Freesat: Horizontal polarity break-up issues. Advice needed please!


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May 8, 2006
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I’m having no end of grief with frequent break-up on horizontal channels on Freesat, and I’d appreciate some advice from other forum members as to what the issue might be, or ways to tackle it. The post is a bit on the long side, sorry.

First, a bit of background. I have distribution system installed at my home, which routes DTV, DSAT, DAB and FM to all rooms. The system, apart from the 80cm dish, is completely Triax-based -- LNB, switch, faceplates, etc. The system was installed in 2008, with the original Antiference switch replaced for a Triax several years later. (Can’t recall why, offhand.) The LNB and faceplates are those original installed, other than for upgrades (see below). The switch lives in my home’s loft. I also have standalone dish feeding the front room only, again using Triax faceplates for in-room connections. The second dish was originally planned to get German DSAT, as I worked for a time at a Swiss bank and wanted to improve my German language skills. It never happened!

Late last year, the distribution system connections were re-jigged slightly to allow a feed into a newly-built extension, and to provide a third feed in the front room.

In January, the standalone dish, which was pretty knackered, was replaced with an 80cm Technomate dish and Labgear hybrid LNB -- 2 ports for ready for an Arris box, which I’ll buy once the current audio problems are fixed, and 3 Freesat legacy ports. Four of the connections used existing cables, with one new port. Room side connections are Triax F-connector faceplates, as previously mentioned. WF100 grade or better cables are in use for all external connections. The installer is a guy that I’ve used for years and he always does a cracking job. Anyway, the evening after the dish install, connecting my LG TV to the new port on the standalone dish, I started getting break-up on H & V channels. After some discussion with my installer the next day (and thinking about the well-discussed LG Freesat TV issues, a thread elsewhere in this forum) I agreed to try a Manhattan SX receiver and connected it to the port previously used by the LG. For the first 10 days or so things looked good, pointing to the LG, then one Saturday evening, watching BBC4HD we experienced 18 break-ups in less than 2 hours.

My installer came back to take a look. In his experience, he’d never had a faulty LNB from new. On checking the LNB connections, he found one F-connector to be a bit iffy, but swapped the LNB for a Sky-branded one in any case, which he prefers using. Things looked fine for a while, then the break-up started again. I poked around on Lyngsat and noted that all of the channels having break-up were H polarity. V polarity seemed fine, so I decided to start using the distribution system’s new port for the LG, whilst waiting for my installer guy to call again. Yet again, I started seeing break-up on H polarity, but not V. Substituting the Manhattan SX also showed break-up.

My installer called on Monday to check things out again. On the standalone dish, his meter showed 100% SS/SQ on the Freesat ports, and about 70% on the ports ready for the Arris. Checking-out the new distribution port, he got 100% again. He also used his meter to run cable checks, and all got a clean bill of health. Unfortunately, he doesn’t have a meter that can check individual frequencies.

As a test, yesterday evening, using the distribution system, we watched This Is Going To Hurt on BBC1HD Wales (H) via the Manhattan, whilst recording it on my Humax 1100S Freesat PVR. I noticed an audio drop-out live at about 22m in, which was also trapped by the Humax. By comparison, the recording made on my Panasonic Freeview PVR, again connected to the distribution system, aerial pointing to Emley Moor, was glitch-free.

When the installer comes back from his honeymoon in a couple of weeks time, he plans to install a Sky minidish on my home’s chimney, so that he can split the standalone dish's functions. In his plan, the minidish will feed only the ports for the Arris, and the hybrid LNB will be replaced with a legacy unit. His rationale is that in his experience, he has come across a few cases of interference between the port types. I think that the roles should be reversed. I’m doubtful that this will make any difference. However, at present, both 80cm dishes are stacked above one another, so having a dish at a different physical location might avoid some sort of very local interference problem.

