Hello

Looking for some clarification on what may be required for a new house regarding Terrestrial and Satellite setup.

There are four RG6 cables to both the Living Rm and Main Bedroom to facilitate Sky+. There are single RG6 feeds to three smaller viewing areas with a maximum 32" TV.

I was looking at a loft box and looking for a means to view both Sky+HD boxes from any TV and control too (via magic eye and app too). Will be fitting a loft aerial too (Log periodic most likely) to feed UHF Freeview signal into loft box and all TVs with a view to select Freeview or Sky feeds from any TV.

Would I need any special faceplates for the Sky+ rooms as there are just four cables hanging loose from the wall at both outlets? I am thinking if so, two sat, one TV out and an RF2 return.

Keep it simple: dish on the wall; two feeds off that direct to each room. Aerial outside if possible unless local planning laws or housing covenant strictly forbids it (better quality of signal more important than absolute strength), + masthead amp if local conditions require it. Feed signal down main lounge and in to Sky box RF input. Then RF2 out back up to the loft for central distribution of Freeview plus main box RF2 signal combined. Put that signal in to the loft box and add the magic eyes for each room.

If you absolutely can't have the aerial outside then get a proper aerial installer to fit it. You want someone with a meter who can check the best location in the loft. It's not always where you might expect. Beware too that wet roof tiles will knock the signal down by a further 3dB (50%) on the already reduced signal just from being in the loft.

Thanks Chris

I like the simplicity. I take it I could just use a combiner (SPC4) for the two RF2 return feeds to the single input on the Distribution Amp or is there a cheaper option open? By the example you've given I could get away with a simpler and cheaper loft box which sounds good.

Regarding the aerial, there is no chimney so the only place to locate the aerial would be below the line of the roof on a side wall (same side as the Sky dish). The roof is a square-based pyramid in design. It would be facing Divis transmitter which is a very strong signal in my area. I was considering purchasing a cheap meter and performing the install in the loft myself but maybe siting the aerial on the side wall would work if not the most ideal place?

If I go for loft installation, I have read Log Periodic work but any other options?

I see you mentioned a drop of 3dB for water on the roof, snow would be worse I presume.

The SPC4's work well: Independent control of two Sky boxes via the same Sky Eye/RF distribution system is a neat trick. I've used them in a few installs. I haven't come across a cheaper way of doing that.

I don't know what loft box you were considering, but you certainly you don't need to spend on one with any satellite inputs. Just make sure it passes the 12V to make the Sky eyes work. Whether or not you want or need FM and DAB inputs is another question to ask yourself before spending.

With aerials, height and unimpeded line of sight are the two primary considerations. If you can get those then you're laughing. There are mounts designed to go on the tiled roof of houses without chimneys. LINK. Alternatively the more common solution is a pair of wall brackets that clear the house eaves (T & K brackets) and then will take a tall pole. 10ft, 12ft and 16ft alloy masts are pretty widely available. They don't rust. If you need taller then 20ft steel is an option, but you might want to consider getting that painted before installation.

Log Periodics are brilliant. They're the only aerial with a flat enough response curve that you get very little signal strength variation from the bottom of the frequency range right through to the top. That's important because there's still more changes planned for the channel allocations as the Government sells off chunks of the TV and Radio spectrum for mobile communications. The plan is to push TV transmissions down to the lower part of the frequency spectrum. This is where all those "wideband, high gain" aerials suck. The Achilles Heel of Logs is their gain. They don't "magnify" the signal's power as much as a good Yagi does. But Yagis and those wideband high gain aerials are tuned to work best only in a narrow frequency band. The right Yagi might work brilliantly today, but if/when the channel allocation changes again in 2018 then the Yagi could end up being useless compared to the Log.

Pretty much all of my installs now are done now with Logs. Sometimes the signal is strong enough that the aerial is all I need. Other times I need to add a Masthead Amp to give enough gain because the signal area is weak. With a Log I know that for as long as we use the the DVB-T/T2 (Freeview) frequency spectrum then the aerial will give great results.

