Signal dropouts (signal strength 30% - is this too low?)

[Ian Manning]

The only reason for using the signal test on the service menu is if you suspect only one tuner is working (and clearly they are giving the same performance). So far as I know there is no option in the service menu version to change the UHF channel for the test. Using Menu >> Settings >> System >> Signal Detection doesn't offer a choice of tuner - but does allow you to survey all the tuned muxes. I recommend you do that

Presumably I do that simply by selecting each transponder on the Signal Detect screen and pressing the Enter button? If so, the results show 25-30% Strength for all transponders apart from 48200MHz, which jumps between 30% and 36%.
Quality shows as 100% for all 6 transponders.
I'm using the exactly the same RF cable for the TV and Humax - unplugging the cable and switching it between the TV and the Humax.
So if the signal strength isn't good enough for the Humax (25-30%) I'm guessing that any aerial improvements could only be marginal if the TV is already reporting 93% strength? Would it be worth getting somebody up on the roof do you think?

 

[Ian Manning]

Oh yes there is - I'm looking at it now.

Are you referring to the option to select between the 5 transponders? If not, which option are you referring to?

 

[everthewatcher]

Are you referring to the option to select between the 5 transponders? If not, which option are you referring to?

That's the one, although here I've got the eight the HDR is tuned to.

 

[Black Hole]

Oh yes there is - I'm looking at it now.

Oh yes, so there is. Unfortunately it only displays frequency not channel number, so it is less convenient (I think in channel number, because that is what is normally used when discussing TV broadcast channels/muxes). I am bemused that the OP insists on using the service menu rather than the signal detection in the System menu.

do I only need to search the 7 channels listed in the "N" column from the Freeview site detailed view?

Yes, exactly that (and make sure you select DVB-T or DVB-T2 appropriate for each one).

I'm guessing that any aerial improvements could only be marginal if the TV is already reporting 93% strength?

Why? What signal voltage does the TV call "100%"? You don't know and I don't know either. All you know is that the Hummy is reporting 25% (or whatever) and getting dropouts. You still want to know what that looks like when the dropouts are actually happening, and the reported quality at the time. If the quality remains 100% you have to start looking at whether its disk thrashing that's causing it, rather than signal.

If the dropouts are due to signal, you might only need to lift it by a few percent.

 

[everthewatcher]

Presumably I do that simply by selecting each transponder on the Signal Detect screen and pressing the Enter button? If so, the results show 25-30% Strength for all transponders apart from 48200MHz, which jumps between 30% and 36%.
Quality shows as 100% for all 6 transponders.

That's the way.

I'm using the exactly the same RF cable for the TV and Humax - unplugging the cable and switching it between the TV and the Humax.

Good - it eliminates any other variables. Only thing I might suggest is try a different flylead just in case there's an issue with it not mating properly with the HDR. Ah, that's another possibility to eliminate - is the RF in connector broken? Easy enough to check. With the TV plugged into the HDR's RF Out does the TV still report >90% (or whatever) signal strength?

So if the signal strength isn't good enough for the Humax (25-30%) I'm guessing that any aerial improvements could only be marginal if the TV is already reporting 93% strength? Would it be worth getting somebody up on the roof do you think?

It wouldn't be the first time I've seen a TV report 100% signal when the HDR reports a lot less. Here the HDR reports 75% on Ch55 (the lowest) but the Panasonic TV reports 10. If I put in a 10dB attenuator it drops to 8 with errors so it's clearly non-linear. The HDR drops from 75% to 54% with a signal quality of 100%.

 

[Luke]

do I only need to search the 7 channels listed in the "N" column from the Freeview site detailed view?

For your 'local' channels also 35.

 

[Ian Manning]

That's the way.

Good - it eliminates any other variables. Only thing I might suggest is try a different flylead just in case there's an issue with it not mating properly with the HDR. Ah, that's another possibility to eliminate - is the RF in connector broken? Easy enough to check. With the TV plugged into the HDR's RF Out does the TV still report >90% (or whatever) signal strength?

Ah....we could be getting somewhere....if I connect the RF out from the Humax to the TV I get zero signal on the TV. So maybe the Humax's RF connector is broken? I have an old HDR-Fox T2 in the loft (broken fan IIRC). How feasible/easy is it to swap the RF hardware between units?

 

[Black Hole]

if I connect the RF out from the Humax to the TV I get zero signal on the TV

That could mean you had the Humax unpowered, or in standby with low power mode set (no pass-through), or your link cable is broken. Easy enough to insert the link cable in series with the direct cable to the TV to check.

(broken fan IIRC). How feasible/easy is it to swap the RF hardware between units?

It would be a lot easier to simply swap the fan!

https://hummy.tv/forum/threads/hdr-fox-hardware-commissioning-disassembly-repair.5728/

 

[Ian Manning]

That could mean you had the Humax unpowered, or in standby with low power mode set (no pass-through), or your link cable is broken. Easy enough to insert the link cable in series with the direct cable to the TV to check.


It would be a lot easier to simply swap the fan!

https://hummy.tv/forum/threads/hdr-fox-hardware-commissioning-disassembly-repair.5728/

The Humax was powered on when I tried it, so presumably would have been passing the RF signal through. I just tried taking the Humax out of the loop as you suggested - unplugging the input and output RF cables from the Humax, coupling them and sending the output to the TV. The signal was fine on the TV (93%). So the signal is being lost between the RF input and RF output on the Humax. Maybe tomorrow I should dig the old Humax out of the loft and see whether the RF signal is OK on that.
I think it was the fan connector (i.e. on the motherboard) rather than the fan itself which was broken on the old Humax. IIRC I got hold of a new replacement fan and that didn't work, but it worked in the new Humax that I'd picked up on eBay. So I stored the old Humax in the loft as a future organ donor.

