Dumb question: aerial connections to TV

On 30/09/2018 19:14, R. Mark Clayton wrote:

Maplins? Didn't they go bust.


Yes that's why they were in inverted comma's - not sure where you would go now

CPC

Bill

On 30/09/2018 18:31, Davey wrote:

Here, I am within a few miles of Tacolneston, and I can drive two PVRs
and a TV set using only splitters. I have a booster available if I need
it, but so far, it just sits in a box.


Signal here from Emley Moor, 16 miles away on a log periodic aerial: 18dBmV
Loss on an eight way inductive splitter is 12dB so we have eight feeds
at 6dBmV.
Loss on each of eight eight-way splitters is 12dB so we have 64 feeds at
-6dBmV.
Loss on each of 64 six-way splitters is 10dB so we have 384 feeds at
-16dBmV. Cable loss is 3dB so I have 384 feeds at -19dB. That signal
level is low but will work perfectly, especially as it is a very clean
signal. Why so clean I hear you chorus? Because (1) it is derived from
an aerial that's receiving such a strong signal that local noise, CCI,
etc is insignificant, and (2) there is no amplification (which would add
noise).
We only have 383 TV sets so there is one spare feed.

Bill

On Sun, 30 Sep 2018 17:58:46 +0100, Yellow
wrote:

In article ,
says...

On Sunday, 30 September 2018 14:56:39 UTC+1, Yellow wrote:
In article , lalaw44
@hotmail.com says...

Sorry for interrupting this august body with a question so simple but ...

Our TV (Sony Bravia) gets its aerial feed via the PVR (Humax Fox T2).

Owing to its continuing Green Screen problems, the Humax is frequently
powered off (via the switch on the back of the box).

The TV picture then degrades, until lost completely, so we have to
switch the Humax back on.

My dumb question: why does the aerial need the power on, to connect
through to the TV?

Cheers chaps
John

Because the Humax contains a powered splitter so each device gets more
than half of the signal that comes from the aerial.

I had a similar problem with a satellite receiver.


The alternative is to run a separate aerial lead to your TV and Humax.
You can use a passive device if you have a strong enough signal or you
can buy a powered unit.

If the signal is good you can use a resistive splitter. ~-4.5dB £1 pound shop

Less good and you can use a reactive splitter. -3dB £4 "Maplins"

Maplins? Didn't they go bust.

Yes.
But Peter Jones (od Dragon's Den) has bought the name, etc, and is
planning to start Maplin as an online-only business.

https://www.theregister.co.uk/2018/0...en_maplins_ip/

https://www.maplin.co.uk/

We're back and will be celebrating our website relaunch very soon!
GET 10% OFF YOUR FIRST ORDER




Less good still and you can use a switch ~-0.3dB. £2. TV place.

Amp' unlikely to be required unless signal is marginal.


I have this one for example -

https://www.amazon.co.uk/Philex-Way-...dp/B00DB22ZTI/


--
Peter Duncanson
(in uk.tech.digital-tv)

On 30/09/2018 19:14, R. Mark Clayton wrote:

OTOH https://www.screwfix.com/p/labgear-2...pass-all-ports £4


That one has F connectors. For a standard aerial connection try this one
https://www.screwfix.com/p/labgear-1...splitter/44534

It has got reasonable reviews.

Jim

In article ,
says...

On Sunday, 30 September 2018 17:58:32 UTC+1, Yellow wrote:
In article ,
says...

On Sunday, 30 September 2018 14:56:39 UTC+1, Yellow wrote:
In article , lalaw44
@hotmail.com says...

Sorry for interrupting this august body with a question so simple but ...

Our TV (Sony Bravia) gets its aerial feed via the PVR (Humax Fox T2).

Owing to its continuing Green Screen problems, the Humax is frequently
powered off (via the switch on the back of the box).

The TV picture then degrades, until lost completely, so we have to
switch the Humax back on.

My dumb question: why does the aerial need the power on, to connect
through to the TV?

Cheers chaps
John

Because the Humax contains a powered splitter so each device gets more
than half of the signal that comes from the aerial.

I had a similar problem with a satellite receiver.


The alternative is to run a separate aerial lead to your TV and Humax.
You can use a passive device if you have a strong enough signal or you
can buy a powered unit.

If the signal is good you can use a resistive splitter. ~-4.5dB £1 pound shop

Less good and you can use a reactive splitter. -3dB £4 "Maplins"

Maplins? Didn't they go bust.


Yes that's why they were in inverted comma's - not sure where you would go now - local RS trade counter if they will serve you?

Ah, OK.

But because of your post I googled and got this!

https://www.maplin.co.uk/

But perhaps it is a joke?



OTOH https://www.screwfix.com/p/labgear-2...pass-all-ports £4



Less good still and you can use a switch ~-0.3dB. £2. TV place.

Amp' unlikely to be required unless signal is marginal.


I have this one for example -

https://www.amazon.co.uk/Philex-Way-...dp/B00DB22ZTI/

In article ,
says...

