Another RF pass-through question...

mike_m

Active Member
I understand how RF pass-through works with the Power Management settings; however, I'm not sure what the position is when the Humax is powered down at the mains.

I ask because I think the behaviour has changed with my new smart(er) TV (in both cases, the Hummy's power management settings are OFF - OFF):

Old behaviour: If I turned on the TV with a Humax selected as the source, but that particular Humax was turned off at the mains, the TV it would show some sort of error message about there being no signal; however, if I then changed the source on the TV to another Humax, or to the TV's own RF input, it would show live TV as normal, showing that RF pass-through was operating even when the Humax was turned off fully.

New behaviour: I turn on the TV, it displays an error message says that there is no aerial signal, and this persists even if I change to another source. The signal is only restored if I power up the Humax.

Any idea why this might be?
 
RF pass-through doesn't operate when the device is turned off. What you are seeing is probably a very attenuated signal which sometimes is enough to drive the TV and mostly isn't.
Either leave the device on, or use a splitter upstream.
 
I turn on the TV, it displays an error message says that there is no aerial signal, and this persists even if I change to another source.
Are you saying the TV complains about a lack of aerial signal, even with an active HDMI source selected??? If so, the TV is too "smart" for its own good. It really shouldn't do that.

Expanding on prpr: the RF path comprises an input buffer and an output buffer. With no power, they don't operate and any signal is just bleed-through.
 
Are you saying the TV complains about a lack of aerial signal, even with an active HDMI source selected??? If so, the TV is too "smart" for its own good. It really shouldn't do that.
The RF feed daisy-chains through the 2 Humaxes before reaching the TV, so if the first Hummy is powered off, I guess the RF signal doesn't go any further, and the TV correctly reports no RF feed at all.

I always have the Humaxes on, so this problem isn't something I usually encounter. I realise that my original post was incorrect - on previous occasions when the TV reported a loss of signal from one Humax, while the other sources still continued to function, it must have been because the Hummy had locked up or was otherwise indisposed, but still had power, and so the pass-through was still operational.

In this recent case my network monitoring tool had detected that a Hummy was unresponsive and had power-cycled it just at the moment that I'd switched on; a pure coincidence. But perhaps it's worth using splitters so that all devices have an independent RF supply - or would that lead to an attenuated signal?
 
But perhaps it's worth using splitters so that all devices have an independent RF supply - or would that lead to an attenuated signal?
It will attenuate the signal a bit but if you have a reasonable signal strength (maybe above 60%) then it should be OK.
 
But perhaps it's worth using splitters so that all devices have an independent RF supply - or would that lead to an attenuated signal?
It will, but you've probably got enough to start with. If you haven't then a single in/out low gain amp. upstream of the splitter will do the job nicely.
But try the splitter by itself first - and use proper metal screened ones with F connectors and adapt as necessary.
 
I have a problem where when recording say BBC2 HD, and watching BBC2 SD, the later is pixilated, any ideas? Both signal and strength are 100% across the spectrum.
 
I have a problem where when recording say BBC2 HD, and watching BBC2 SD, the later is pixilated, any ideas? Both signal and strength are 100% across the spectrum.

Strength = 100% might be a problem, because the meter maxes out at 100% so could be 1000% for all we know. Too strong a signal can result in clipping in the input stages and loss of data. This will show up in the quality figure.

There is only one way to get a view of the signal strength and quality, and that is to select the UHF channels in turn through Menu >> Settings >> System >> Signal Detection and watch the meter bars for several tens of seconds to see how stable they are.

Other things can affect the output video: HDMI cross-talk to the aerial lead and HDD problems, to name but two.

Quick Guide to Disk Recovery
 
however, if I then changed the source on the TV to another Humax, or to the TV's own RF input, it would show live TV as normal, showing that RF pass-through was operating even when the Humax was turned off fully.

New behaviour: I turn on the TV, it displays an error message says that there is no aerial signal, and this persists even if I change to another source.
So it was the "other source" reporting lack of signal, not the TV.
 
So it was the "other source" reporting lack of signal, not the TV.
Yes, when the source was the other Humax (downstream from the switched-off Humax); when source was the TV's own tuner or the switched-off Humax, then it was the TV reporting it.
 
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OK point taken, what I have done is attenuated the signal from the mast amplifier into the box, and now the pixilation has gone, so perhaps the tuner was overwhelmed by the signal.
Once again thank you for helpful comments.
 
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