Those DIY meters...

It's difficult to write the next bit without it turning in to a training course. Trying to summarise several days CAI Aerial Installer course knowledge combined with 7 years field experience in a paragraph or two is impossible. So I'll just give you the headlines and then leave you to do a bit of research yourself.

I've seen far too many DIYers struggle with the cheap SLX/Labgear LED meters and the newer DVB-T Signal Finder needle meters. The two main problems are the meter range is too high and the graduations far too coarse for the meters to be much use. For most people their aerials don't generate enough signal to light more than the bottom of the meter's range, so they're hopeless as a direction finder. Beyond that, the meters only take an average reading of the signal strength. There's no indication of signal quality which is actually far more important. You'd be far better carting up a portable Freeview TV and using the signal quality guide off that than wasting your money on the DIY meters.

If you're in a really strong signal area then you'll probably get by more by good luck than good planning. Any losses from the roof (dry/wet/snow) won't be that significant. Buy a Log P, some WF100 cable (that's the good stuff. Don't cheap out with RG6 or - shudders - 'low loss coax') and some plugs which will be F type for most of your boxes and the eyes, and only an 'aerial' plug for the TV socket. Use a portable, go in the loft and see how you get on. Signal Quality should be 90-100% (or at least that's your aim). Signal strength will be fine at anything from 50-80%. If both are maxed out then buy a 0~20dB variable attenuator. You might find that you need to knock the signal strength down in order to get better signal quality.

Thanks for the comprehensive reply - appreciated.

The builder has put RG6 cabling in . I suppose the drops in the rooms and the connection to the Sky dish's LNBs could be changed (in the case of the Sky Dish cabling of four single runs) to avoid any corrosion? As Sky would be installing their equipment I presume they use WF100 to save me getting any?

Wasn't planning on using FM/DAB feeds just Freeview (HD) and Sky (direct and RF2 modulated) though will need to find a couple of Sky+HD RF2 convertors. Any recommendations for Loft boxes that will have aerial and RF2 return input with outputs for the 5 TV locations (incl. Sky+)?

Would like to try a loft install of the Log periodic and considering this although I have seen 4G versions with what I presume is some sort of bandpass filter arrangement but is this marketing?

TBH I wouldn't bother trying to find a loft box with a dedicated input for the RF2 returns separate to the regular aerial feed. Chances are that if you find one then it will also come with loads of other superfluous inputs (Sat, DAB, FM, CCTV etc) which you'll never use. Just keep it simple as I said in the first post, but integrate the SPC4 from the two Sky box RF2 outputs.

If RG6 is what's installed then there's not much you can do about it. Builders rarely give a stuff about cable quality. Just be thankful it's double shielded (It is, isn't it?). I've been to new builds where the cable isn't even that!

Sky probably won't use WF100 or the twin (shotgun) version of it unless the cable runs from the dish are very long. Anything up to about 10 m is probably going to be their version of WF63 which is the thin shotgun cable. It's more lossy than WF100, but since it's restricted to the satellite dish downleads to the boxes then it won't have a direct impact on your aerial distribution system. It's down to the Sky installer(s) to ensure you have enough signal at each Sky box. It wouldn't hurt to ask though if you can have shotgun WF100 installed.

The Sky installer will only provide the downleads from the dish to each box. You'll still need some WF100 of your own for the aerial hook-up and any incidental cabling. TIP: If you get white then you can make flyleads from the wall sockets to the TVs. That's always a good plan. Poor quality pre-made flyleads like you get free with gear are notorious for letting in interference and being very lossy.

Regarding F connectors, all the ones you'll be making up will be indoors. The simple screw-on F connectors will be fine. You don't need anything wayer-proof. RG6 is steel cable, but the steel core is anodised with a copper coating. It's not going to rust away.

