Picture break up on Aura

Ooh. Oooohh. Just tried putting the variable attenuator in line. As I wound it down (up?) The strength on C21 dropped from about 98 to 94 but then the quality started to drop dramatically.
On C25 the quality fell off even quicker and it lost signal on the programme.

So either signal strength isn't the issue or this attenuator is damaging the signal somehow (or is having strange interactions with the other equipment in the line).
I see the planned works are continuing this week, so I think for now we'll just have to wait until they are done and see if the problems persist after that.
 
After the amp. This was down by the box.
The coax goes: aerial - amp in loft - psu in room - passive splitter < Aura + TV.
I tried the attenuator on the input to the splitter. That and the box itself are the only plug connections - the PSU, amp and of course aerial are all screw and clamp types, so difficult to insert a coax device in line.

Unless it's failing I doubt the amp is doing anything strange. It's been working fine with this aerial, and until recently the FOX boxes, for many years. The main mux powers haven't changed either, being 200kW since DSO.

I'm wondering if this 'engineering work' has been going on for a while and is actually the cause of what SWMBO has reported as being 'ages'. She is prone to mis-remembering and exaggeration. It's frustrating that they don't give any likely end date - they may just keep repeating the same thing every week forever as a short of get-out-of-jail card.
 
Ooh. Oooohh. Just tried putting the variable attenuator in line. As I wound it down (up?) The strength on C21 dropped from about 98 to 94 but then the quality started to drop dramatically.
On C25 the quality fell off even quicker and it lost signal on the programme.
I have used an attenuator with other Humax boxes without problem but not needed to try on an Aura. When did you buy this Aura? There were some problems with early production Aura that was traced to an out of tolerance component in the tuning circuitry and Humax swapped out the boxes.
 
It's been working fine with this aerial, and until recently the FOX boxes, for many years.
It's your aerial. Almost guaranteed. You said it's outside. It's got an odd frequency response. How old is it?
The solution is to replace it all, and change any re-used cables (internal ones only) with non-F ends to F ends. It'll save grief in the longer run.
 
Just for fun and 'cos my box of fixed metal barrelled attenuators was to hand I added 6dB, 12 dB and 18 dB, in turn, between the aerial feed and my -T2. In addition to the 4 dB splitter loss to feed it and my OLED TV.
All measurements via the Humax UI signal condition. {My previous post numbers were from the WebIF screen which is stored at some point, after a retune?, and never changes in real time}.

Most (all) the S levels were varying a little by a digit or so +/- the number I recorded. But that's no big issue.

21: 72 -> 67 -> 46 -> 0
24: 75 -> 68 -> 53 -> 50 at a steady 100% Quality!
27: 72 -> 66 -> 49^ -> 0 (^ at 90-100% Q)
33: 74 -> 67 -> 53 -> 52 at 10-30% Quality
36: 74 -> 66 -> 51* -> 0 (* at 50% Q)
48: 74 -> 68 -> 53 -> 49 at 30-40% Q.

I never bothered to look at the pictures with any attenuators in circuit.
I did see the 66<->55 signal level flip-flopping that was mentioned and I suspect another oddity may occur at low signal levels (possibly).

I really think it must be worth the pain in measuring all signals with both Aura and your -T2 including the signal direct (no splitter) so circa 4 dB higher still. If it's receiver overload then any breakup should be worse without the splitter loss.

My Panny OLED reports 100% S on all but ch 48 where it's 99%. Attenuating by 18 dB gave some reduction of S to 94% but Q was low with high BERs (but not as much breakup as I expected). The HD mux 21 was 'blank' and 0 Q with 18dB in.

The Planned Works description, to me, suggest switching breaks to/from the aerial combiners and/or main/reserve antennas. These are not as seamless as other maintenance work (A/B transmitters, A/B fibre feeds switching) would be. It may be for mast painting work, or other up-mast maintenance checks or repairs that will be weather dependent.
Similar works are going on at many other sites - including my own.
 
My previous post numbers were from the WebIF screen which is stored at some point, after a retune?, and never changes in real time
Correct. That's how the Humax firmware does it internally, the WebIF merely reports what's stored in the database.
 