Looking back, I only really started using Freesat in anger after the Bilsdale Freeview TX fire last year. Overall, picture quality does seem better on Freesat, and I’m keen to continue using it, especially as the impacts of COM7 on Freeview are yet to come. However, with such frequent glitching, more than I get on Freeview, I’m beginning to wonder. My installer does occasionally notice the odd glitch on his SkyQ system, and I know from past experience (with rubbish Freeview signal levels from Emley Moor and the temporary Bilsdale mast) that I get glitches here and there. Same deal streaming. It’s not a perfect world that we live in. As an example, if my wife watches ITVBe on Freeview between 1800-2000 she will she some glitches. That problem disappeared some years ago, but came back after the Bilsdale mast fire. Oddly, we see it if we use Emley Moor too. There’s some weirdness going on somewhere, not helped by the fact that my home, a bungalow, is at the bottom of a hill.

About a 5 minute walk away from my home there is a Morrisons store, and behind that the Taylors of Harrogate plant, otherwise it’s just normal housing stock, nothing fancy. I did wonder if there was some sort of interference coming from Morrisons or Taylors, but it’s so random, I can't see how. My installer thinks it unlikely, given that it’s only hitting H polarity (thus far!). I also considered an electrically noisy appliance in my home. It’s possible, perhaps, but I think unlikely, again given the specific problem.

Both dishes have a clear line of sight. There is a tree in line with the dishes, but it has no impact. It’s currently clear of any leaves, and has recently been trimmed, so I don’t think it relevant. If it were, I would expect both H & V polarities to be impacted, not just H.

All of my kit in the front room is connected to a Sounds Fantastic 8-way power strip, which is supposed to be full of filters, and it uses shielded mains cable. All of my flyleads are made from CT100 cable with good quality plugs. Kit is connected via screened mains leads where possible, and all mains cabling is fitted with ferrite chokes. Mains, signal and HDMI cables are kept well apart. The Triax distribution unit in the loft is on its own circuit breaker, with only two smoke detectors connected to the mains with it. It’s plugged in to a Belkin surge suppressor.

I can’t think of anything else to try, save perhaps fitting some ferrite chokes to the flyleads. It makes no sense to me that both DSAT systems have the problem. There are some common denominators of course -- the mains power strip, LG TV and so on, but I don’t have the luxury of being able to swap those about at present.

Does anyone have any suggestions or ideas? I’m stumped. My ultimate fallback position would be to junk Freesat, bite the bullet and sign-up for Virgin Media cable box, which I really don’t want to do.

I'd probably try some power pass attenuators first. Too much signal can result in overload and it was one of the 'cures' for the Panasonic FEC issue?

I'd also ensure the wideband ports are terminated with a 75 ohm resistor in a F-plug; in case they are 'live' with power in to the legacy ports and causing an issue somehow.
@Rodders53: thanks for the reply, I’ll grab some f-plug terminators for the wideband ports. I asked my installer about having too much signal and he said in his experience he’d never come across a need to attenuate satellite signals. It was something that I recall from the thread about the LG TV satellite issues.

For the 75-ohm terminators I was thinking along the lines of these: Amazon product ASIN B07GVWNQQC There’s similar on the likes of eBay.

Should I also use these on any unused satellite ports on the distribution system? There are a few rooms that currently have unused DSAT and DTT outlets. Presumably, unused DTT connections wouldn’t need termination.

As for the power pass attenuators would I use these only on the standalone dish, or distribution outlets too? Could you point me in the right direction for those please? Regardless of my installer says, I‘m certainly prepared to try what you suggest, because if they work, then that’s a cheap win.
Amazon seems expensive for them Terminators 75 Ohm - A.T.V. Poles, Brackets, Clamps & Aerials
CPC sell packs of 10 for under £2 but they have a small order surcharge of £5.
They also sell a range of suitable DC pass attenuators pass attenuator so...

Terminator use is not common on domestic installs but is certainly best practice on UHF as much as Sat: Splitters, amps and diplexers - A.T.V. Poles, Brackets, Clamps & Aerials

They may have no bearing or effect in your case though, as many installs get away without using them.

Use the freesat devices' metering on a selection of the 'problem' pixellating channels to see if there's any pattern in the reported figures for S and Q?
Hybrid LNBs especially sky branded ones, as far as I know are only available matched for the sky elliptical dish wider than tall. Using one on an 80cm round dish may well cause a mismatch and cause problems.
@Rodders53 : the glitching is so random that by the time I’ve got to the onboard metering I’ve missed it. It was one of the things that I’ve tried. When I have checked the metering it all looked stable.