4G filters: Unless you receive your local Freeview TV where one of the muxes is on ch59 or ch60 then it's doubtful you'll need one. They are available as an in-line filter if required.

Since channel 60~69 are now designated for 4G though there are aerials that chop off what used to be the top end of the Freeview frequency range. If the aerial doesn't receive those frequencies affected by 4G then your TV system can't be affected by them. If that's what you meant then yes, if you have the option then go for a ch 21~59/4G aerial as long as you're not paying silly money for it compared to a regular Log.

Haven't taken a close look but as I understand it the builder is leaving the coax cabling in the loft for me to do (i.e. terminate/connect) as I wish and this includes (but will check) four single feeds around the eaves and down a couple of drilled holes in boarding under the roof's guttering. These cables are hanging down ready for terminating/connecting to a Sky dish. No doubt it will be RG6 unless I am mistaken but would much rather the WF100 or twin version for primarily its weatherproofing properties. The roofspace will be awkward to route so will see if I can get the builder to replace this part of the cabling with a short run of WF100 as doing this inconjuction with Mr Sky TV man and having to then terminate and join with barrels will have me hard pressed.

Am I correct in thinking that with Loft boxes, the Freeview aerial feed is distributed unaltered and in HD for the relevant channels to all TVs? I understand the RF2 is a modulated feed but read about quality problems.

I looked at the SPC4 and its ability to combine RF2 but was thinking of distributing the aerial to both Sky+ boxes. Getting a little confused (easily done )

Oh, hang on then, you're saying that the builder is putting in RG6 for the Sky dish?

RG6 uses a steel core and aluminium foil, so it has a much higher DC resistance than an all copper cable (WF100/CT63/WF65). It doesn't do well at carrying current, so there's a voltage drop over distance that can cause problems for satellite systems. Your satellite boxes output a voltage to change the reception mode of the LNB. If the voltage drop in the cable is big enough then the LNB won't get sufficient voltage to switch properly.

I can see two issues arising. The first is the potential length of the combined cables. This is especially the case with Sky because they rarely install dishes now at much higher than stepladder height unless by prior arrangement; and then it's the Health & Safety equivalent of The Spanish Inquisition. So you might have to get someone in to run cable from the dish all the way up the wall to the loft to then join on to the cable inside the house for it then to come all the way down inside the house to where the boxes will be. 30m of RG6 is enough to create a a 1V drop at the LNB, and that's enough to screw up the switching.

The second issue is frequency losses. If the Sky guys use their thin twin shotgun cable then the losses in that are Titanic. They're even worse than RG6. That's why the stuff isn't (or shouldn't be) used on long runs. So you might have a combination of issues.

Thanks.

Checked today and stripped some insulation off to check screen and core. Took a magnet which didn't appear to stick to the core so assume it's Copper. It is marked RG6U AL Foam 14W28A. Took a couple of photos to show the cable.

http://postimg.org/image/k7axnslbx/
http://postimg.org/image/6drmvuz25/

Need to establish if there are two direct dish-to-room runs (2 per room) of this or whether the cables are cut in the attic and will do so tomorrow.

Sky installers here usually have no problems with installing dishes high (current one about 7 years old) is about 2 feet under the eaves in a 2 storey townhouse (Gnd and 1st) so hoping height isn't a problem else will get an independent to carry this out.

If the cable goes directly to both Sky+ locations, what is a typical setup to allow Freeview (incl HD) and Sky Modulated RF2 O/P to be viewed on all TVs (3 single feed from loft plus the two Sky+ units). Just to clarify, there are 3 remote TVs with just one aerial point, and the two Sky+ boxes both have their required dual LNB feed plus two single cables for RF2 return and Aerial. I want to get an unaltered terrestrial signal to all TVs but not sure if the RF2 feed reduces quality of this signal? Was considering SPC4 purely to combine the dual RF2 inputs from both Sky+ boxes to one for a single-inputted DA and thought the outputs (incl. Freeview) were unaltered or is this incorrect?