It's your aerial. Almost guaranteed. You said it's outside. It's got an odd frequency response. How old is it?
It's an XB16A, not cheap and only 7 or 8 years old. The cable was new at the same time. (If I need to junk all that I'd probably replace it with another satellite system and sell the Aura.)
 
Just to backfill some info ... I was in the loft just now getting a suitcase and had a look at the amp. It's a WB22/2 which has an 18db gain. (It's also a splitter with two outputs.) There's no adjustability visible on/in it or mentioned on the website.

I'd forgotten about the second output. It feeds an outlet in a bedroom that isn't currently used, but might be in future. Given that, and also that I suspect losing 18db will poleaxe even the main muxes, I think it will have to stay. An experiment would be nice but the way the amp and its PSU are wired into the coax it would be a real pita job.
 
https://www.aerialsandtv.com/product/xb16a-aerial is a mahoosive antenna! Not the greatest gain at 21 cf the rest of Band A, but nevertheless higher than any decent quality alternatives. Likely in a fringe location there will be diffracted signals over hills/ridges rather than line of sight and 'standing waves' that needs careful antenna positioning to get even signal levels across the band?

What does Wolfbane predict your field strength to be? http://www.wolfbane.net/ (click the UK digital TV predictor link) Just for the fun of some gain/loss calculations.

https://www.fringeelectronics.co.uk/wb22range.html is the amp and Fringe state that it may need filtering from mobile (4G mentioned from the 800 MHz clearance, but now it will be a 21-48 bandpass following the 700 MHz clearance). While it may be a low likelihood of mobile interference (the aerial has good rejection above ch 45/46) it's worth checking if you might be affected? https://restoretv.uk/

A filter is fairly cheap https://cpc.farnell.com/blake-uk/prolte5g700/5g-filter/dp/AP03775 but if you are affected Restore TV will supply one free to you. It will have some insertion loss (but less than 1 dB). It's possible, though, that some unwanted signals are picked up, not by the aerial, but by the amplifier/cabling if it's not in a fully shielded metal enclosure? (The Fringe pics aren't clear.)

However if the bedroom outlet from the Fringe masthead has nothing attached it would be worth fitting a 'terminator' (75 ohm resistor between centre pin and outer screen). A TV set tuner or even a 2-way splitter will have the same terminating effect. https://www.aerialsandtv.com/knowledge/splitters-amps-and-diplexers#amplifier-terminators
The 18 dB outlet signal level is the same as the 'Full' output Justin mentions on the Proception 8+Full distribution amplifiers he sells.
 
An experiment would be nice but the way the amp and its PSU are wired into the coax it would be a real pita job
It's just a matter of cutting the cables, fitting some F connector and connectig them together with F barrels. Then you can barrel out the amp. too. Same with the PSU.
Roughly where are you and is the path clear to Rowridge? Sounds like you have too much gain, if the aerial really is OK. But you will only know by getting the amp/PSU out of circuit.
Their security certificate has expired (this afternoon!).
if you are affected Restore TV will supply one free to you. It will have some insertion loss (but less than 1 dB).
I couldn't be bothered with all that and bought one for a handful of pound notes (along with some F attenuators, for test purposes). I think it made a difference of 1, at most, on all the strength readings on my T2, which was better than I was expecting.
 
The -T2 readings for the two muxes measured to date don't suggest overload to me. Especially as the Aura lost signal with the smallest attenuation added.
There's a chance of interference under enhanced propagation if such a large array if pointing Continent-wards. The Vp signals are more immune to the Hp transmitter source on the continent (and ROW is directional to not interfere to them as much).

I'd recommend terminating that 18 dB masthead output, if it isn't already, and repeating measurements for all the mux frequencies before doing anything else, so they can be used as a baseline?
Ideally with both Humax PVRs.

Every connector introduces some insertion loss and potential for impedance mismatch (especially Belling Lee TV plugs and sockets). So can saddle clamp connections if they distort the cable significantly. Often such losses are usually unimportant, but baseline measurements will help identify any changes for better or worse when experimenting with things.

