Angus transmitter advice please

I am trying to get a decent DTT service with a loft aerial in my son's
new house. I have installed an Antiference XG10 of the right group
(C/D) with a masthead amp powered from a Labgear distribution amp.
Using a laptop with tuner that shows signal strength and errors I can
get an acceptable picture on all Muxes except for A (Channel 5). Here
the strength seems OK but the BER is not and the picture breaks up. Do
all Muxes get transmitted at the same strength or am I missing
something somewhere?

"ChrisW" wrote in message
...
I am trying to get a decent DTT service with a loft aerial in my son's
new house. I have installed an Antiference XG10 of the right group
(C/D) with a masthead amp powered from a Labgear distribution amp.
Using a laptop with tuner that shows signal strength and errors I can
get an acceptable picture on all Muxes except for A (Channel 5). Here
the strength seems OK but the BER is not and the picture breaks up. Do
all Muxes get transmitted at the same strength or am I missing
something somewhere?

I do not know exactly what you are saying (BER) but we are in Monifieth and
receive all digital channels ok inc Ch5.

On Sep 1, 7:20 pm, ChrisW wrote:
I can
get an acceptable picture on all Muxes except for A (Channel 5). Here
the strength seems OK but the BER is not and the picture breaks up. Do
all Muxes get transmitted at the same strength or am I missing
something somewhere?

Ah yes, well, probably.
In the absence of the experts, from what I've seen on various
newsgroups, this is a common problem.
The listings show all muxes from Angus at the same power.
However, muxes 2 and A are using mode 64 QAM 2/3, while the others use
16 QAM 3/4.
64 QAM appears to be a less robust transmission mode, but it allows
more channels to be squeezed in.
This is probable the root of your problem, however all should be cured
on switchover, when the powers are increased.
VB.

"Gio" wrote in message ...

"ChrisW" wrote in message
...
I am trying to get a decent DTT service with a loft aerial in my son's
new house. I have installed an Antiference XG10 of the right group
(C/D) with a masthead amp powered from a Labgear distribution amp.
Using a laptop with tuner that shows signal strength and errors I can
get an acceptable picture on all Muxes except for A (Channel 5). Here
the strength seems OK but the BER is not and the picture breaks up. Do
all Muxes get transmitted at the same strength or am I missing
something somewhere?

I do not know exactly what you are saying (BER) but we are in Monifieth
and receive all digital channels ok inc Ch5.

Bit error rate, a measure of signal quality.

--
Graham.
%Profound_observation%

"Graham." wrote in message
...


I do not know exactly what you are saying (BER) but we are in Monifieth
and receive all digital channels ok inc Ch5.

Bit error rate, a measure of signal quality.

--
Graham.


Thank you.

Gio

"Graham." wrote in message
...
Bit error rate, a measure of signal quality.

Posh people say 'ratio'.

Bill

On Sat, 01 Sep 2007 19:20:12 +0100, ChrisW
wrote:

I am trying to get a decent DTT service with a loft aerial in my son's
new house. I have installed an Antiference XG10 of the right group
(C/D) with a masthead amp powered from a Labgear distribution amp.
Using a laptop with tuner that shows signal strength and errors I can
get an acceptable picture on all Muxes except for A (Channel 5). Here
the strength seems OK but the BER is not and the picture breaks up. Do
all Muxes get transmitted at the same strength or am I missing
something somewhere?

Have a look at http://www.dtg.org.uk/retailer/tx_cscot.html for the
channels and power etc. As has been said this mux uses 64QAM which is
less robust than 16 QAM, but so does mux2 and you can decode that ok.
Depending on the level of your received signal and the gain of your
masthead amp you could be overloading the masthead amp or STB. Try it
without the MHA, or fit an attenuator before the MHA and set what
happens. If that makes no difference try adjusting the aerial to
optimise the BER on mux A only and see what happens. Depending on
these results you might need to move the aerial outside. Also worth
checking with neighbours what their DTT pictures are like.

--
Bryce Whiteford

wrote:

I am trying to get a decent DTT service with a loft aerial in my son's
new house. I have installed an Antiference XG10 of the right group
(C/D) with a masthead amp powered from a Labgear distribution amp.
Using a laptop with tuner that shows signal strength and errors I can
get an acceptable picture on all Muxes except for A (Channel 5). Here
the strength seems OK but the BER is not and the picture breaks up. Do
all Muxes get transmitted at the same strength or am I missing
something somewhere?

Other have given specific reasons for the loss of one mux, but in general
loft aerials are a compromise. It's in the nature of RF that inequalities
will develop between different frequencies along the path from TX to Rx, and
it's often a waste of time trying to determine the cause. Any solution that
you find in the loft is likely to be only marginally above threshold. If you
want a simple foolproof reliable solution you should put the aerial outside.
In the end it will be less trouble and better.

In the world of commercial rigging this translates as "Do you want to pay me
to muck about for ages in the loft just to find a shakey solution, or do you
want to pay me less to put the aerial outside where the results will be
guaranteeable?"

Bill