The journey to all Freeview channels
 

I have posted a few questions recently and received some useful advice
- thanks.

Here is a summary of the story so far and my latest step in the quest
for all Freeview channels.

I am about 25 miles south of Sutton Coldfield. My predicted reception
is muxes: 1, B and D. Or from Lark Stoke: 1, 2, A, B.

First I just bought a STB (actually a SBB - Set Beside Box). I
immediately got mux 1 well. All others (including C) would be
detected at least occasionally but were unwatcheable most of the time

Next I had the aerial upgraded. I retained 1 and gained B and C. D
would sometimes be detected but was worse. 2 and A vanished
altogether.

Finally I figured out a neat and easy way to replace the long and old
downfeed. The downfeed is now new and much shorter. This has
helped. All but mux 2 are now good most of the time. (Rain reduces
reception and heavy rain makes some muxes disappear). Sometimes I get
mux 2 but it is watcheable only occasionally.

This is quite good and has been worth the effort and the cost but it
is a bit puzzling. I still wonder why I get some muxes and not
others. Some of this has been explained by responses to my previous
notes but some puzzles remain. For example, prior to replacing the
downfeed I was missing 2 and A. I learnt that these were 64QAM and
hence may need a better signal. But now I have gained A but not 2.
Why might that be?

I toyed with trying to use LS as well as SC for a while but gave up
due to the complexity.

Any suggestions for gaining mux 2?

I am using an RF amplifier. It is an old one from Wickes, several
years older than digital terrestrial. It does help, removing it
worsens both digital and analogue considerably. I tried a new
amplifier from Maplin. I thought that being newer and boasting that
it was good for digital, it may be better than the old one. In fact,
it is worse, it seems to be no better than nothing and much worse than
the old one. Maplin did refund me. Can anyone recommend a good RF
amplifier? It needs to do VHF for FM as well.

The effect on analogue reception is also a bit of a puzzle. Prior to
this work, 1 and, 2 were good but not perfect. 3 was a bit poorer but
still OK 4 was bad and sometimes unwatcheable. 5 was excellent.
Since the work 1 and 2 are poorer but this is not too important since
they are quite good and reliable on digital. Analogue 4 is now good
which is fortunate since I don't get it on digital. 5 is still
excellent, hard to tell the difference between analogue and digital.
But 3 is much worse, worse than 4 before the work. And since 3 is on
mux 2, I cannot see it on analogue either.

This is not a disaster since we don't watch ITV much. If I had to
lose one analogue channel, this would be my choice. But it would
still be nice to get it back on analogue or digital or both. The
analogue is still has required for recording so the poorer 1 and 2 is
still relevant.

Any ideas on these analogue effects?

John

"Sean O'Leathlobhair" wrote in message

Finally I figured out a neat and easy way to replace the long and old
downfeed. The downfeed is now new and much shorter. This has
helped. All but mux 2 are now good most of the time. (Rain reduces
reception and heavy rain makes some muxes disappear). Sometimes I get
mux 2 but it is watcheable only occasionally.

This is quite good and has been worth the effort and the cost but it
is a bit puzzling. I still wonder why I get some muxes and not
others. Some of this has been explained by responses to my previous
notes but some puzzles remain. For example, prior to replacing the
downfeed I was missing 2 and A. I learnt that these were 64QAM and
hence may need a better signal. But now I have gained A but not 2.
Why might that be?

There's not much between them (44 47) so they shouldn't propagate that much
differently, however 2 sits right next to ITV analogue and may not be equalised
with the rest of the muxes for that reason, or Bad Things are happening by the
time it reaches you.

They really need +3dB at main sites, they can't be putting people to so much
trouble at 25 miles, it's hardly the moon and back and doesn't replicate
analogue coverage, or reliability.

Did they fit you a grouped aerial or a wideband jobby? You need every bit of
gain possible, a masthead amp might be worth a try.

Az.

"Aztech" wrote in message ...
"Sean O'Leathlobhair" wrote in message

Finally I figured out a neat and easy way to replace the long and old
downfeed. The downfeed is now new and much shorter. This has
helped. All but mux 2 are now good most of the time. (Rain reduces
reception and heavy rain makes some muxes disappear). Sometimes I get
mux 2 but it is watcheable only occasionally.

This is quite good and has been worth the effort and the cost but it
is a bit puzzling. I still wonder why I get some muxes and not
others. Some of this has been explained by responses to my previous
notes but some puzzles remain. For example, prior to replacing the
downfeed I was missing 2 and A. I learnt that these were 64QAM and
hence may need a better signal. But now I have gained A but not 2.
Why might that be?

There's not much between them (44 47) so they shouldn't propagate that much
differently, however 2 sits right next to ITV analogue and may not be equalised
with the rest of the muxes for that reason, or Bad Things are happening by the
time it reaches you.

They really need +3dB at main sites, they can't be putting people to so much
trouble at 25 miles, it's hardly the moon and back and doesn't replicate
analogue coverage, or reliability.

Did they fit you a grouped aerial or a wideband jobby? You need every bit of
gain possible, a masthead amp might be worth a try.

Az.