Location of this install would, indeed, be helpful. A very nearby shop, pub, school or church postcode would allow predictions to be run without identifying the exact address / dwelling (probably).

PS ATV's certificate seems OK this morning.
 
https://www.aerialsandtv.com/product/xb16a-aerial is a mahoosive antenna! Not the greatest gain at 21 cf the rest of Band A, but nevertheless higher than any decent quality alternatives. Likely in a fringe location there will be diffracted signals over hills/ridges rather than line of sight and 'standing waves' that needs careful antenna positioning to get even signal levels across the band?
Yes, it's a big bugger. Because of the difference in powers across the MUXes it's always been a bit of a struggle to get reliable operation of the minor ones.

What does Wolfbane predict your field strength to be? http://www.wolfbane.net/ (click the UK digital TV predictor link) Just for the fun of some gain/loss calculations.
Like all of them it suggests we shouldn't need anything special. I suspect our particular location is 'difficult' as we have actual ground between us and line-of-sight, and that ground has many trees and buildings on it.
You can tell it's a strange area as there is every permutation of aerial type, direction and orientation, some of which probably don't even work reliably (my neighbour behind, which is the direction my aerial is facing, is a case in point). There are a lot of satellite dishes.

https://www.fringeelectronics.co.uk/wb22range.html is the amp and Fringe state that it may need filtering from mobile (4G mentioned from the 800 MHz clearance, but now it will be a 21-48 bandpass following the 700 MHz clearance). While it may be a low likelihood of mobile interference (the aerial has good rejection above ch 45/46) it's worth checking if you might be affected? https://restoretv.uk/
I think it is at least somewhat protected as I used to have two aerials combined via a hi-lo pass device. I think the divide is at channel 38. (Edit. Just found the web page I documented this exercise on: Adding group E to an A to get channels 55 &56 ) The XB16A is the lo-band and there was a Yagi I think for the hi-band to get ch 55 &56. After removing the high band aerial I deliberately left the combiner in the line to act as a filter since it will only pass group A (or lower) frequencies.

However if the bedroom outlet from the Fringe masthead has nothing attached it would be worth fitting a 'terminator' (75 ohm resistor between centre pin and outer screen). A TV set tuner or even a 2-way splitter will have the same terminating effect.
That's a thought though I suspect it's not related as it's been like that most of the time we've been in the house.

There's a chance of interference under enhanced propagation if such a large array if pointing Continent-wards. The Vp signals are more immune to the Hp transmitter source on the continent (and ROW is directional to not interfere to them as much).
Yes, I think we have had occasional problems in certain weather conditions, but then it wasn't just us. Now I see that V gives us 200kW on all muxes I will flip the aerial on it's side sometime (when we get some summer again) assuming all the bolts haven't seized up.
 
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It's just a matter of cutting the cables, fitting some F connector and connectig them together with F barrels. Then you can barrel out the amp. too. Same with the PSU.
That'd cost me about £30 in F bits and introduce a bunch more connections in line.

Sounds like you have too much gain
Given that on (one of) the most powerful muxes the FOX was only reporting about 80 strength that seems unlikely. It's always been a struggle to get the lower power muxes reliably.

I will flip the aerial, per above post, and wait till this engineering work is done before monitoring the picture quality and possibly doing anything more intrusive.
 
Rowridge isn't listed in the engineering works this week, so we'll see what happens.
Hoping to change the aerial to V on Thursday if the weather is as predicted.
 
the FOX was only reporting about 80 strength
:eek: Only? That's a lot in my book (I don't even get that with a 10 dB amplifier in circuit). Of course just using the strength figure is no useful measure of being able to demodulate. It's C/N (carrier/noise) that is important and it doesn't tell you N, so reporting C (aka strength here) isn't that helpful in the grand scheme. It's perfectly possible to decode reliably as low as strength 30 and a bit lower.
 
Only? That's a lot in my book
The only is in comparison to the Aura which was bouncing off 100.

The problem I've had since moving here isn't the main muxes but the secondary ones, and those two now extinct COMs, as they are at lower powers and sometimes dropped into flaky territory. I'm hoping that changing to vertical so all the muxes are at the higher power will make life a bit easier.
 
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