I have read through a few threads on this board and am not sure which course of action to take regarding my signal problem as there seem to be many different pieces of advice out there and I am not 100% confident that I have nailed down the specific cause of the problem.

When using the Humax 9150t:
My signal strength is usually at around 80% or higher.
My signal QUALITY is the one the goes from 100%, down to 40%, up to 100% then down to 50% etc...

I have deleted all channels from memory and retuned manually following the advice on other threads; unfortunately this hasn't helped to solve the quality problem (although it did provide a small boost in signal strength.)

I have a 3 year old Sony LCD TV with built in Freeview. When I attach the aerial cable to the TV directly, I get all channels with NO distortion or clipping etc.

As soon as I attach the same cable to the Humax, the signal quality starts to fluctuate etc.

The freeview aerial only provides a signal (even to the TV-only option) when I switch on the amplifier/booster downstairs, which the aerial connects to from outside, so trying the aerial straight in to the Humax without the amplifier seems to be a no-go at this stage.

Do you think that the amplifier is providing TOO MUCH signal to the Humax, and therefore I should try a signal attenuator?

I am not sure whether I should be:

A) buying some new aerial cable to try with the humax
B) buying a signal attenuator to see if the current signal is too strong for the humax
C) considering a new aerial installation (this seems silly when the Sony TV works perfectly "as-is")
D) any other/better option?

I will appreciate any advice

Can you describe exactly how your aerial system is connected up?

How does the aerial signal get from this "booster" to the Humax? Or is the "booster" actually powering a masthead amplifier/splitter elsewhere that distributes the signal to various rooms? ie no direct cable connection from this "booster" to the Humax.

At 80% I wouldn't have thought the signal was too high. But an attenuator is not expensive so could be worth trying. But no guarantees.

The cable could have an effect. If it is cheap poorly screened stuff then it could be letting in all sorts of interference. But that would/should also affect the TV to some degree. Though I have noticed with both my Humax boxes that they can be more susceptible to interference than my TV. On more than one occasion over the summer I have had break up on a channel on the Humax but fine on the TV.

Thanks for the quick response

It is a house I recently moved in to, so the set-up was not done by me...

The aerial feeds down the outside wall and into my downstairs room. When it gets through the wall the cable is only about 30cm long (so not long enough to feed directly into a receiver or TV etc) and this cable goes straight in to the amplifier.

I have an aerial cable in the upstairs bedroom and this may be fed through the wall from the aerial outside (I say may because when we looked the 'entry' point on the outside wall doesn't seem to tally up with where the cable actually enters the bedroom inside) - it is not directly fed into the amplifier downstairs.

If I switch off the amp and try the cable upstairs, I get a 'no signal' alert on the TV. If I switch on the amp, the signal is there and the reception is great (only when fed directly into the TV.)

I guess this means that the amp downstairs must be feeding something that is physically attached to the masthead/aerial outside, although I am not 100% sure of this.

I have tried using the cable in the bedroom (with amp on) and get a signal using the Humax but it is the fluctuating one I was talking about earlier.

I have also tried taking a cable from the 'TV out' on the amp/booster itself downstairs (into a TV located next to it, not feeding the cable all the way upstairs lol) and I get the same - decent signal but fluctuating quality.

There is also a satellite dish on the wall, located a few metres below the TV aerial. I have 1 cable entering the house from that (through a hole just below the cable coming from the aerial) and I use this to feed a Humax FREESAT receiver - I have an excellent feed here with no problems in signal or quality.

Could the dish be causing interference possibly?

One other thing that may be worth mentioning.

The cable in the upstairs bedroom enters from the opposite wall to where I want the TV to be so I have coupled another aerial cable onto it to reach the desired length. It actually enters the room from the opposite wall to where the aerial is positioned outside! In effect the cable must enter the house then run underneath the floorboards to the opposite wall, where it comes out into the room!

I appreciate that 'daisy-chaining' means there are more pieces of cable and connections that could be problematic but this same 'daisy-chain' is the one that feeds the TV which receives an excellent signal on its own...

Finally, the test I did downstairs (straight from booster to Humax) used only 1 cable so there wasn't a daisy chain - I did use the cable from the chain though (I brought it down from the bedroom).

It would be nice if the problem was all down to this cable, although I don't expect that it will be that easy...

Thanks

Does the device downstairs look something like this?

http://www.labgear.co.uk/assets/imag...52-1-large.jpg

Doesn't have to be identical but the main thing is that it only has two sockets on it, on for the aerial cable and one for the cable to the TV? If so then chances are you have a masthead amp and what is downstairs is the power supply for it. Which explains why the TV point upstairs dies when you turn this device off

There should also be a small, usually square, box attached to the aerial pole. That will be the amplifier itself. There is a possibility that this amplifier is being overloaded. Or it could be faulty. But again if either of those applied you should see some effect of that on the TV as well.

Could the cable to the upstairs room enter above the ceiling and drop down the cavity wall perhaps?

