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  #21  
Old November 29th 16, 05:45 PM posted to uk.tech.digital-tv
James Heaton
external usenet poster
 
Posts: 82
Default Weather effects


"Bill Wright" wrote in message
news
On 28/11/2016 18:20, James Heaton wrote:

Update - noticed no problem with the bedroom telly, same equipment, so
figured it had to be wiring.

Faceplate was loose... couple of tightened screws seems to have solved
it.


You would have disturbed the connection behind the plate, and the flylead,
and the plug/socket connection, and might have accidentally 'fixed' a bad
connection.

It sounds as if reception is marginal anyway. Because of the digital cliff
you wouldn't have any sign of this normally.


Still no idea why it only affected CH59-, or seemed to improve in the
evenings however.


Feeder discontinuities cause standing wave effects that are different for
different frequencies. It's all very random.


Cheers Bill.

c.20km from Tacolneston, loft aerial fitted 2011, with head amp and 4-way
splitter to give a TV point in each room.

I think however the living room - the problematic one - reused the original
70s wiring, whereas the other 3 rooms had new - didn't have TV points other
than lounge before, we relied on set top aerials for bedrooms, and didn't
have a telly point for kitchen/conservatory (I had this mad idea of sitting
in the conservatory watching TV, but it's either like a fridge or a furnace
in there!) Still had a b&w telly in the spare bedroom...

I noticed yesterday - meeting finished early so rather than go back to
office came home for a go on the wifi (types carefully... one vowel out from
something very different...) I put the living room telly on whilst opened
post then went through to bedroom where the desk is. Channel 4 was sh1te in
the living room but fine in the bedroom. So led me to suspect the
socket/wiring - do you think I'm on the right lines to suspect the older
wiring?

James

  #22  
Old November 29th 16, 06:43 PM posted to uk.tech.digital-tv
Woody[_5_]
external usenet poster
 
Posts: 1,638
Default Weather effects


"James Heaton" wrote in message
news

"Bill Wright" wrote in message
news
On 28/11/2016 18:20, James Heaton wrote:

Update - noticed no problem with the bedroom telly, same
equipment, so
figured it had to be wiring.

Faceplate was loose... couple of tightened screws seems to have
solved it.


You would have disturbed the connection behind the plate, and the
flylead, and the plug/socket connection, and might have
accidentally 'fixed' a bad connection.

It sounds as if reception is marginal anyway. Because of the
digital cliff you wouldn't have any sign of this normally.


Still no idea why it only affected CH59-, or seemed to improve in
the
evenings however.


Feeder discontinuities cause standing wave effects that are
different for different frequencies. It's all very random.


Cheers Bill.

c.20km from Tacolneston, loft aerial fitted 2011, with head amp and
4-way splitter to give a TV point in each room.

I think however the living room - the problematic one - reused the
original 70s wiring, whereas the other 3 rooms had new - didn't have
TV points other than lounge before, we relied on set top aerials for
bedrooms, and didn't have a telly point for kitchen/conservatory (I
had this mad idea of sitting in the conservatory watching TV, but
it's either like a fridge or a furnace in there!) Still had a b&w
telly in the spare bedroom...

I noticed yesterday - meeting finished early so rather than go back
to office came home for a go on the wifi (types carefully... one
vowel out from something very different...) I put the living room
telly on whilst opened post then went through to bedroom where the
desk is. Channel 4 was sh1te in the living room but fine in the
bedroom. So led me to suspect the socket/wiring - do you think I'm
on the right lines to suspect the older wiring?



I would be inclined to suspect the cable. Older (usually brown) TV
coax had a very loose open weave braid which provided continuity but
very little screening making the cable susceptible to pickup.
Replacing it with something like PF100 will certainly remove any
possibility of cable pickup.

