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Default "tuning" in a Freeview digital TV set-top box

You know that business of old, with indoor rabbit ear antenna. Ask someone
to hold the aerial while you monitor the picture and the best position is
with your assistant holding the aerial at an impossible arm's length , in
middle space.

The same with one of these digital boxes. Good external Yaggi and downlead
and the signal bar is 80 to 100 percent on all stationss except two. Moving
the plastic cased box around there is a point , in mid space, where the "no
signal" box disappears and the signal bar goes to 20 to 30 percent on those
channels. Have to be barefoot to work, also wearing a glove nullifies the
effect. Any advice on how to progress, grounded aluminium around the box?
local ghosting effect ? if so why only 2 stations affected out of the 10 or
more on that one multiplexed UHF channel


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




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Default "tuning" in a Freeview digital TV set-top box


"N Cook" wrote in message
...
You know that business of old, with indoor rabbit ear antenna. Ask someone
to hold the aerial while you monitor the picture and the best position is
with your assistant holding the aerial at an impossible arm's length , in
middle space.

The same with one of these digital boxes. Good external Yaggi and downlead
and the signal bar is 80 to 100 percent on all stationss except two.
Moving
the plastic cased box around there is a point , in mid space, where the
"no
signal" box disappears and the signal bar goes to 20 to 30 percent on
those
channels. Have to be barefoot to work, also wearing a glove nullifies the
effect. Any advice on how to progress, grounded aluminium around the box?
local ghosting effect ? if so why only 2 stations affected out of the 10
or
more on that one multiplexed UHF channel


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/


But is it a proper wideband digital antenna ? Some of the multiplexes that
'belong' together, are at opposite ends of the band, so a wideband antenna
is essential. A 'channelised' type, when added to cable slope and other
assorted vagaries of a 'standard' analogue setup, can result in such
oddities as individual channel suckouts, as you are describing.

Where's Bill Wright ? We need him in on this one. He'd put you straight.

Arfa


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Default "tuning" in a Freeview digital TV set-top box

In article ,
N Cook wrote:
The same with one of these digital boxes. Good external Yaggi and
downlead and the signal bar is 80 to 100 percent on all stationss except
two. Moving the plastic cased box around there is a point , in mid
space, where the "no signal" box disappears and the signal bar goes to
20 to 30 percent on those channels. Have to be barefoot to work, also
wearing a glove nullifies the effect. Any advice on how to progress,
grounded aluminium around the box? local ghosting effect ? if so why
only 2 stations affected out of the 10 or more on that one multiplexed
UHF channel


If there's that much pickup on the box or downlead, there's something
wrong. Short in the co-ax or connector?

--
*I never drink anything stronger than gin before breakfast *

Dave Plowman London SW
To e-mail, change noise into sound.
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Default "tuning" in a Freeview digital TV set-top box



Multipath?


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Default "tuning" in a Freeview digital TV set-top box

Dave Plowman (News) wrote in message
...
In article ,
N Cook wrote:
The same with one of these digital boxes. Good external Yaggi and
downlead and the signal bar is 80 to 100 percent on all stationss except
two. Moving the plastic cased box around there is a point , in mid
space, where the "no signal" box disappears and the signal bar goes to
20 to 30 percent on those channels. Have to be barefoot to work, also
wearing a glove nullifies the effect. Any advice on how to progress,
grounded aluminium around the box? local ghosting effect ? if so why
only 2 stations affected out of the 10 or more on that one multiplexed
UHF channel


If there's that much pickup on the box or downlead, there's something
wrong. Short in the co-ax or connector?

--
*I never drink anything stronger than gin before breakfast *

Dave Plowman London SW
To e-mail, change noise into sound.



Looking a bit deeper the main problem stations are on UHF Channel 33, Mux D
the highest frequency of the local (Rowridge) group.
Unless anyone knows how to push the problem into the totally junk and so
deleted shopping channels, looks like a new yagi and downlead.
A near neighbour has no problem with any freeview channel with a relatively
short Yaggi in his loft space.
The immediate neighbour, so yaggi only a couple of feet away and parallel,
uses a line powered headend amp which perhaps could be
radiating/interfering/coupling. Perhaps a different mounting position should
be considered also.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




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Default "tuning" in a Freeview digital TV set-top box

In article ,
N Cook wrote:
Looking a bit deeper the main problem stations are on UHF Channel 33,
Mux D the highest frequency of the local (Rowridge) group. Unless anyone
knows how to push the problem into the totally junk and so deleted
shopping channels, looks like a new yagi and downlead.


