Strange Happenings on Retuning a Digi Box
 

r brooks wrote:

Ian thanks. Two questions: What function does the use of a splitter serve,
I understand it weakens the incoming signal but what is the purpose of that
please?

The idea is to weaken the signals so that the weaker set (from the
'wrong' transmitter) are too weak to be stored. Meanwhile the stronger
ones remain strong enough to be stored.


If I get a variable attenuator from b and q, what kind of adjustment would I
want to be making with it? Thanks.

Trial and error until you achieve the above. Start at the max atten end.

Bill

Strange Happenings on Retuning a Digi Box
 

In article ,
says...

On 10/01/2014 22:04, r brooks wrote:
Grateful for any advice on my situation with a Digi Box, when i've just done
a *factory-default* on a Humax HDR Fox T2, which I did because i was missing
some TV channels.

I'm located in Finchley North London near a Relay Station, but my main
transmitter is Crystal Palace.

When i did my factory default the BBC TV programs were rubbish (picture
breaking up). I remembered some advice to use a 'splitter' to reduce the
signal strength for some reason when doing the re-tune.

After re-tuning using the splitter the BBC stations as well as all the other
stations seem to work OK. But I now get some HD stations in the channels
numbered in the 800s' as well as the 100s. The HD channels in the 100s
work ok, but all the HD channels in the 800s are still breaking up.

Grateful for any advice on what I might usefully do further. Thanks

Your aerial is picking up signals from two different transmitters.

When this happens Humax non YouView boxes replicate channels by placing
them in the location you have cited.

There is a solution but one way is to have your aerial realigned.

The answer is simple - decide which transmitter you want to use and then
go to this website to identify the channel numbers used by that
transmitter. Write them down and keep the piece of paper safe for next
time.

http://www.digitaluk.co.uk/

Enter your postcode, house number and make sure you tick the box next to
the detailed view option.

Now, reset all the channels and do an individual manual tune for each of
the channel numbers identified.

If you can receive channels from more than one transmitter (my aerial
can see four of the possible six) it is the only reliable way and given
it is painless and easy to do, there is no reason not to.

Strange Happenings on Retuning a Digi Box
 

Gareth Davies wrote:

There is a solution but one way is to have your aerial realigned.


Because of the extreme sensitivity of many modern DTT receivers this is
unlikely to help, unless the aerial was grossly wrong in the first place.

Bill

Strange Happenings on Retuning a Digi Box
 

Ian Jackson wrote:

An obvious problem with the above is if the unwanted signals are
stronger than the wanted ones. This might be the case if you want to
receive the full complement of TV channels from the main transmitter,
but a stronger local relay transmitter is offering a reduced number of
channels (as many do).

Much depends on the receiver. Does is simply chose by signal strength or
does it chose by signal quality?

Bill

Strange Happenings on Retuning a Digi Box
 

In article , Bill Wright
scribeth thus
Ian Jackson wrote:

If you have to do an automatic tune, rather than use a splitter, a 20db
variable attenuator will give you better control of the signal level. I
was in B&Q yesterday, and I saw they do one (£7?) - which, if you need
one quickly, might be more convenient than getting one elsewhere online.

Or the free option, a loosely coupled pair of faraday loops (if that's
the proper name for them).

Bill

Well hats a nice idea:)..

And cheap too!....

--
Tony Sayer

Strange Happenings on Retuning a Digi Box
 

tony sayer wrote:

Or the free option, a loosely coupled pair of faraday loops (if that's
the proper name for them).

Bill

Well hats a nice idea:)..

And cheap too!....


When I was rigging for DER they wouldn't pay for attenuators, and the
sets of the time needed one when in Ponty and Barnsley. So I made loops.
My old German mentor showed me the trick, when I was a kid. Did I ever
mention Hans? He was in the Hitler Youth as a lad, and then in 1945 him
and his family lived in a sewer for months. He came to the UK on holiday
in the late 40s and stayed. A good immigrant.

Bill

Strange Happenings on Retuning a Digi Box
 

"Bill Wright" wrote in message
...
Gareth Davies wrote:

There is a solution but one way is to have your aerial realigned.


Because of the extreme sensitivity of many modern DTT receivers this is
unlikely to help, unless the aerial was grossly wrong in the first place.

Bill

-----------------------------------------------------------------------------------------

Conclusion:

Bought a variable attenuator on line for £3.15 inc postage. screwed it out
for maximum resistance (less one complete turn out of five turns) and it
eliminated all channels in the 800 range on the factory default/automatic
retune.

Many thanks to all for helping me get good results.

Strange Happenings on Retuning a Digi Box
 

In message , r brooks
writes

"Bill Wright" wrote in message
...
Gareth Davies wrote:

There is a solution but one way is to have your aerial realigned.


Because of the extreme sensitivity of many modern DTT receivers this is
unlikely to help, unless the aerial was grossly wrong in the first place.

Bill

------------------------------------------------------------------------
-----------------

Conclusion:

Bought a variable attenuator on line for £3.15 inc postage. screwed it out
for maximum resistance (less one complete turn out of five turns) and it
eliminated all channels in the 800 range on the factory default/automatic
retune.

Many thanks to all for helping me get good results.

Good conclusion. You can take it out until you do another scan.
--
Ian

Strange Happenings on Retuning a Digi Box
 

r brooks wrote:
"Bill Wright" wrote in message
...
Gareth Davies wrote:

There is a solution but one way is to have your aerial realigned.

Because of the extreme sensitivity of many modern DTT receivers this is
unlikely to help, unless the aerial was grossly wrong in the first place.

Bill

-----------------------------------------------------------------------------------------

Conclusion:

Bought a variable attenuator on line for £3.15 inc postage. screwed it out
for maximum resistance (less one complete turn out of five turns) and it
eliminated all channels in the 800 range on the factory default/automatic
retune.

Many thanks to all for helping me get good results.

For maximum reliability of the wanted signals try again with less
attenuation, and again and again, until the unwanted signals reappear,
then go back a step or two.

Bill

Strange Happenings on Retuning a Digi Box
 

Ian Jackson wrote:
In message , r brooks
writes

"Bill Wright" wrote in message
...
Gareth Davies wrote:

There is a solution but one way is to have your aerial realigned.


Because of the extreme sensitivity of many modern DTT receivers this is
unlikely to help, unless the aerial was grossly wrong in the first
place.

Bill

------------------------------------------------------------------------
-----------------

Conclusion:

Bought a variable attenuator on line for £3.15 inc postage. screwed it
out
for maximum resistance (less one complete turn out of five turns) and it
eliminated all channels in the 800 range on the factory default/automatic
retune.

Many thanks to all for helping me get good results.

Good conclusion. You can take it out until you do another scan.

I usually leave it in as long as long as the wanted channels are plenty
strong enough. People forget to use it when they do a retune, and it
could help with 4G (etc) problems.

Bill