However it puzzles me. ITV/4/five and others are all transmitted on
the same mux, so if Ch4 is poor I would have expected there to be
issues with the other stations as well. Have you tried swapping TVs
around - it is always possible the living room TV has a problem with
that particular frequency? Also have you looked at the menu on each TV
to look at what sort of signal level you are getting? If all are
showing a maximum signal you might have an overloaded masthead amp
which the other TVs deal with better than the lounge TV. Equally the
lounge TV may be significantly more sensitive than the others and just
that one TV be overloaded. Try fitting a 12dB attenuator on the aerial
input to the lounge TV to see if it helps (assuming it is still
playing up once you have replaced tha downlead.) Said attenuator costs
4.99 from Maplins or less elsewhere.

The other possibility is that, being on 59-, your are getting 4G
interference from a nearby mast. If there is a mast causing such a
problem you should be able to get filters for each TV free of charge
from at800.tv (no www) - look on the web.

I'm still puzzled why it is only one station though.


--
Woody

harrogate3 at ntlworld dot com


  #23  
Old November 29th 16, 08:38 PM posted to uk.tech.digital-tv
James Heaton
external usenet poster
 
Posts: 82
Default Weather effects


"Woody" wrote in message
news

"James Heaton" wrote in message
news

"Bill Wright" wrote in message
news
On 28/11/2016 18:20, James Heaton wrote:

Update - noticed no problem with the bedroom telly, same equipment, so
figured it had to be wiring.

Faceplate was loose... couple of tightened screws seems to have solved
it.

You would have disturbed the connection behind the plate, and the
flylead, and the plug/socket connection, and might have accidentally
'fixed' a bad connection.

It sounds as if reception is marginal anyway. Because of the digital
cliff you wouldn't have any sign of this normally.


Still no idea why it only affected CH59-, or seemed to improve in the
evenings however.

Feeder discontinuities cause standing wave effects that are different
for different frequencies. It's all very random.


Cheers Bill.

c.20km from Tacolneston, loft aerial fitted 2011, with head amp and 4-way
splitter to give a TV point in each room.

I think however the living room - the problematic one - reused the
original 70s wiring, whereas the other 3 rooms had new - didn't have TV
points other than lounge before, we relied on set top aerials for
bedrooms, and didn't have a telly point for kitchen/conservatory (I had
this mad idea of sitting in the conservatory watching TV, but it's either
like a fridge or a furnace in there!) Still had a b&w telly in the spare
bedroom...

I noticed yesterday - meeting finished early so rather than go back to
office came home for a go on the wifi (types carefully... one vowel out
from something very different...) I put the living room telly on whilst
opened post then went through to bedroom where the desk is. Channel 4
was sh1te in the living room but fine in the bedroom. So led me to
suspect the socket/wiring - do you think I'm on the right lines to
suspect the older wiring?



I would be inclined to suspect the cable. Older (usually brown) TV coax
had a very loose open weave braid which provided continuity but very
little screening making the cable susceptible to pickup. Replacing it with
something like PF100 will certainly remove any possibility of cable
pickup.

However it puzzles me. ITV/4/five and others are all transmitted on the
same mux, so if Ch4 is poor I would have expected there to be issues with
the other stations as well. Have you tried swapping TVs around - it is
always possible the living room TV has a problem with that particular
frequency? Also have you looked at the menu on each TV to look at what
sort of signal level you are getting? If all are showing a maximum signal
you might have an overloaded masthead amp which the other TVs deal with
better than the lounge TV. Equally the lounge TV may be significantly more
sensitive than the others and just that one TV be overloaded. Try fitting
a 12dB attenuator on the aerial input to the lounge TV to see if it helps
(assuming it is still playing up once you have replaced tha downlead.)
Said attenuator costs 4.99 from Maplins or less elsewhere.

The other possibility is that, being on 59-, your are getting 4G
interference from a nearby mast. If there is a mast causing such a problem
you should be able to get filters for each TV free of charge from at800.tv
(no www) - look on the web.

I'm still puzzled why it is only one station though.


