Terrestrial picture randomly breaking up - reboot receiver fixes it

[Stuey2017a]

As an update, I performed a fresh install (latest build) and manual scan (as usual) and last more than 20 hours but then all my HD channels have broken up .. and again the reboot fixed the issue.

 

[Stuey2017a]

Issue still persisting .. today all channels were breakign up (and nothing had been recording or had recorded in over 12+ hours) .. will call WoS.

 

[goRt]

Issue still persisting .. today all channels were breakign up (and nothing had been recording or had recorded in over 12+ hours) .. will call WoS.

Bizzarely today is the first time since trying atv last week that I've been able to get a stable picture on any build.
Last night's atv won't boot.
Vic .027 has been stable after a few manual scans for about 3 hours now whereas normally tuner a fails within minutes!

I've disabled ABM auto scans.

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[Stuey2017a]

Heard back from WoS; they mention:

First thing I'd advise to do is try using an attenuator. You may have high signal causing signal flood. They're low cost and sounds like this will resolve your issue.
Doubtful that low signal is causing this from your report.​

Has anyone heard of, or experienced similar issues where an attenuator resolved the issue? In addition, anyone got a link of the one I need to by for the Rf/aerial?

 

[twol]

Attenuator‘s are used on cable & sat tuners for same reason... in fact you can even buy multiswitches with them on to handle multiple sats.... I am sure somebody will provide a link to your requirement.

 

[goRt]

Heard back from WoS; they mention:

First thing I'd advise to do is try using an attenuator. You may have high signal causing signal flood. They're low cost and sounds like this will resolve your issue.
Doubtful that low signal is causing this from your report.​

Has anyone heard of, or experienced similar issues where an attenuator resolved the issue? In addition, anyone got a link of the one I need to by for the Rf/aerial?

I've had a quick read up on freeview page and should get a signal strength at a max of 75 - mine's at 87, there's an attenuator in maplin for a fiver, I'll grab one tomorrow as turner a has gone again after about 4 hours.

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[Stuey2017a]

I've had a quick read up on freeview page and should get a signal strength at a max of 75 - mine's at 87, there's an attenuator in maplin for a fiver, I'll grab one tomorrow as turner a has gone again after about 4 hours.

Hi goRt, you got a link to that Freeview page mentioning the signal strength (mine is 99% - I thought the higher the better!!??) and also you got a link to the attenuator you're buying in maplins? Not sure which one to go for, if I need a variable one, etc. I will have a browse as no maplin or similar shop near me, so will buy online. Also let us know how you get on .. hopefully this will resolve the issue..

As a side, could anyone explain to me if it is the high signal causing signal flood, how come this only affected the Octagon SF4008 and not my old/previous Humax PVR or in fact the tv connected direct?

 

[Stuey2017a]

ah found the FreeView (signal strength) page: https://ukfree.tv/article/1107051892/Freeview_signals_too_much_of_a_good_thing_is_bad_f

 

[goRt]

Hi goRt, you got a link to that Freeview page mentioning the signal strength (mine is 99% - I thought the higher the better!!??) and also you got a link to the attenuator you're buying in maplins? Not sure which one to go for, if I need a variable one, etc. I will have a browse as no maplin or similar shop near me, so will buy online. Also let us know how you get on .. hopefully this will resolve the issue..

As a side, could anyone explain to me if it is the high signal causing signal flood, how come this only affected the Octagon SF4008 and not my old/previous Humax PVR or in fact the tv connected direct?

I was going to get this:

https://www.maplin.co.uk/p/aerial-attenuator-6db-bw59p but could be persuaded to get a variable one

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[ccs]

..I'd get a variable one.

 

[twol]

As a side, could anyone explain to me if it is the high signal causing signal flood, how come this only affected the Octagon SF4008 and not my old/previous Humax PVR or in fact the tv connected direct?

Depends on the tuner in the receiver and sensitivity .... and the drivers written for the receiver

 

[goRt]

..I'd get a variable one.

