ?

When C4 started (on Ch 23) that was out of band for original
Rhode and Schwarz aerial system [1] so that was replaced
with a wider bandwidth EMI slot system. I think that had a sharper
beam tilt, to cause less grief 'way down south' ?

Bilsdale story:-
http://tx.mb21.co.uk/gallery/gallery...44&pageid=2145

[1] You see, it's not just at the receiving end you need to replace
your aerial due to frequency changes etc !

--
Mark
Please replace invalid and invalid with gmx and net to reply.
  #28  
Old March 28th 18, 12:58 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default BBC News CHannel 107

On 28/03/2018 00:42, Graham. wrote:

'Sweet spot' has many meanings (some of them unsuitable for a family
newsgroup) but it doesn't mean 'the design bandwidth of an aerial'.
Some Americans do use it in an RF context, but not to mean that.


Its the best bit of the crystal for the cat's whisker.


I didn't want to show my age...

Bill
  #29  
Old March 28th 18, 01:01 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default BBC News CHannel 107

On 28/03/2018 07:53, Mark Carver wrote:

When C4 started (on Ch 23) that was out of band for original
Rhode and Schwarz aerial system [1] so that was replaced
with a wider bandwidth EMI slot system. I think that had a sharper
beam tilt, to cause less grief 'way down south' ?

Bilsdale story:-
http://tx.mb21.co.uk/gallery/gallery...44&pageid=2145

[1]* You see, it's not just at the receiving end you need to replace
your aerial due to frequency changes etc !


Didn't know that. Farthest south I've ever used Bilsdale for a permanent
installation was, I think, Mansfield.

Here at Micklebring Bilsdale is line-of-sight.

Bill
  #30  
Old March 28th 18, 02:02 PM posted to uk.tech.digital-tv
NY
external usenet poster
 
Posts: 1,329
Default BBC News CHannel 107

"Bill Wright" wrote in message
news
On 28/03/2018 07:53, Mark Carver wrote:

When C4 started (on Ch 23) that was out of band for original
Rhode and Schwarz aerial system [1] so that was replaced
with a wider bandwidth EMI slot system. I think that had a sharper
beam tilt, to cause less grief 'way down south' ?

Bilsdale story:-
http://tx.mb21.co.uk/gallery/gallery...44&pageid=2145

[1] You see, it's not just at the receiving end you need to replace
your aerial due to frequency changes etc !


Didn't know that. Farthest south I've ever used Bilsdale for a permanent
installation was, I think, Mansfield.

Here at Micklebring Bilsdale is line-of-sight.


I'm amazed how far north east Emley Moor goes. When we were looking at a
house in Snainton, not far from Scarborough, they got TV from Emley Moor.
Bilsdale was a complete non-starter because of local hills and Scarborough
Oliver's Mount was almost completely obstructed.

 




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