I have managed a further improvement. Now I get all stations well
most of the time. The ITV mux is still the poorest but now it is
acceptable most of the time rather than just some of the time. The
others are fine almost always.

At the time of writing, I was still using a test version of the final
set-up. The downfeed was going across the roof, through a window and
into the bedroom. This has now been made permanent with the cable
going through a new hole in the wall, along the loft space and down to
the RF amplifier. I did not expect that this last chance would make
much difference (except for looking nicer) but it has. The
improvement is 20m of cable down to 4m. Also when joining the wires,
the aerial man recommended just twisting them together and taping
rather than using terminal strip as I did in the temporary set-up.

This seems to show the length of the cable is very important. The
test cable and the final cable were both new (in fact the very same
cable but cut). Unless the terminal strip was a major problem, losing
that 16m made a big difference.

The downstairs TV is a bit poorer but OK. The ITV mux breaks up a bit
more often. The STBs are different so that could be the explanation
but the last time I swapped them, I could see no difference. I will
swap them again when I get the time. Again there is a cable length
issue, this time after the RF amplifier. The upstairs STB has a
typical short patch cable from the amplifier, downstairs has about 6m
of cable.

There is one last thing to try if I feel the need. If I was prepared
to run mains into the loft, I could place the RF amplifier with only a
couple of metres of cable between it and the aerial. The total length
between the aerial and the STB would be the same but the amplifier
would be nearer the aerial. Is that worth trying?

Seán O'Leathlóbhair

There is one last thing to try if I feel the need. If I was prepared
to run mains into the loft, I could place the RF amplifier with only a
couple of metres of cable between it and the aerial. The total length
between the aerial and the STB would be the same but the amplifier
would be nearer the aerial. Is that worth trying?

Yes. But why not use a line powered masthead amp?

Bill
--

Lots of aerial bits and pieces on ebay. See seller name tvaerialguy

SNIP
.. . Also when joining the wires,
the aerial man recommended just twisting them together and taping
rather than using terminal strip as I did in the temporary set-up.


SNIP

Were these coax wires??? IF so ALWAY ALWAYS use a correct connector, get a
couple of F plugs and and a back to back F socket and then cover the whole
job in self amalgamating tape!!!

"James Salisbury" wrote in message ...
SNIP
. . Also when joining the wires,
the aerial man recommended just twisting them together and taping
rather than using terminal strip as I did in the temporary set-up.


SNIP

Were these coax wires??? IF so ALWAY ALWAYS use a correct connector, get a
couple of F plugs and and a back to back F socket and then cover the whole
job in self amalgamating tape!!!

Thanks for the tip.

I did this in a previous set-up and the effect seemed to be worse than
my next effort which was terminal strip. However, the plugs and the
back-to-back socket were cheap and nasty things from Wickes. I will
try and find some better quality ones. I notice that some coax plugs
have a screw to clamp the signal wire and others don't. Is that good?

A plug set-up would be good for another reason. I could then easily
experiment with the effect of shifting the RF amp to the loft and
getting it nearer to the aerial.

At least this is now in the loft so I do not need to climb up on the
roof.

Seán O'Leathlóbhair

I did this in a previous set-up and the effect seemed to be worse than
my next effort which was terminal strip. However, the plugs and the
back-to-back socket were cheap and nasty things from Wickes. I will
try and find some better quality ones. I notice that some coax plugs
have a screw to clamp the signal wire and others don't. Is that good?
You could have accidently shorted the inner core with the braid and that
will kill the signal. You need to remeber at TV and Radio frequencies the
signal travels as if it is in a pipe of certian dimentions, any distortions
can reflect the signal and cause other problems. To minimise the signal
loss, F type plugs are prefered, the center pin is the core of the coax. If
not then solder the pin in the standard TV plug, some are badly designed and
the screw shorts the connector, takeing care not to set fire to your loft!!!

What type of coax are you useing, does it have a light weave of copper as a
screen, or a thick braid and a foil as well?

How does the coax get from the loft to the telly, and how many tellys do you
have connected to the one ariel?



A plug set-up would be good for another reason. I could then easily
experiment with the effect of shifting the RF amp to the loft and
getting it nearer to the aerial.

At least this is now in the loft so I do not need to climb up on the
roof.

Seán O'Leathlóbhair

"Sean O'Leathlobhair" wrote in message
Also when joining the wires,
the aerial man recommended just twisting them together and taping
rather than using terminal strip as I did in the temporary set-up.

*gulp*

Try a direct run, joints are nasty.

Az.

You are deluged with information, but I would just add:
If you can fit a low gain (12dB) masthead amp at the bottom of the mast it
would be a good thing. Generally this will feed a distribution amp without
problems, but it just could result in too much gain overall weird pattening
etc), in which case you need to attenuate between the two amps. If you can get
mains to the masthead amp position you are as well to use a mains powered
'setback' amp, as long as it is a good quality one. The cheapys are noisy
(snowy pictures). If you increase signal levels by improving amplification the
splitter problems at the bottom will be cured.

Bill
--

Lots of aerial bits and pieces on ebay. See seller name tvaerialguy