If you can ascertain the age of the aerial in certain areas, as has been
said, it may not be suitable for all the FreeView muxes - in the same way
as some weren't suitable for Ch5. It all depends on the frequencies used
locally. In the London area the muxes are within the existing grouping -
you'd need to look it up for Rowridge. There are probably some yagis
still in use from the early BBC2 days which were peaked for just the one
frequency.

A near neighbour has no problem with any freeview channel with a
relatively short Yaggi in his loft space.


Could be a wideband type.

The immediate neighbour, so yaggi only a couple of
feet away and parallel, uses a line powered headend amp which perhaps
could be radiating/interfering/coupling. Perhaps a different mounting
position should be considered also.


A few feet can make a difference. But while you're up there you might as
well change it. If you're in a reasonable field strength area go for a log
beam. Nice smooth response and good DP. And use a decent satellite cable
rather than plain UHF. I like these people for such things - and their
strap chimney mounting is a delight to use.

https://www.blake-uk.com/page/aerial_dml

--
*Gravity is a myth, the earth sucks *

Dave Plowman London SW
To e-mail, change noise into sound.
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Default "tuning" in a Freeview digital TV set-top box


"Dave Plowman (News)" wrote in message
...
In article ,
N Cook wrote:
Looking a bit deeper the main problem stations are on UHF Channel 33,
Mux D the highest frequency of the local (Rowridge) group. Unless anyone
knows how to push the problem into the totally junk and so deleted
shopping channels, looks like a new yagi and downlead.


If you can ascertain the age of the aerial in certain areas, as has been
said, it may not be suitable for all the FreeView muxes - in the same way
as some weren't suitable for Ch5. It all depends on the frequencies used
locally. In the London area the muxes are within the existing grouping -
you'd need to look it up for Rowridge. There are probably some yagis
still in use from the early BBC2 days which were peaked for just the one
frequency.

A near neighbour has no problem with any freeview channel with a
relatively short Yaggi in his loft space.


Could be a wideband type.

The immediate neighbour, so yaggi only a couple of
feet away and parallel, uses a line powered headend amp which perhaps
could be radiating/interfering/coupling. Perhaps a different mounting
position should be considered also.


A few feet can make a difference. But while you're up there you might as
well change it. If you're in a reasonable field strength area go for a log
beam. Nice smooth response and good DP. And use a decent satellite cable
rather than plain UHF. I like these people for such things - and their
strap chimney mounting is a delight to use.

https://www.blake-uk.com/page/aerial_dml

--
*Gravity is a myth, the earth sucks *

Dave Plowman London SW
To e-mail, change noise into sound.



I agree on all points. A decent log periodic is the way to go. Also remember
that any amp, if required, must also be 'digital specified' which in
practice means wideband and masthead. CT100 is a good choice for the coax.

A different position for the aerial can make all the difference. Many years
ago, in the early UHF colour days, I was installing a TV in a village that
was a very difficult reception area, being in a complete hollow in the
countryside. We arranged for the aerial man to be there at the same time as
us. I clearly remember him walking backwards and forwards along the house's
ridge line, with an aerial 6 foot long on a 10 foot pole in his arms looking
for somewhere to get a signal. Success was the difference between a chimney
stack on one end of the house, and another one thirty feet away at the other
end ...

Arfa


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Default "tuning" in a Freeview digital TV set-top box


"Charles" wrote in message
. ..


Multipath?


Well, of course Charles, we all know in the UK that digital doesn't suffer
from multipath. In fact it's immune from everything ! The government says so
.... d;~}

Arfa


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Default "tuning" in a Freeview digital TV set-top box



"Arfa Daily" wrote in message
...

"Charles" wrote in message
. ..


Multipath?


Well, of course Charles, we all know in the UK that digital doesn't suffer
from multipath. In fact it's immune from everything ! The government says
so ... d;~}


Sigh. Our government "devolved" from yours.