Sorry for confusion - it's all CH59- channels, C4 is just the one I mainly
watch if I'm home in the afternoon (perm from Countdown/15 to 1/DonD/Come
Dine, all quite useful background noise for writing email.)

I can't see what the cable is as it's chased into the wall behind the
faceplate... But house was built c.77 and I know the cable wasn't changed
as I didn't have to redecorate...

On the Humax 9300 boxes we use, living room box is solidly 81 strength 100
quality on all muxes other than 59 - which was 80 strength and quality
anywhere between 10 and 100, wavering badly. The 59s were rock solid 80/100
in the bedroom on another 9300 box.

Still running 'fine and true' since tightening up the faceplate which even
more so makes me suspect the cable...

Cheers James


  #24  
Old November 29th 16, 09:25 PM posted to uk.tech.digital-tv
Woody[_5_]
external usenet poster
 
Posts: 1,638
Default Weather effects


"James Heaton" wrote in message
news

"Woody" wrote in message
news

"James Heaton" wrote in message
news

"Bill Wright" wrote in message
news On 28/11/2016 18:20, James Heaton wrote:

Update - noticed no problem with the bedroom telly, same
equipment, so
figured it had to be wiring.

Faceplate was loose... couple of tightened screws seems to have
solved it.

You would have disturbed the connection behind the plate, and the
flylead, and the plug/socket connection, and might have
accidentally 'fixed' a bad connection.

It sounds as if reception is marginal anyway. Because of the
digital cliff you wouldn't have any sign of this normally.


Still no idea why it only affected CH59-, or seemed to improve
in the
evenings however.

Feeder discontinuities cause standing wave effects that are
different for different frequencies. It's all very random.

Cheers Bill.

c.20km from Tacolneston, loft aerial fitted 2011, with head amp
and 4-way splitter to give a TV point in each room.

I think however the living room - the problematic one - reused the
original 70s wiring, whereas the other 3 rooms had new - didn't
have TV points other than lounge before, we relied on set top
aerials for bedrooms, and didn't have a telly point for
kitchen/conservatory (I had this mad idea of sitting in the
conservatory watching TV, but it's either like a fridge or a
furnace in there!) Still had a b&w telly in the spare bedroom...

I noticed yesterday - meeting finished early so rather than go
back to office came home for a go on the wifi (types carefully...
one vowel out from something very different...) I put the living
room telly on whilst opened post then went through to bedroom
where the desk is. Channel 4 was sh1te in the living room but
fine in the bedroom. So led me to suspect the socket/wiring - do
you think I'm on the right lines to suspect the older wiring?



I would be inclined to suspect the cable. Older (usually brown) TV
coax had a very loose open weave braid which provided continuity
but very little screening making the cable susceptible to pickup.
Replacing it with something like PF100 will certainly remove any
possibility of cable pickup.

However it puzzles me. ITV/4/five and others are all transmitted on
the same mux, so if Ch4 is poor I would have expected there to be
issues with the other stations as well. Have you tried swapping TVs
around - it is always possible the living room TV has a problem
with that particular frequency? Also have you looked at the menu on
each TV to look at what sort of signal level you are getting? If
all are showing a maximum signal you might have an overloaded
masthead amp which the other TVs deal with better than the lounge
TV. Equally the lounge TV may be significantly more sensitive than
the others and just that one TV be overloaded. Try fitting a 12dB
attenuator on the aerial input to the lounge TV to see if it helps
(assuming it is still playing up once you have replaced tha
downlead.) Said attenuator costs 4.99 from Maplins or less
elsewhere.

The other possibility is that, being on 59-, your are getting 4G
interference from a nearby mast. If there is a mast causing such a
problem you should be able to get filters for each TV free of
charge from at800.tv (no www) - look on the web.

I'm still puzzled why it is only one station though.


Sorry for confusion - it's all CH59- channels, C4 is just the one I
mainly watch if I'm home in the afternoon (perm from Countdown/15 to
1/DonD/Come Dine, all quite useful background noise for writing
email.)

