FAO Garry please (re Aerials !!)

[JohnI.Stephen]

In my recent discussion all about aerials we concluded that I probably needed to buy both a new aerial and coax. The aerial engineer came round this morning; tested the signal and then reviewed his readings against my HUMAX, which showed that I get 67% signal strength and 100% quality on Channel 5 (the dodgy channel for me). He couldn't understand what the problem was because we had a clear bright picture. Suddenly it happened; a blank screen with 'no signal' being displayed. I quickly went to the HUMAX signal meter; still 67% signal strength but the quality was down to ZERO! We watched it for a minute or so; signal quality then rose to 10%; and then dropped to 0; then suddenly it was back up to 100% and the picture was restored.

Whilst my aerial engineer was scratching his head, I was concluding that this was most likely interference. I checked channel 5; it seems to be broadcast at approx 690Mhz whereas BBC1 is around 110Mhz less a 580Mhz. I may be off track but it seems that this is the most likely cause. What do you think Garry? And if I am right, what's to be done?

Thanks !

John

 

[JeremyClarksson]

I get perfectly good digital reception on a lot less than your readings, but you are losing it because the quality is detiorating so much.

I am assuming that you are now working with a new (high gain?)aerial and coax.

Have you tried an amplifier yet?

Was the aerial engineer aware of any localised problems?

I would watch it for a while and compare it with what happens on BBC1 i.e does that drop at the same times, if you have got the Humax with twin freeview decoders that should be fairly easy.

It might be worth trying another freeview box to see if that makes any difference.

If none of those work it could be the difference in frequency or it could be that the CH5 transponder is transmitting at lower power, in which case you could try another channel on that transponder.

I will have a look at how to find out what transponders do what but you can get this info from your freeview box as well.

 

[JeremyClarksson]

CH 5 frequencies and transmitter power

http://www.bbc.co.uk/reception/transmitters/tv_trans/tv_c5.shtml

 

[JohnI.Stephen]

Garry; all of this is with my current (old) setup. aerial guy said that the amplifier was working well and that the signal he was getting was really fine. So the question remains; what could cause the quality (not the signal strength) to drop to zero whilst the signal strength maintains a steady 67% ?!!

John

 

[JeremyClarksson]

Forget that last post - analogue

Digital from here

http://www.dtg.org.uk/retailer/transmitters.html

 

[JeremyClarksson]

Forget that last post - analogue

Digital from here

]http://www.dtg.org.uk/retailer/transmitters.html

http://www.dtg.org.uk/retailer/transmitters.html[/quote
re. your last post.

If it is measuring the CH5 signal strength rather than overall transmitter strength than I find it difficult to equate a total drop in quality with little drop in signal without some kind of transmission fault.

Did you try the other things I suggested i.e. what happens with BBC1 at the same time and perhaps trying another freeview box?

 

[JeremyClarksson]

There might be ongoing work on your txer try this

http://www.bbc.co.uk/reception/transmitters/today.shtml