attenuator
 

I think that I need an attenuator for my DTV (set top box) receiver. I have
a four way splitter on the aerial and on three of the longest cable runs
all works OK. On the shortest cable run the picture is distorted. If I
create a 'poor' aerial connection on this short run the picture improves. As
you can see I know little about aerial systems and would be grateful if
anyone could advise me on a suitable variable attenuator I could try.
Obviously I cannot turn down the power on the splitter as then the longer
runs would be degraded. Many thanks.

Peter

attenuator
 

wrote in message
...
I think that I need an attenuator for my DTV (set top box) receiver. I have
a four way splitter on the aerial and on three of the longest cable runs
all works OK. On the shortest cable run the picture is distorted. If I
create a 'poor' aerial connection on this short run the picture improves.
As you can see I know little about aerial systems and would be grateful if
anyone could advise me on a suitable variable attenuator I could try.
Obviously I cannot turn down the power on the splitter as then the longer
runs would be degraded. Many thanks.

So we can gauge the liklihood of this really being signal overload, could
you tell us the transmitter and your distance from it, and whether the
aerial is in the loft? Could you describe the 'distorted' picture? It seems
very surprising if a normal DDT box is being overloaded by a signal that has
been attenuated by 8dB in a splitter. Have you tried swapping the DTT boxes
around? You could have a faulty one that cannot automatically adjust its
sensitivity.

For variable attenuators, have a look at CPC (Google it). You might be
better to buy 6dB and 12dB fixed ones though. These are in the CPC catalogue
as well.

Bill

attenuator
 

On Sep 24, 10:57*am, "Bill Wright"
wrote:
wrote in message

...

I think that I need an attenuator for my DTV (set top box) receiver. I have
a four way splitter on *the aerial and on three of the longest cable runs
all works OK. On the shortest cable run the picture is distorted. If I
create a 'poor' aerial connection on this short run the picture improves..
As you can see I know little about aerial systems and would be grateful if
anyone could advise me on a suitable variable attenuator I could try.
Obviously I cannot turn down the power on *the splitter as then the longer
runs would be degraded. Many thanks.

So we can gauge the liklihood of this really being signal overload, could
you tell us the transmitter and your distance from it, and whether the
aerial is in the loft? Could you describe the 'distorted' picture? It seems
very surprising if a normal DDT box is being overloaded by a signal that has
been attenuated by 8dB in a splitter. Have you tried swapping the DTT boxes
around? You could have a faulty one that cannot automatically adjust its
sensitivity.

For variable attenuators, have a look at CPC (Google it). You might be
better to buy 6dB and 12dB fixed ones though. These are in the CPC catalogue
as well.

Bill

I just happened to be looking at these myself so as my good deed for
the day
http://cpc.farnell.com/attenuators
That being complete I can now return to being a miserable old sod :D

attenuator
 

Bill Wright wrote:
wrote in message
...
I think that I need an attenuator for my DTV (set top box) receiver. I have
a four way splitter on the aerial and on three of the longest cable runs
all works OK. On the shortest cable run the picture is distorted. If I
create a 'poor' aerial connection on this short run the picture improves.
As you can see I know little about aerial systems and would be grateful if
anyone could advise me on a suitable variable attenuator I could try.
Obviously I cannot turn down the power on the splitter as then the longer
runs would be degraded. Many thanks.

So we can gauge the liklihood of this really being signal overload, could
you tell us the transmitter and your distance from it, and whether the
aerial is in the loft? Could you describe the 'distorted' picture? It seems
very surprising if a normal DDT box is being overloaded by a signal that has
been attenuated by 8dB in a splitter. Have you tried swapping the DTT boxes

I think you missed the "turn down the power in the splitter", Bill :-)

around? You could have a faulty one that cannot automatically adjust its
sensitivity.

For variable attenuators, have a look at CPC (Google it). You might be
better to buy 6dB and 12dB fixed ones though. These are in the CPC catalogue
as well.

Bill



--
PeeGee

"Nothing should be able to load itself onto a computer without the
knowledge or consent of the computer user. Software should also be able
to be removed from a computer easily."
Peter Cullen, Microsoft Chief Privacy Strategist (Computing 18 Aug 05)

attenuator
 

I think you missed the "turn down the power in the splitter", Bill :-)

around? You could have a faulty one that cannot automatically adjust its
sensitivity.

For variable attenuators, have a look at CPC (Google it). You might be
better to buy 6dB and 12dB fixed ones though. These are in the CPC
catalogue
as well.

Bill



--
PeeGee

Caradon Hill is my transmitter about 15 miles away in line of sight. I have
a loft aerial. Turned down the power on the splitter and it now works OK.
Amplifier on splitter is adjustable 0 - 20Db. Does this mean that the
signal was in fact too strong? I will have to see if other TVs on longer
cables will still function OK. Many thanks for the inputs.

Peter

attenuator
 

Obviously I cannot turn down the power on the splitter as then the longer
runs would be degraded. Many thanks.