I find multipath to be a more serious problem (compared to analog) with many
digital transmission formats. But, what do I know ... I don't work for the
government.


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Default "tuning" in a Freeview digital TV set-top box


"Charles" wrote in message
. ..


"Arfa Daily" wrote in message
...

"Charles" wrote in message
. ..


Multipath?


Well, of course Charles, we all know in the UK that digital doesn't
suffer from multipath. In fact it's immune from everything ! The
government says so ... d;~}


Sigh. Our government "devolved" from yours.

I find multipath to be a more serious problem (compared to analog) with
many digital transmission formats. But, what do I know ... I don't work
for the government.


That's pretty much the feeling here too, Charles. When they originally
started foisting the 'digital TV revolution' on us, they ran TV adverts with
a well-known fat comedian and his knitted monkey puppet, to tell everyone
how they were going to be able to just buy a set-top box or digital TV set,
and jam it on the end of their existing UHF antenna. Well, of course, that
worked well, as you can imagine ...

Since then, the digital modulation format has changed in an effort to make
the signals more robust. Needless to say, not all existing STBs could cope
with the change in the number of carriers. It's now pretty much accepted
that in many areas of the country, in order to stand a cat's chance in hell
of receiving these transmissions, which are often contained in multiplexes
spread from one end of the band at 470 MHz to the other at around 820 MHz, a
serious antenna upgrade to a wideband ugly toast rack and new double
screened coax at a total cost of around £150 ( $280) is required. If you do
have trouble with multipath, which as you say, is not uncommon, then you can
be doubling those amounts.

Where I live, we have a clear line of site to the original analogue
transmitter about 20 miles away. We could receive perfect pictures on a
piece of wet string. Now, it needs a great big metal thing on the roof. Many
are either double stacked yagis, or the 'X' element "antighost" types. Now
the latest thing is the HD debate. Originally, the government and their
mouthpiece Ofcom (the supposedly politically independent broadcast
regulating body in the UK) said that when the analogue transmissions were
closed out, some of the additional bandspace won, would be used to allow
DTTV to carry HD broadcasts. Now, recently, they seem to have reneged on
this, and are now saying that no more space will be allocated, and a
different compression system will have to be employed, to win the necessary
space. This has gone down like a lead balloon with the manufacturers, who
have been selling "HD Ready" TV sets, based on the existing compression
scheme, for some time.

This makes it all quite clear that the whole thing is fundamentally a
government cash-raising exercise when they sell off the spectrum space for
billions to the mobile phone operators, glued on the back of a bunch of
flim-flam designed to make the public believe that they are somehow getting
a better deal than they had before.

Now that we have the same free digital transmissions available by
satellite - the new Freesat service - I can't see any point in the
terrestrial service, with all its bandwith and performance constraints,
continuing. But then, perhaps that's the intention ? Maybe I'm just being
cynical, but that would leave a 400 MHz swathe of bandspace, completely
available for sale ...

Arfa




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Default "tuning" in a Freeview digital TV set-top box

In article ,
Arfa Daily wrote:
Where I live, we have a clear line of site to the original analogue
transmitter about 20 miles away. We could receive perfect pictures on a
piece of wet string. Now, it needs a great big metal thing on the roof.
Many are either double stacked yagis, or the 'X' element "antighost"
types.


That really doesn't make sense to me.

However, the ERP of the digital services will be upped when the analogue
ones are switched off.

--
*Just remember...if the world didn't suck, we'd all fall off*

Dave Plowman London SW
To e-mail, change noise into sound.
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Default "tuning" in a Freeview digital TV set-top box

Charles wrote in message
. ..


"Arfa Daily" wrote in message
...

"Charles" wrote in message
. ..


Multipath?


Well, of course Charles, we all know in the UK that digital doesn't

suffer
from multipath. In fact it's immune from everything ! The government

says
so ... d;~}


Sigh. Our government "devolved" from yours.

I find multipath to be a more serious problem (compared to analog) with

many
digital transmission formats. But, what do I know ... I don't work for

the
government.



Could a multipath problem "knotch" out one specific frequency for all times
of day and weather conditions. I think of it more with wavering effects that
come and go with moving metalwork or weather/time variation.