The satellite dish shouldn't affect the TV signal. Though if they were very close together the physical presence of the dish might have an effect. You can certainly get odd effects by having two TV aerials a foot or so apart. But a few metres should be fine.

But what are the visible effects of this varying quality readout though? I've seen similar on both my Humax boxes and the TV and most of the time there is nothing visible on the TV screen to show that the quality is fluctuating. No break-up or any other artefacts to show there is any problem. So what are you seeing?

The video constantly lags or even pauses for a few seconds, usually while the audio continues as normal.

Another issue is there is a lot of digital 'clipping' of the audio - sounds just like general digital distortion (almost 'wet' or 'watery' in sound)

I'm not getting massive horizontal breaking up of the picture - for the most part (following my manual retune) I get a decent picture but it just consistently pauses and stutters.

I have gone through the installation menu and set the 'signal strength' to show on the screen and this is where I can literally see the quality % fluctuating while the video and audio both stutter and pop.

And yes, I am certain that the amplifier downstairs is what you suggested - a power supply for the amplifier on the aerial... Thanks

Not sure how practical this is for you but...

Is there any way to try your Humax in another location? Ideally in place of someone else's 9150 that you can see works perfectly, but mainly one where the "resident" kit shows a nice solid signal and quality readout. And a nice solid disturbance free picture.

Put your 9150 in place of the "resident" unit and compare how it performs. If you get similar issues to how it behaves at home then that could indicate a faulty 9150. If it performs perfectly then you may have a signal problem.

Again ideally you would use another unit on your aerial in place of your 9150 to see if that suffers similar problems. Again that will indicate if the problem is the aerial or the 9150.

I would normally also suggest trying a different SCART lead to the telly. But what you describe doesn't sound immediately like a SCART problem. The sort of picture issue you describe, plus the readouts on the Humax, do tend to suggest the problem is on the input not output side of the Humax, ie the aerial or the tuner/decoder stages in the Humax.

If the masthead amplifier is being overloaded then that would need sorting at the masthead, putting an attenuator in the aerial input to the Humax isn't going to solve any signal corruption that's occurred in the amp. It would only solve any overload of the Humax tuner. As I posted earlier an attenuator is only a few quid so worth a punt.

But I would suggest that if at all possible you try your 9150 away from home just to help narrow down where the problem lies. After all you don't want to spend a small fortune getting an aerial rigger out to look at the aerial installation then discover the 9150 has gone belly up. Or conversely buy a new PVR only to find the masthead amp has fried!

Plenty of food for thought there, thanks so much

I have just bought the Humax via Ebay, where it was described as almost new in condition. The unit certainly looks clean and tidy, and the record function works etc. I just hope that the internal part isn't faulty cos that will bring a new problem into the mix!

I will try and use the unit in another property that has freeview and also use another separate freeview tuner in my house.

Can I post in here again when I have tried this?

I have tried a 6db attenuator both downstairs and upstairs in my home - this made little/no difference

I have tried using my box in the house next door (with and without the attenuator) and it still suffers from the same stuttering video and audio problem. This problem still persisted following ANOTHER manual retune. As with my house, they get a perfect signal on their TV's inbuilt Freeview tuner and with other, non-HUMAX, freeview boxes.

I have tried using a variety of scart leads and aerial cables and these have also had no effect on the problems.

I am therefore left with the problem of:
A) considering replacing my external aerial and/or masthead amp
B) giving up and trying to return the unit to the Ebay seller (this would be a shame as the unit does seem to be in great condition apart from the signal problem)

Would you recommend anything else before I decide between A and B?

Thanks again.

Have you tried another unit on your aerial? Though if your Humax has the same issue on two separate aerial systems tends to suggest it's not the aerial. unless by some weird chance you both have absolutely identical set-ups with identical characteristics.

Based on my experience with my own 9150 I'm tempted to suggest yours has a fault. Mine has been pretty much rock solid. The only issues it has had are during certain atmospheric conditions when it occasionally breaks up due to interference. But never for very long normally.

I've actually got two Humax's, the 9150 and a Fox-T2 for Freeview-HD. I use the Fox-T2 a lot more than the 9150 now as my TV doesn't do Freeview HD by itself. So I would soon notice any issues with signal.

All of which is leading me to think your Humax is less than 100% fighting fit. So of your two options I'm favouring B. I'd be more inclined towards A if your Humax had worked perfectly in your neighbour's house. That it didn't makes me think your aerial may be OK.

Chris

I have found that rapidly varying signal quality like that is usually co-channel interference - see Post 8 here http://forums.digitalspy.co.uk/showt...671&highlight= and Post 14 here http://forums.digitalspy.co.uk/showt...0#post68814460

Thanks for that extra info John.

I did in fact wonder whether the amount of 'rocking' my aerial did in the wind would have any impact. In the end I returned the box as I don't think all the messing around (forwards and backwards placement) with the aerial will be worth the hassle, considering that my Sony receives a perfect signal as it is.

I appreciate your extra input though because if I decide to get a different receiver, I may have to go down this route in the end!

Thanks again