I can't see what the cable is as it's chased into the wall behind
the faceplate... But house was built c.77 and I know the cable
wasn't changed as I didn't have to redecorate...

On the Humax 9300 boxes we use, living room box is solidly 81
strength 100 quality on all muxes other than 59 - which was 80
strength and quality anywhere between 10 and 100, wavering badly.
The 59s were rock solid 80/100 in the bedroom on another 9300 box.

Still running 'fine and true' since tightening up the faceplate
which even more so makes me suspect the cable...


The fact that the quality is unstable suggests that the cable might
actually be bent or crushed, so there may be no alternative but to
replace it.

If the box concerned is on an outside wall you could drill through the
back of the box and run a new cable on the outside wall. The fact that
it is all channels on the mux and that having (effectively) moved the
box seems to support the opinion that it is a cable issue.

You can buy PF100 or similar from Screwfix or Toolstation in 25m
reels - you can never have enough spare cable - along with the
necessay 7mm cable clips. Do remember if you change the cable yourself
to run it down the wall slightly one side of the incoming hole such
that you can loop the cable down and back up into the hole so that
water drips off it. If you drill a hole through from the inside to the
outside it is also a good idea to slope it downwards slightly again to
stop water ingress particularly to keep it away from cavity insulation
which in 1977 might well have been urea foam which is notorious for
bridging the cavity and causing damp.


--
Woody

harrogate3 at ntlworld dot com


  #25  
Old November 30th 16, 01:55 AM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 1,622
Default Weather effects

On 29/11/2016 18:45, James Heaton wrote:


I noticed yesterday - meeting finished early so rather than go back to
office came home for a go on the wifi (types carefully... one vowel out
from something very different...) I put the living room telly on whilst
opened post then went through to bedroom where the desk is. Channel 4
was sh1te in the living room but fine in the bedroom. So led me to
suspect the socket/wiring - do you think I'm on the right lines to
suspect the older wiring?


Yes, but as any good DI will tell you, sometimes suspects prove
innocent, against all probabilities.

Firstly are you sure that the tv is correctly tuned?

If the suspect cable has evidence of internal damp, such as discoloured
dielectric or conductors, replace it.

Otherwise, easy possibilities should be eliminated first.

I'd swap the outputs from the splitter around, moving to suspect cable
to a different output. Just in case the splitter is faulty. Check the
connection at the splitter.

Next replace the flylead and tv set at the suspect outlet (temporarily).

Next you will have to replace the cable. Use a cable with a copper foil
and copper braid.

Bill

  #26  
Old November 30th 16, 06:17 PM posted to uk.tech.digital-tv
James Heaton
external usenet poster
 
Posts: 82
Default Weather effects


"Bill Wright" wrote in message
news
On 29/11/2016 18:45, James Heaton wrote:


I noticed yesterday - meeting finished early so rather than go back to
office came home for a go on the wifi (types carefully... one vowel out
from something very different...) I put the living room telly on whilst
opened post then went through to bedroom where the desk is. Channel 4
was sh1te in the living room but fine in the bedroom. So led me to
suspect the socket/wiring - do you think I'm on the right lines to
suspect the older wiring?


Yes, but as any good DI will tell you, sometimes suspects prove innocent,
against all probabilities.

Firstly are you sure that the tv is correctly tuned?

If the suspect cable has evidence of internal damp, such as discoloured
dielectric or conductors, replace it.

Otherwise, easy possibilities should be eliminated first.

I'd swap the outputs from the splitter around, moving to suspect cable to
a different output. Just in case the splitter is faulty. Check the
connection at the splitter.

Next replace the flylead and tv set at the suspect outlet (temporarily).

Next you will have to replace the cable. Use a cable with a copper foil
and copper braid.


Cheers all for the helpful suggestions - will file away for next time it
goes wrong.

Wiring is on a party wall unfortunately so think it won't be as simple as
Woody suggested.

Will try Bill's simple solutions first...

James


 




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