Problems with viewing BBC4HD on one tuner only


New Member
Hi all. I've been having intermittent issues viewing and recording BBC4HD since it began broadcasting (I'm on Crystal Palace) - I don't think this is the same as the broken recordings issue elsewhere as it's also clearly visible when just viewing the channel.

Sometimes it's fine, but more often it's either very glitchy or (more often again) no signal at all. This also affects the other channels on the same mux; all other channels (SD and HD) are always fine. I'm aware the BBC4HD mux is a lower strength than the other muxes, but my TV (Samsung) is always able to receive it fine.

I spent some time last weekend trying to work out why this problem didn't always happen and finally discovered that it seems to affect only one tuner on the Humax. Basically if I start recording something on a different mux then flick over to BBC4HD, it's 100% fine (no glitches at all). If I stop recording, change channel away from BBC4HD and back again, it's glitchy/gone.

I've tried comparing the signal strength of the two tuners using the hidden menu, but I'm not sure it's reliable. I always see the same strength and quality for both tuners - about 70% strength/100% quality for "normal" muxes, and 35-40% strength and variable (from 100% down to 0%) quality for BBC4HD.

However... if I first do the "record something from another channel" trick, flick to BBC4HD (which is now fine) then check the tuners on the hidden menu, I see 50% strength and consistent 100% quality for the BBC4HD mux (again, the same figures are reported from both tuners).

I've concluded from this that the hidden menu signal strength screen only ever shows the current tuner... is this a known issue?

However my main query is - is it expected to have a 10%-15% signal difference between tuners? If not, is there anything I could check for a dodgy connection (clutching at straws here). I'm assuming that 35% signal strength is just too low for the Humax to cope with.

Maybe also worth mentioning that my TV (which is connected after the Humax to the aerial lead) reports 90% signal strength for normal muxes and 70% for BBC4HD - is the Humax generally more picky about its signal?

Thanks for any help/insights. I'm running custom FW 1.02.32/2.21.
You can't compare "signal strength" between different items of equipment, you have no idea what they take as their datum.

Ultimately what you are interested in (for a digital signal) is "quality" - 100% says you are getting no detectable data errors (or possibly no uncorrectable errors, not sure). If you have 100% quality, then the strength figure gives you and idea how close you are to losing the quality because of too weak a signal, or too strong.

As to your tuner problem, I have no idea.