@winston2010 : point taken about the LNB, but my installer tells me that he’s fitted such combos. before without issue. The LNB is not one of the elliptical looking ones. It looked very similar to the Labgear LNB that was swapped out. It did need a good wrap of amalgamating tape around its neck to keep it securely locked in the arm’s collar though.

I will go ahead and order some terminators for DSAT and DTV. Pity that ATV don’t offer male and female terminators though, as the Triax plates have ports fir DSAT, DTT and DAB/FM. I will need to get creative with some adapters!
I will go ahead and order some terminators for DSAT and DTV. Pity that ATV don’t offer male and female terminators though, as the Triax plates have ports fir DSAT, DTT and DAB/FM. I will need to get creative with some adapters!
The filtered plate will offer terminated 75 ohms to the incoming cable at least. 75 ohm resistors is all that is in the plugs if you want to make your own 1/4 W or 1/2W - pack of 50 a £1.10 from CPC.

To be honest I doubt terminators will cure anything; but it's a relatively inexpensive thing to try.

Equally likely is something coming in on the mains. Filtered power strips do very little in my opinion. Any thermostat or timer switch on a motor or big load (central heating, fridge, freezer, oven, hob, microwave) could cause an issue. Possibly yours, possibly a neighbour.
Possibly even fat pigeons obscuring the dish sufficiently to cause the glitch.
Why H only affected is another question, though...
@Rodders53 : I'm just about to order some 75 ohm terminators from ATV. It's worth a try. I could have a faceplate picking something up somewhere. As you say, if I don't try, I'll never know. When the Triax switch was installed I kept the old Antiference Isys unit as a backup, as it was still working, and I found some f-connector terminators in the box which I've fitted to the spare ports on the standalone dish. I recall buying these to fit to the Isys switch, which interestingly has a label on the front stating that all unused ports must be terminated.

The mains side of things did cross my mind. Generally speaking, when we watch TV it's in the evenings, so the only appliances that could be in the mix would be fridges, freezers and the CH boiler, which was replaced last year. I'm not ruling out something mains borne, but again, why only H polarity? That's the bit that makes no sense to me. I am going to investigate the mains side of things a bit more, but if it was mains based I would expect its effects to be more widespread than it currently is. It's possible that rubbish is being picked-up by one of my a/v units and is then pushed around the kit.

I'm also ordering a signal attenuator to try out on my LG TV. Another long shot though, I suspect. The planned split of LNB duties might help, or it might come to nothing. No idea until my installer tries it. My long-suffering wife would rather I get rid of the dishes on the side of the house. If relocating a dish to the chimney clears the issue, even if it's only for regular Freesat, I may have to concede defeat. Oh dear.

I really hate problems like this!

@winston2010 : I owe you an apology. I took another look at the Sky LNB that's fitted to the standalone dish. It does have an elliptical shape to it. I'll mention your concerns to my installer when I next see him.

I'll report back once I've fitted the terminators. Thanks for the suggestions and advice thus far. If you do think of anything else that I can try, please shout!
Well, I now have 75 ohm terminators fitted to every spare outlet on both the standalone dish and distribution system. On Sunday evening, watching Call The Midwife in BBC1HD wales (H) on my LG, connected to the standalone dish, I reckon that I saw a glitch, but my wife didn’t. I was sure that the picture froze briefly whilst the audio continued. Hmmm. More monitoring this week.

I got the terminators from ATV Aerials in Sheffield (thanks fir the suggestion @Rodders53). I’ve used ATV before but called them for a chat to sort out some adapters to go with the terminators. Anyway, Paul at the shop gave me a discount on the postage. I know that I could have got the bits cheaper elsewhere, but I’m a firm believer in supporting businesses where you can pick up the ‘phone and actually talk to a professional and get some advice.

