Variable Digital reception

[IJWS15]

We have an external aerial pointed at Sutton Coldfield, amplifier in loft (been there since we moved in six years ago) with three outputs. All installation likely to be around 8 years old - pre digital.

A few months ago the signal got worse on some digital channes, but not others

e.g. BBC1-4 are fine, ITV 1&2 are fine, ITV4 is unwatchable, 19 is fine, until recently but 25 was no reception. Many others are no reception but 38 is fine.

Now this may be related to work on Sutton Coldfield but what puzzles me is why some channels are fine and some are terrible, and why did 25 go from terrible to fine about a week ago?

Wolfbane says I need an "Amplified extra hi-gain" aerial - the one we have looks like this (what are the elements? - not sure how they get to 48!)

Not sure what the booster is but it is at least 6 years old.

What can I do to improve the reception ? Should I replace the booster with one designed for digital? or is there anything else I can do? -

Don't particularly want to start replacing cables.

 

[ericmark]

There is no such thing as digital aerial or pre-amplifier however since digital many areas do need wider band aerials than before.

There are a few things that can effect signal one is power of transmitter and these have not been finalised yet and you may find they turn up power once other transmitters have been turned off.

One problem specially where fringe areas is interference which includes Sky boxes, VCR's etc.

The aerial has a gain and the more directors the higher the gain but also wide band aerials are bigger than narrow band and cross polarisation ones are also bigger. Although the Yargi Beam is the most popular it is not the only option and to work out gain by counting elements is only approximate.

UHF reception can be affected by loads of strange things. I know one guy who bounced his signals off a CB aerial up the hill from him and as a result pointing in right direction may not be as good as aiming at local building.

With old analogue this could produce ghost images and one look at TV screen and one knew what the problem was. But with digital all you have is TV's built in bar graphs showing signal strength and quality.

High strength low quality then reflected signal or other interference. Low strength then aerial or booster at fault.

Electric storms can take out boosters and I found removing booster improved signal a sure sign of booster failure. Changed and all OK.

So step one turn off all boxes Sky, VCR etc. Does picture improve. If so something needs re-tuning. Bypass booster just for one TV to test if picture better well sure you know booster US. Get a TV as close to loft as you can and use patch lead if better coax is faulty.

All easier than climbing on roof.

Give more detailed report here as to signal strength and quality. Work out which multi-plexers have problem and look at frequency. Tune TV to same frez on analogue and see if there is a signal. Some times neighbours Sky box can transmit on Freeview channel.

 

[IJWS15]

Started investigating yesterday afternoon, pulled out the Video recorder to isolate it and the Film 4/ITV4 pictures appeared.

Looks like a poor connection in one of the leads has been affected by something being moved.

Going to re-make the connections tonight with some better plugs and see how that goes.

At lease I got to see Lance Armstrong's disaster in the Tour-de-France yesterday afternoon.

 

[IJWS15]

Problem appears to be solved, tried re-making the aerial lead but the chep connectors had no fixing for the central core and when i tried soldering it in the insulator melted.

New connectors bought (with screw fixinf for the central wire) and now have ALL channels back.

Still don't understand why the poor connections affected some channels and not others.