 

[everthewatcher]

The Humax was powered on when I tried it, so presumably would have been passing the RF signal through. So the signal is being lost between the RF input and RF output on the Humax.

Assuming no more assumptions it looks like we may have the answer. Makes me feel a bit better after screwing up elsewhere.

It wouldn't the first time an RF socket has been broken on a tuner can and I did it myself on a Sony ST-SB920 tuner last year. It's easy enough to fix if you know what you're doing but if not get someone else who knows which end of a soldering iron to hold to have a look at it.

That said, I'm not going to open an HDR to see but it should be possible to pop off the side of the 'in' tuner shielding can without taking out the PCB - I'm assuming it's the V1 with twin tuner modules and side-by-side RF connectors.

 

[Black Hole]

I think it was the fan connector (i.e. on the motherboard) rather than the fan itself which was broken on the old Humax. IIRC I got hold of a new replacement fan and that didn't work, but it worked in the new Humax that I'd picked up on eBay. So I stored the old Humax in the loft as a future organ donor.

Fair enough. If the connector itself is physically broken, that might be repairable. On the other hand it might be the driver that is broken.

unplugging the input and output RF cables from the Humax, coupling them and sending the output to the TV. The signal was fine on the TV (93%). So the signal is being lost between the RF input and RF output on the Humax.

That seems to be a reasonable conclusion. I don't think it is likely to be responsible for a decrease in signal rather than a total loss of signal (for the Humax) though. Take a look in the pass-through socket and see if the centre pin is still there.

What you could do with the broken-fan unit is run it up and see whether the reported signal strength is similar.

 

[everthewatcher]

Take a look in the pass-through socket and see if the centre pin is still there.

To fit the symptoms it would have to be the RF in, not the RF out/pass through.

 

[Ian Manning]

To fit the symptoms it would have to be the RF in, not the RF out/pass through.

The centre pin on the Humax RF out is still there in any case. Time to dig around in the loft.....

 

[Black Hole]

To fit the symptoms it would have to be the RF in, not the RF out/pass through.

Strange idea. The Humax is reporting some signal (not no signal), but the TV reports no signal from the pass-through... so what symptoms are you thinking of?

 

[everthewatcher]

Strange idea. The Humax is reporting some signal (not no signal), but the TV reports no signal from the pass-through... so what symptoms are you thinking of?

HDR reporting <<40% signal with dropouts, TV reporting >90% on the same connection, but dropping to zero when connected via the HDR RF Out.

The OP says "My T2 is increasingly losing its TV signal completely (i.e. a blank screen with the "no signal" message), or the picture is breaking up badly" so presumably it previously was fine although we have no prior signal strength measurements to help here..

The OP also says "My TV uses the same RF feed, but doesn't struggle as badly as the Humax - i.e. the live TV picture never breaks up or disappears" so clearly wasn't connected via the RF Out on the HDR.

Based on this it does look as if the issue could be with the RF In connection on the HDR. If the connection was disturbed some time just before the problem started then this could back this up.

 

[/df]

... On the HDR-FOX, if you press "OK" while tuned to any particular service then press "i" (info), you will get a pop-up reporting the transmission characteristics for that service - of particular interest is the UHF channel number. ...

And on the HD-Fox too, but maybe you weren't excluding that. News to me, anyway.

 

[Trev]

Why are 'we' using the word "transponder" reference terrestrial TV? That is a satellite term.

 

[everthewatcher]

Why are 'we' using the word "transponder" reference terrestrial TV? That is a satellite term.

Presumably the Foxsat came first and there was no reason to change it as the customer wasn't going to see it.

 

[prpr]

The Humax will need a better signal than your TV as it is a recorder

Why does a recorder need a better signal than a TV? They both have to demodulate the signal to get a transport stream. Explain.

 

[Black Hole]

HDR reporting <<40% signal with dropouts, TV reporting >90% on the same connection, but dropping to zero when connected via the HDR RF Out.

Therefore it's the RF Out (pass-through) that's broken. If it was only the RF Input that had somehow degraded (without complete LoS), the RF Out would have a similar signal strength as the HDR-FOX is reporting. Anyway, switching in the old unit (with non-functioning fan) temporarily should prove that one way or the other.

The OP says "My T2 is increasingly losing its TV signal completely (i.e. a blank screen with the "no signal" message), or the picture is breaking up badly" so presumably it previously was fine although we have no prior signal strength measurements to help here..

We have no idea what environmental factors are involved. It is entirely possible the TV (which looks very new) has a new technology tuner with greater sensitivity and noise rejection. It is possible the 700MHz clearance programme has shifted the channels in use down to the marginal reception of the existing aerial group, and/or the propagation path has acquired new obstructions, and/or the aerial/cable is degrading. That's where I put my money (and a broken pass-through).

And on the HD-Fox too, but maybe you weren't excluding that. News to me, anyway.

You're right, I wasn't excluding the HD-FOX (but this conversation is about HDR-FOX). In a more general information post I would have specified HD/HDR-FOX.

Why are 'we' using the word "transponder" reference terrestrial TV? That is a satellite term.

I'm not, that's for sure. I think the confusion might come from the OP's dogged use of the service menu tuner test (a lot more fiddly than the Signal Detection menu) which only reports the frequencies (similar to satellite). It is conventional to use channel numbers for UHF TV.

Why do satellite TV circles use "transponder" at all? They're not transponders from the user's point of view (or even a technical point of view) - I take "transponder" as meaning a device which responds to a received command by transmitting a response which is not the same as the stimulus (eg an IFF transponder on aircraft, which emits a signature in response to a query, or even a sonic key fob locator). Something which simply passes on what it receives is a repeater.