I’ve also fitted a few more ferrite chokes to some mains cables, but have yet to fit them to any signal cables. One change at a time. Ferrite chokes definitely work in certain situations, I speak from experience, but whether they’ll help here I have no idea. Anyway, as I have a load of them (anyone wanna buy a few from me? :D) it will be a cheap thing to try.

I’m also toying with idea of a mains conditioner. I used an Isotek unit sone years ago in anger and it really sorted a mains interference problem that I was having with some a/v gear when I was living in a flat. I just need to decide which organ to sell to fund one. Ah, the joys of intermittent faults.
Sigh. After a week or so of glitch free viewing on my LG TV using the standalone dish, I managed to get a glitch on both an H and V channel! Gah. I do think that the terminators have improved things though. I’ll move the LG to the distribution system and see what happens. I suppose that it comes down to frequency, as in how often I see glitches, that will determine if I stick with Freesat.
I've been meaning to update this thread for a while now. Too many other things going on.

Anyway, on the plus side, fitting 75 ohm terminators to all of the unused outlets on the distribution system has apparently fixed the DSAT brake-up, at least to the point where we haven't noticed any break-up on either H or V polarity stuff that we've either watched live or has been recorded by my Humax HDR1100S PVR. We've also noticed a reduction in break-up on Freeview too. All that I can think of is that perhaps one of the wall plates is marginal in some way, and is picking-up interference from somewhere. I did also make sure that all signal cables were well separated and I fitted a couple of ferrite chokes to some of the more 'obvious' mains cables.

Unfortunately, not quite the same story on the standalone dish. Fitting terminators to the unused outlets may have reduced the problem a little, but it's hard to tell. The next step, when my friendly satellite installer gets back from his honeymoon, is to add a third dish (don't mention this to my local council!), so that the existing dish can have an LNB purely for Freesat connections, the new dish having a dedicated Wideband LNB. That's about all that's left to try and isolate the problem. I might hold fire on the dish split a while longer in the vain hope that Arris will finally deliver software for the Freesat PVR that addresses the lack of 5.1 audio. I am curious to see if I get break-up on signals using the Wideband part of the existing dual-type LNB. The software update is supposedly due this sometime this month. I'm not up for paying well north of £200 for a PVR with such a serious flaw in its software.

Onwards and upwards ...
I realise this thread is an old one, but I've been having what I might class as break up on my system recently. We refer to it as a stutter, the image seems to stop then start again.
Ours occurred when we were using all the ports on our Sky Hybrid LNB.
By disconnecting the third box we now get perfect pictures on our Arris 4K and our Humax HDR 1000.
Just thought I'd mention it.
Thanks for the reply. I still get intermittent break-up even though the LNB has been swapped for a standard type. The stutter issue that you mention is apparently a known issue with some early hybrid LNBs, so my satellite installer was telling me. That's what he thought the issue might be, but in my case not so.
Thanks for the reply. I still get intermittent break-up even though the LNB has been swapped for a standard type. The stutter issue that you mention is apparently a known issue with some early hybrid LNBs, so my satellite installer was telling me. That's what he thought the issue might be, but in my case not so.
If it was a known issue it would be all over these and other forums.

Most likely causes dish alignment (including LNB skew) or dish shading.
Not necessarily. It depends on LNB usage, I think.

I trust my installer, and I've been using him for years. He told me about half a dozen installations that he'd been to that had had similar problems to mine, some of the jobs not having been originally installed by him. I have no idea if what he's telling is correct, but the work that he's done at my home has greatly reduced the break-up issues. Could be a duff batch of LNBs. Who knows?
Most likely causes dish alignment (including LNB skew) or dish shading.
I had already tried both adjustments you mentioned, but it made no difference. As soon as I disconnected the third box, all was well. To prove the point (to myself) I reconnected the third box and the stutter instantly returned. I could have messed about and changed which box was connected to each port to see if there was a pattern but the third box is only a "spare" .
My suspicion would be:
added psu ripple to lnb (via internal diodes) = extra noise from multiple boxes connected
ground loop type effects causing similar

Proving either would not be a simple task.

IIRC some relatively early $ky boxes were renowned for causing noisy DC issues via lnbs?

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