What's Happened to This Multiplex?

#1
Since the recent required re-tune at the Sudbury transmitter, I have noticed that all the channels on PSB1 BBCA (channel 44) are badly pixellating on some days (today bad, for instance). Radio channels on this mux are also breaking up.

Checking the signal data today, I see this is coming in at strength of around 35% or less with quality ranging from 10%-50%. There was no such problem with this mux prior to recent re-tune and all other muxes are showing the usual strength around 60% and quality at 100% and have not suffered picture break-ups etc.

I have tried a manual re-tune of this frequency and the result is exactly the same.

Any thoughts on why only this mux is behaving this way, and what can be done to resolve it?
 

prpr

Well-Known Member
#2
Interference (local), interference (atmospherics - weather related), lack of signal due to some problem with your receive infrastructure (aerial/cabling).
Fault-finding by substitution (take your kit somewhere else), use different kit on your aerial, or get someone in with suitable measuring equipment.
It's probably not a transmission problem, although it's not unheard of - try asking around other people in your vicinity.
 
OP
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lancer

New Member
#3
Don't think it's kit related as not specific to the Humax. There are also three televisions attached to the aerial and another Humax in different parts of the house and all are plagued by the same thing.
Could be some sort of local interference, I guess, although weather seems to affect more than one mux when we get that issue and doesn't persist as long as this has.
Seems to have started as an issue over the last week.
 
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prpr

Well-Known Member
#6
There are also three televisions attached to the aerial and another Humax in different parts of the house and all are plagued by the same thing.
You have got a proper splitter/distribution amp. for all this, haven't you?
Seems to have started as an issue over the last week.
The last change at Sudbury was in Feb. and that only affected COM6, not PSB1.
 

Trev

The Dumb One
#7
I have suffered what I think is co-channel interference from the ontinent on and off on various multiplexes from Hastings for a few weeks now. It seems to come and go in the spring and autumn.
I have got two aerials mounted in different places and switching between the two seems to enable me to watch what I want.
As a last resort, I can watch Freesat on my TV.:)
 
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lancer

New Member
#8
You have got a proper splitter/distribution amp. for all this, haven't you?
Now, what do you think?!
Have had for years!
We can occasionally get interference from the continent when atmospherics are right (are they right now?!). Is it reasonable that it would only affect channel 44 leaving all others ok?
 

prpr

Well-Known Member
#9
Have had for years!
OK, but the question has to be asked. It's not uncommon for people just to jam more and more cables into the connector box even though they don't fit and then they end up surprised when things don't work properly.
We can occasionally get interference from the continent when atmospherics are right (are they right now?!).
Probably, if it's only been happening for a week.
Is it reasonable that it would only affect channel 44 leaving all others ok?
RF is funny stuff. Virtually anything can happen. The trouble with digital is that you don't get any warning like you did on analogue.
If it doesn't change when the weather does, then it points more to your installation. You might have a degraded cable somewhere for example, which could be introducing frequency selective notching.
Back to post #2.
 

Trev

The Dumb One
#10
When I get what I think is CCI, it affects varius MPXs. Sometimes only one. BBCB is often the case, but it varies, sometimes different ones and sometimes multiple ones.
Whatever, when it 'comes back' I get 100% quality and a good signal level (stating % is pointless).
If your CH44 is constantly bad, then do as prpr said in post #2.
 
#11
I'm on Sudbury and the signal on CH44 is currently showing as strength 74-76%, quality 100%. I don't use any of the channels so can't comment on recent performance.
 
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