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Aerial feed to tv

Robti

Member
Hi all I am looking to reconnect my aerial feed to my tv for watching tv in the morning and wondered how you all are connecting it, splitter or loop through out of the box
 

MikeSh

Well-Known Member
Splitter (passive) depends on your signal strength as it will drop it by at least a half (3db).
Loop through means the box must be at least half awake to work, or you have to disable some power saving in standby which will obviously use a bit more electricity (not much but 24/7 can add up).
Active splitter or amp will also use more power and cost more upfront.

So if you have the signal I'd definitely go passive splitter, which is what I've done.
 

Black Hole

May contain traces of nut
I hardly ever use my TVs' own tuners, it wouldn't bother me not to have the aerial linked at all.

There is no reason to go to the complication of splitters unless you have a specific need: are you keen to save a few pennies by enabling the HDR's low-power-in-standby setting? See Things Every... (click) section 7.
 
OP
Robti

Robti

Member
Thanks all I think I will try a passive splitter and see how I get on, I have all my av equipment in a cabinet and at night when viewing ( Humax box & amp or blue ray & amp) I leave the door open for cooling and want to just use the tv in the morning to catch the news and not switch everything on
 

Trev

The Dumb One
You do not have to have the Hummy switched on for loop through. Just disable the low power standby.
 

EEPhil

Number 28
"If it ain't broke don't fix it". And to quote BH It's only telly. I'm not really bothered by the latest ultra-hd tv just to watch old b/w films and tv programmes. The old crt will do fine until it breaks down.
 
OP
Robti

Robti

Member
Hi just to update in case anyone searches in the future fitted a lab gear passive splitter and the signal dropped slightly from 71% to 64% with quality staying @ 100% on the weakest signal and I am happy with that
 
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everthewatcher

Forum Supporter
Hi just to update in case anyone searches in the future fitted a lab gear passive splitter and the signal dropped slightly from 71% to 64% with quality staying @ 100% on the weakest signal and I am happy with that
A decent inductive passive splitter will drop the signal by little over the expected 3dB - say 4dB - as there'll be losses on top of the signal split, plus you'll get odd effects if one side of the splitter isn't terminated with the expected 75ohm impedance.

IME inserting a 10dB attenuator here drops the signal from an indicated 90% to around 80% but I've yet to try 3dB and 6dB ones. I may report back...
 

Trev

The Dumb One
Please do with your findings.
But as the signal level measurement is pretty arbitrary across different manufacturers, the results, although interesting, will not reflect what can be expected on a different make of TV or perhaps even different models from the same manufacturer.
Now if they calibrated the signal level in dBm (or some other standard measurement units), then that would actually mean something as opposed to a percentage of some arbitrarily set 100%.

I have not found any difference between terminating unused outputs and leaving them un-terminated. Although the purists will always advise correct termination. Any untoward un-terminated effects will probably depend on the path length within the splitter and the frequency in use causing additive or subtracting reflections from the un-terminated port.
 

everthewatcher

Forum Supporter
But as the signal level measurement is pretty arbitrary across different manufacturers, the results, although interesting, will not reflect what can be expected on a different make of TV or perhaps even different models from the same manufacturer.
Well yes, but we're talking about the HDR here. You'll probably find that the RSSI value reported by the tuner will be pretty tightly defined, but there's no knowing what's done with it in order to display it. Based on what I've seen with a couple of units, some cheap simple STBs seem to be set up so that anything over a good enough signal is displayed as 100%.
Now if they calibrated the signal level in dBm (or some other standard measurement units), then that would actually mean something as opposed to a percentage of some arbitrarily set 100%.
That would be useful. It's the kind of thing that might be hidden somewhere on a development menu.
I have not found any difference between terminating unused outputs and leaving them un-terminated.
YMMV. I've seen an entire multiplex vanish due to a termination problem so I don't take the risk. Unused inputs on distribution amps also get a terminator.
Any untoward un-terminated effects will probably depend on the path length within the splitter and the frequency in use causing additive or subtracting reflections from the un-terminated port.
Yes, that's what happens.
 

Trev

The Dumb One
YMMV. I've seen an entire multiplex vanish due to a termination problem so I don't take the risk. Unused inputs on distribution amps also get a terminator.
OK. I'll bear that in mind. Thanks. It's just that I have not had problems before with TV stuff, but being from a radar technician background, I do appreciate the need.
 

MikeSh

Well-Known Member
A decent inductive passive splitter will drop the signal by little over the expected 3dB - say 4dB - as there'll be losses on top of the signal split, plus you'll get odd effects if one side of the splitter isn't terminated with the expected 75ohm impedance.

IME inserting a 10dB attenuator here drops the signal from an indicated 90% to around 80% but I've yet to try 3dB and 6dB ones. I may report back...
When I added a diplexer, which was specified to lose 1db, I lost 1 or 2% on the HDR display depending on how you read it and the mux. So for 4db losing 6 to 8% seems right to me. (These were signals in the 50 to 80% area.)
 

everthewatcher

Forum Supporter
IME inserting a 10dB attenuator here drops the signal from an indicated 90% to around 80% but I've yet to try 3dB and 6dB ones. I may report back...
A 3dB attenuator dropped the signal from 86-87% to 82-83% and what I thought was a 6dB attenuator is another 3dB one.

But it does look like, at least at this part of the range, 1% is 1dB.
 

everthewatcher

Forum Supporter
A 3dB attenuator dropped the signal from 86-87% to 82-83% and what I thought was a 6dB attenuator is another 3dB one.
Yes, I know [I can stack the attenuators]. My excuse is I'm nursing an absolute stinker of a cold, which is why I'm home.

Starting from 86%, a 3+3dB attenuator drops the indication to 79-80% and 3+3+10dB to 70%.

I'd say that was pretty conclusive.
 
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