On Sun, 30 Sep 2018 17:58:46 +0100, Yellow
wrote:

In article ,
says...

On Sunday, 30 September 2018 14:56:39 UTC+1, Yellow wrote:
In article , lalaw44
@hotmail.com says...

Sorry for interrupting this august body with a question so simple but ...

Our TV (Sony Bravia) gets its aerial feed via the PVR (Humax Fox T2).

Owing to its continuing Green Screen problems, the Humax is frequently
powered off (via the switch on the back of the box).

The TV picture then degrades, until lost completely, so we have to
switch the Humax back on.

My dumb question: why does the aerial need the power on, to connect
through to the TV?

Cheers chaps
John

Because the Humax contains a powered splitter so each device gets more
than half of the signal that comes from the aerial.

I had a similar problem with a satellite receiver.


The alternative is to run a separate aerial lead to your TV and Humax.
You can use a passive device if you have a strong enough signal or you
can buy a powered unit.

If the signal is good you can use a resistive splitter. ~-4.5dB £1 pound shop

Less good and you can use a reactive splitter. -3dB £4 "Maplins"

Maplins? Didn't they go bust.

Yes.
But Peter Jones (od Dragon's Den) has bought the name, etc, and is
planning to start Maplin as an online-only business.

https://www.theregister.co.uk/2018/0...en_maplins_ip/

https://www.maplin.co.uk/

We're back and will be celebrating our website relaunch very soon!
GET 10% OFF YOUR FIRST ORDER


I found the website when I googled but was not aware of the story behind
it.

Thanks!

Because it obviously has an active splitter inside, to compensate for the
splitting of the signal. Most old videos did this as well, so its nothing
new. Personally in most cases unless you are using a modulator system, I see
no harm in putting in a passive splitter, with one lead going to the box
and the other to the set. This assumes you have enough signal, but if its
really that borderline, then I'd have thought the amp in the box might have
made it worse not better as it generates noise.
Brian

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"Another John" wrote in message
...
Sorry for interrupting this august body with a question so simple but ...

Our TV (Sony Bravia) gets its aerial feed via the PVR (Humax Fox T2).

Owing to its continuing Green Screen problems, the Humax is frequently
powered off (via the switch on the back of the box).

The TV picture then degrades, until lost completely, so we have to
switch the Humax back on.

My dumb question: why does the aerial need the power on, to connect
through to the TV?

Cheers chaps
John

Yes those inductive splitters seem pretty good to me, but if you have a pet,
make sure its not accessible, they like the plastic.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Bill Wright" wrote in message
news
On 30/09/2018 16:43, R. Mark Clayton wrote:

If the signal is good you can use a resistive splitter. ~-4.5dB £1 pound
shop

More like 5 to 8dB

Less good and you can use a reactive splitter. -3dB £4 "Maplins"

Inductive splitter. 4dB.

Less good still and you can use a switch ~-0.3dB. £2. TV place.

Switch losses can be 2dB. Daft to use a switch. Just gets left turned the
wrong way and you lose a recording.

Bill

On 01/10/2018 00:43, Brian Gaff wrote:
Yes those inductive splitters seem pretty good to me, but if you have a pet,
make sure its not accessible, they like the plastic.
Brian

The proper ones are in diecast housings so they are screened.

Bill

In article ,
Indy Jess John wrote:

On 30/09/2018 13:17, Another John wrote:
Sorry for interrupting this august body with a question so simple but ...

Our TV (Sony Bravia) gets its aerial feed via the PVR (Humax Fox T2).

Owing to its continuing Green Screen problems, the Humax is frequently
powered off (via the switch on the back of the box).

The TV picture then degrades, until lost completely, so we have to
switch the Humax back on.

My dumb question: why does the aerial need the power on, to connect
through to the TV?

Cheers chaps
John

The Humax takes the signal in, looks for the channels it knows about so
that it can warn you of new ones, then regenerates the aerial signal so
that it passes on to the TV. When working properly, the Humax will
slightly amplify the output signal so that the TV gets a slightly
stronger signal.

If you turn off the Humax power, it cannot regenerate the signal for the
TV so that the wire going into the TV goes dead. The Humax power supply
has a small reserve of power in its capacitors, which is why the picture
degrades before disappearing.

If you have a strong signal, you might get away with a 2-way splitter on
the aerial wire, one output going to the TV and the other to the Humax.
If you have a weaker signal, then a signal booster with 2 or more
output ports will allow you to connect one output to the TV and the
other to the Humax. Either solution will give you a signal to the TV
whether the Humax is on or off. What you won't be able to do is take
the Humax playback output as an RF channel down the aerial cable, but
you probably were not doing that anyway; the normal connection method
will be either HDMI or SCART.

OP he Jim -- that is a wonderful piece of user-oriented technical
writing! Thanks a lot!

All: I'm overwhelmed with getting so many expert answers so quickly!
The discussion has proved very instructive: thanks very much, everybody!

John