Bingo

https://www.toolstation.com/shop/p86843?table=no

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[ccs]

Bingo

https://www.toolstation.com/shop/p86843?table=no

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Just make sure you get the right connectors.

 

[goRt]

Just make sure you get the right connectors.

Was just going to post that :-(

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[Stuey2017a]

If it helps, had an email off WoS this morning pointing me to this (which I have already purchased!):

http://www.ebay.co.uk/itm/Plug-In-C...d=390993822038&_trksid=p2385738.c100677.m4598

 

[adm]

Heard back from WoS; they mention:

First thing I'd advise to do is try using an attenuator. You may have high signal causing signal flood. They're low cost and sounds like this will resolve your issue.
Doubtful that low signal is causing this from your report.​

Has anyone heard of, or experienced similar issues where an attenuator resolved the issue? In addition, anyone got a link of the one I need to by for the Rf/aerial?

Counter intuitively too much signal can cause an over load of of the front end of a sensitive tuner (in a non-destructive way) and cause picture break-up. The simple cure is to put an in-line attenuation in the down-lead signal path or if you already have a aerial amplifier to remove it or turn down the gain (assuming the amp has that adjustment)

No two tuners from different manufactures are likely to have the same input sensitivity so plugging in the aerial cable to, say, a TV with a low sensitivity tuner may give perfect results whereas plugging the same cable into a box with a high sensitivity may cause picture breakup. Furthermore, with UK terrestrial the signal level you receive may vary during the day and/or as a result of high/low pressure weather systems. If your box is just on the limit of being overloaded you may have relatively long periods of good or bad reception depending on the time of day you are watching or recording.

Signal strength reported by boxes and TV should be regarded as just an arbitrary indication and the more important figure is the quality figure (some boxes may report a BER figure (bit error rate). Again, no two manufactures seem to report, or measure, signal strength in the same way. You cannot directly compare the signal strength reported by two different boxes or TVs apart from saying that seem to be indicating roughly the same. On some boxes I've owned a signal strength of 60%+ has produced reliable decoding/pictures whereas on others 80%+ is required. Many boxes cannot report more than 99% or 100% so give no indication that they may be over-loaded. A box reporting, say, 98% signal strength may be working within it's reliable input range but give the box 4x as much signal and it will still only report 99% or 100% signal strength but the front end may be over-loaded.

It's the quality figure that matters most which should ideally be 99 or 100% or a BER of 0.

In-line attenuators can be purchased quite cheaply. The sponsor has some with F connectors if you are using F connector fly-leads and F to Coax adapters to connect to a box's coax input
https://www.world-of-satellite.co.uk/satellite-and-terrestrial/attenuators

In-line attenuators with co-axial connections are available from many other sources including Ebay. Possibly buy a 6db and a 10db. They can be plugged together for 16db for a test but possibly not recommended as a final solution as this arrangemnt may not be mechanically robust when equipment is moved/dusted etc.

 

[Stuey2017a]

@adm - thanks for the excellent explanation, does clarify things alot more for me now .. and thanks for the link to the attenuator; I purchased a variable one in the end, so hopefully that resolves the issue (is there a method to using the variable one, I'm assuming I set it to the lowest setting and then try upping it until I go more than a few days with no breakups?) ..

 

[ccs]

Try adding the attenuator at its lowest setting when you start getting breakups, and see if you can clear them.

 

[Stuey2017a]

Try adding the attenuator at its lowest setting when you start getting breakups, and see if you can clear them.

Thanks ccs, will try that, difficultly I have is that I cannot replicate or predict when I get them; although do seem to happen after recording programs on a given channel.
Out of interest, as mentioned previously I do seem to get these on given Channels e.g. ITV4, BBC, is this indicative of such a signal/attenuator issue - where some channels frequency/signal seem ok and only affected on others?

 

[ccs]

I've got an unexplained terrestrial aerial problem at the moment.

Brand new aerial and cabling - signal/picture is absolutely fine on all mux's, until it rains.

Then just one mux completely fails - zero signal. All the others are 100% fine.

There are trees which could be an issue (they are due to be trimmed), but I can't see why just one mux should totally fail.