That is not necessarily 'obvious' to me, have you tried that?
What are the approximate length of these runs?
Don't discount the possibility that the Rx on the end
of the long cable run may be intrinsically less accommodating
of a strong signals, in spite of the extra cable losses.
By the way I (we) presume by "distorted picture" you are referring
to freezing / pixilation and not poor colour etc.

--
Graham.

%Profound_observation%

attenuator
 

"Bill Wright" wrote in message
...

wrote in message
...
I think that I need an attenuator for my DTV (set top box) receiver. I
have a four way splitter on the aerial and on three of the longest cable
runs all works OK. On the shortest cable run the picture is distorted. If
I create a 'poor' aerial connection on this short run the picture
improves. As you can see I know little about aerial systems and would be
grateful if anyone could advise me on a suitable variable attenuator I
could try. Obviously I cannot turn down the power on the splitter as then
the longer runs would be degraded. Many thanks.

So we can gauge the liklihood of this really being signal overload, could
you tell us the transmitter and your distance from it, and whether the
aerial is in the loft? Could you describe the 'distorted' picture? It
seems very surprising if a normal DDT box is being overloaded by a signal
that has been attenuated by 8dB in a splitter.

You appear to misunderstand how a splitter works. A 4way splitter does
NOT reduce the signal by 8dB on each outlet. I have never known one
to decrease a signal by as much as 6 times if you look at the log scale.

Have you tried swapping the DTT boxes around? You could have a faulty one
that cannot automatically adjust its sensitivity.


It wouldn't work correctly if it couldn't! It would tend to show no signal
rather than a distorted or broken one.

For variable attenuators, have a look at CPC (Google it). You might be
better to buy 6dB and 12dB fixed ones though. These are in the CPC
catalogue as well.

Bill

Bad advice through lack of unerstanding of RF systems! No wonder you
spend so much time slagging off other peoples work you claim to correct
but refuse to name for fear of legal action!

attenuator
 

"Roger" wrote in message
...

"Bill Wright" wrote in message
...

wrote in message
...
I think that I need an attenuator for my DTV (set top box) receiver. I
have a four way splitter on the aerial and on three of the longest cable
runs all works OK. On the shortest cable run the picture is distorted. If
I create a 'poor' aerial connection on this short run the picture
improves. As you can see I know little about aerial systems and would be
grateful if anyone could advise me on a suitable variable attenuator I
could try. Obviously I cannot turn down the power on the splitter as
then the longer runs would be degraded. Many thanks.

So we can gauge the liklihood of this really being signal overload, could
you tell us the transmitter and your distance from it, and whether the
aerial is in the loft? Could you describe the 'distorted' picture? It
seems very surprising if a normal DDT box is being overloaded by a signal
that has been attenuated by 8dB in a splitter.

You appear to misunderstand how a splitter works. A 4way splitter does
NOT reduce the signal by 8dB on each outlet. I have never known one
to decrease a signal by as much as 6 times if you look at the log scale.

Have you tried swapping the DTT boxes around? You could have a faulty one
that cannot automatically adjust its sensitivity.


It wouldn't work correctly if it couldn't! It would tend to show no
signal
rather than a distorted or broken one.

For variable attenuators, have a look at CPC (Google it). You might be
better to buy 6dB and 12dB fixed ones though. These are in the CPC
catalogue as well.

Bill

Bad advice through lack of unerstanding of RF systems! No wonder you
spend so much time slagging off other peoples work you claim to correct
but refuse to name for fear of legal action!

Peter, as you may be new here some introductions may be helpful
although I suspect you will have deduced as much for yourself:

Meet Bill, much respected and regular contributor to this group,
and Roger, the village idiot.


--
Graham.

%Profound_observation%

attenuator
 

In message , Roger
writes


You appear to misunderstand how a splitter works. A 4way splitter does
NOT reduce the signal by 8dB on each outlet.

Nonsense. With a 2-way splitter, the typical loss is 3.5dB at low
frequencies, rising to nearly 3.8 to 4dB around 860Mhz. Double these
figures for a 4-way.

I have never known one
to decrease a signal by as much as 6 times if you look at the log scale.

I'm not sure that I (or you) understand that statement!
--
Ian

attenuator
 

"PeeGee" wrote in message
o.uk...
Bill Wright wrote:
wrote in message
...
I think that I need an attenuator for my DTV (set top box) receiver. I
have
a four way splitter on the aerial and on three of the longest cable
runs
all works OK. On the shortest cable run the picture is distorted. If I
create a 'poor' aerial connection on this short run the picture
improves.
As you can see I know little about aerial systems and would be grateful
if
anyone could advise me on a suitable variable attenuator I could try.
Obviously I cannot turn down the power on the splitter as then the
longer
runs would be degraded. Many thanks.

So we can gauge the liklihood of this really being signal overload, could
you tell us the transmitter and your distance from it, and whether the
aerial is in the loft? Could you describe the 'distorted' picture? It
seems
very surprising if a normal DDT box is being overloaded by a signal that
has
been attenuated by 8dB in a splitter. Have you tried swapping the DTT
boxes

I think you missed the "turn down the power in the splitter", Bill :-)

I did indeed. Actually, because a splitter is a splitter, I subconsciously
ignored it.

Bill