Where to get best quality Freeview fly lead?

Rambles

Distinguished Member

Ged

Active Member
Ah.. so is the distribution amplifier mains powered? I assumed it was powered by a separate power supply... sorry. In that case my information is invalid.
 

Rodders53

Distinguished Member
The DA is mains powered from a socket in the loft (if I remember correctly).
Why it cuts out when there have been power outages is anyone's guess.
Whether the whole device or just the masthead 12V out from it, ditto? The plan to have a separate 12V supply may diagnose which?
I'd probably have fitted a smart or wireless mains socket to power off and on the DA for when this lockup occurs if I had a similar problem as I have a few lying around.

Aerial adaptors will introduce a potential impedance mismatch and a tiny insertion loss. In practice neither is likely to give problems. But the signal level is not your problem so some loss would not harm reception.

You have too much amplification and that allows distant co-channel interference to distort the wanted, courtesy of the lack of antenna directivity.
 

Rambles

Distinguished Member
The DA is mains powered from a socket in the loft (if I remember correctly).
Why it cuts out when there have been power outages is anyone's guess.
Whether the whole device or just the masthead 12V out from it, ditto? The plan to have a separate 12V supply may diagnose which?
No, we don't have a loft, the house was built with rooms in the roof space. All of the cables terminate to a cupboard under the stairs which is where the DA is situated.

The TV's losing signal haven't been in relation to any power cuts.

I am trying / hoping to diagnose a fault with the 12V DC output from the DA to the MA.

I'd probably have fitted a smart or wireless mains socket to power off and on the DA for when this lockup occurs if I had a similar problem as I have a few lying around.
Yes, good idea, except that the problem is not so much with live TV, but with recordings. We have a server that does our TV recordings. and we need to trust that it will work, as we could go a few days without watching any live TV and not know that the signal has disappeared.

Aerial adaptors will introduce a potential impedance mismatch and a tiny insertion loss. In practice neither is likely to give problems. But the signal level is not your problem so some loss would not harm reception.
Good to know - thanks!

You have too much amplification and that allows distant co-channel interference to distort the wanted, courtesy of the lack of antenna directivity.
But the variable attenuator that I added in to the system made no difference o_O
 

Rodders53

Distinguished Member
But the variable attenuator that I added in to the system made no difference o_O
Because it is after the culprit amplifier within the omnidirectional amplified aerial. Garbage in = garbage out, just at at differing levels.

This is why a directional aerial is used to maximise the wanted and reduce unwanted signals via the polar gain curve.

When you install the 12V masthead supply test to see if the server PVR tuners can be fed direct (albeit one at a time initially to measure level and quality on every frequency).
Next try passive splitting rather than active/amplified, two ways -4dB, four ways -8dB. Then use the DA to feed the TVs via an output from the passive splits?

Consider relocating the psu as far away from the server kit as you can. I'm suspecting a possibility of computer hash on earthy coaxes might be triggering something? Difficult to prove, naturally.
 

Rambles

Distinguished Member
Because it is after the culprit amplifier within the omnidirectional amplified aerial. Garbage in = garbage out, just at at differing levels.

This is why a directional aerial is used to maximise the wanted and reduce unwanted signals via the polar gain curve.
Yes, I appreciate that, but changing the aerial is not really on the list of options at the moment, so I'm trying to do what I can with the one I have.
When you install the 12V masthead supply test to see if the server PVR tuners can be fed direct (albeit one at a time initially to measure level and quality on every frequency).
Next try passive splitting rather than active/amplified, two ways -4dB, four ways -8dB. Then use the DA to feed the TVs via an output from the passive splits?
I have tried that as I only have one wall plate in the room where the server is , and I have multiple tuners to feed. I use an active splitter (one of the Proception ones actually that you linked to earlier, a 4 way one). So, I took that out to test and added in a passive splitter, and the signal was worse rather than better. This was using the signal information on the Sony TV in that room, with the quality / strength signal meters and the error rate readings.
Consider relocating the psu as far away from the server kit as you can. I'm suspecting a possibility of computer hash on earthy coaxes might be triggering something? Difficult to prove, naturally.
That we can rule out. The distribution amp is in a cupboard under the stairs on the ground floor. The server is in one of the bedrooms on the 2nd floor.

Earlier on you mentioned something shorting out. I just want to clarify that if I add the separate PSU for the masthead amp into the system, that will then feed the main input on the distribution amp, which in turn has the 12V DC output on that very input. Did you mean that will short out, so will not send power back into the PSU? There is no option to switch that off, and I am bit confused about how that would work.
 

Rodders53

Distinguished Member
The DA has a 12V supply it auto switches on... If it detects a short circuit (such as an an unamplified TV aerial, a passive splitter output, or possibly the masthead supply output, it shuts down that 12V supply (via a simple transistor circuit that detects the excess current).
It will repeat that process every time mains power is first applied to the DA, or the input RF cable is disconnected/remade.
No harm will be done.

The masthead psu likely has no DC connection path between the out and the aerial in anyway: this diy inserter may help explain? Make a DC inserter
 
Last edited:

Rambles

Distinguished Member
Thanks for the info - the link doesn't work though.

I have ordered a few bits and pieces from TLC to experiment with, lots of F-plug / coax connectors and adapters and some passive splitters. Will have a play with it all and see if I can learn more about what helps and what hinders!
 

The latest video from AVForums

Panasonic HZ2000 OLED TV Review: The best OLED for movie viewing in 2020
Top Bottom