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Default "tuning" in a Freeview digital TV set-top box


"Dave Plowman (News)" wrote in message
...
In article ,
Arfa Daily wrote:
Where I live, we have a clear line of site to the original analogue
transmitter about 20 miles away. We could receive perfect pictures on a
piece of wet string. Now, it needs a great big metal thing on the roof.
Many are either double stacked yagis, or the 'X' element "antighost"
types.


That really doesn't make sense to me.

However, the ERP of the digital services will be upped when the analogue
ones are switched off.

--
*Just remember...if the world didn't suck, we'd all fall off*

Dave Plowman London SW
To e-mail, change noise into sound.


Nor me really. I haven't bothered with equipping the house with DTTV, as I
can get all the services I need via Sky, so I haven't looked into why these
monster antennas seem to be needed. Of course, there's no reason why an
antighost antenna shouldn't work just as well without any ghosting problem
to overcome, so perhaps riggers are just carrying one type of 'catch-all'
antenna on their vans ? I know that in the nearby town, there have been many
issues with receiving reliable DTTV signals, so that might go along with my
suspicion.

I suppose another possibility could be to do with the reduced ERPs of the
digital transmitters, and also that not all of the DTTV transmitters are
co-located with their analogue counterparts. Maybe where I am, that is the
case, and in the direction that the DTTV transmitter lies, there is in fact
some obstruction or adverse lie of the land. I'll have to have a bit closer
look to see if the toast racks are pointing in the same direction as the
discrete little 10 ele yagis on the houses that are still thusways equipped.

Arfa


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Default "tuning" in a Freeview digital TV set-top box

On Sep 14, 3:35*am, "Arfa Daily" wrote:

A different position for the aerial can make all the difference. Many years
ago, in the early UHF colour days, I was installing a TV in a village that
was a very difficult reception area, being in a complete hollow in the
countryside. We arranged for the aerial man to be there at the same time as
us. I clearly remember him walking backwards and forwards along the house's
ridge line, with an aerial 6 foot long on a 10 foot pole in his arms looking
for somewhere to get a signal. Success was the difference between a chimney
stack on one end of the house, and another one thirty feet away at the other
end ...


Hah, reminds me of the neighbor behind my summer cabin on the fringes
of Flagstaff AZ. This area is served by 8 or 9 repeater stations
carrying signals from the Phoenix channels. Repeater stations in the
colonies, incidentally, are not required at this time to switch over
to digital - most of the repeaters that we can receive at our cabin
are staying analog for the near future.

Anyway, the neighbor is the chief engineer for one of the Phoenix
stations, stands to reason he has the best TV reception in the area.
When I asked him what he did to get such good reception, he mentioned
the type of antenna, the type of coax, and the fact that he borrowed a
portable spectrum analyzer from work and walked his roof until he
found the best possible signal.

Jerry
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Default "tuning" in a Freeview digital TV set-top box


"Jerry" wrote in message
...
On Sep 14, 3:35 am, "Arfa Daily" wrote:

A different position for the aerial can make all the difference. Many
years
ago, in the early UHF colour days, I was installing a TV in a village that
was a very difficult reception area, being in a complete hollow in the
countryside. We arranged for the aerial man to be there at the same time
as
us. I clearly remember him walking backwards and forwards along the
house's
ridge line, with an aerial 6 foot long on a 10 foot pole in his arms
looking
for somewhere to get a signal. Success was the difference between a
chimney
stack on one end of the house, and another one thirty feet away at the
other
end ...


Hah, reminds me of the neighbor behind my summer cabin on the fringes
of Flagstaff AZ. This area is served by 8 or 9 repeater stations
carrying signals from the Phoenix channels. Repeater stations in the
colonies, incidentally, are not required at this time to switch over
to digital - most of the repeaters that we can receive at our cabin
are staying analog for the near future.

Anyway, the neighbor is the chief engineer for one of the Phoenix
stations, stands to reason he has the best TV reception in the area.
When I asked him what he did to get such good reception, he mentioned
the type of antenna, the type of coax, and the fact that he borrowed a
portable spectrum analyzer from work and walked his roof until he
found the best possible signal.

Jerry

There ya go then ! Identical story from 4000 miles away !

Arfa




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Default "tuning" in a Freeview digital TV set-top box

www.maplin.co.uk
Freeview crap.
cuhulin

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