Thanks again.

If the magnet doesn't stick then it's not steel; well not unless it's stainless, but that would be unusual. The other possibility is copper coated aluminium. Try filing some of the outer to see what's underneath.

Before talking about the wiring, it's the normal practise to nominate Sky boxes for certain people or rooms. This avoids the control clashes.

A typical way of working is to have the lounge Sky box allocated as the master, so it's normally mum & dad's. If there's a TV in the master bedroom then the lounge Sky box is the one that is the 'first go-to' when watching from the master bedroom. All of mum & dad's programming/timer recordings are directed at that box. It occupies analogue TV channel '1'.

The second box is allocated to the kids. It lives on analogue TV channel '2'.

Ordinarily the TV directly above each box would be the normal viewing set for that Sky receiver. The local connection is made via HDMI or SCART depending on the type of box. The other box in the system can be seen by switching from AV to analogue RF, and then to channel 1 or 2 depending on which box needs to be viewed.

Other TVs around the house follow the same analogue RF channel selection. All TVs also have access to Freeview by switching to DTV.


Wiring up then....

Roof/loft aerial down to master Sky box. RF2 out goes back up to the loft and in to one input on the PSC4f. (This gets Freeview in to the system for all the house TVs.) The output from the SPC4f then goes to the aerial distribution amp. The outputs from the amp feed each TV.

The second Sky box doesn't need an aerial feed in to it. Just take the RF2 out up to the loft also. It goes in to the second input on the SPC4f. This combines the two RF feeds. The two sky boxes need to be on different RF out channels. This is done from the Sky box set-up menus. The SPC4f instructions will detail this, and if not then there's plenty of online guides including Sky's own website.

Could probably check tomorrow regarding the copper core and if it's a copper conductor I presume it's OK for outdoor connection to the LNB? Have read about using Silicone grease to weather proof connections but how and where is it applied?

I have read about the SPC4 and its one TV input but given RF2 sends this signal back out is there still unaltered Freeview and HD of the same? Was thinking a direct TV feed to a Distribution Amp without an RF2 return to avoid any signal loss. This pushes the price up for a more feature-packed D.A. but the cheaper loft boxes only have a VHF (no use to me) and a UHF input such as THIS.

If the signal from the local transmitter is as strong as you've suggested then any losses going through the sky box (FR in to RF2 out) won't be significant. Don't mess about with fancy aerial disti amps. Remember KISS; not the band but the acronym.... Keep It Simple, Stupid. Do exactly what I've suggested and it will work.

Silicon grease: apply liberally to the exposed metal surfaces of the cable and the inside of the F connector.

OK thanks.

F140 Distrib. Amp to supply the three remote TVs?

Excuse my ignorance but what is the difference between the IO Link and Tri-link devices? I see the three port Tri-link allows an RF1 feed to the local TV directly but does this mean the dual-port IO Link is limited?

Do you want the ability to view the second Sky box on the lounge TV to check what's being watched or to set up recordings etc?


Yes ............ then buy the Global I/O Link

No ............ then buy the Triax I/O Link (mfctr part code #370419)

(btw, the Tri-Link is a different product altogether, - mfctr part code #370407)


(No) In this scenario, all you want on the lounge TV is to see the Sky HD box (connected via HDMI) and to have Freeview on the TV. The Triax I/O Link gives you the RF connections to make that happen.

The aerial feed comes in to the I/O Link. The master Sky box picture gets added to it, then the two outputs are both used. RF1 goes to the aerial socket on the local TV. That gives you Freeview. RF2 goes up to the SPC4f.

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(Yes) In this scenario the TV is still connected via HDMI, but there's no RF Feed from the Sky box to the local TV. If you think about it, it's obvious: at this point the aerial cable is carrying just Freeview and Sky box #1's signal. It won't get the second Sky box RF signal until cable passes through the SPC4f.

The whole point of this particular scenario is that you want to see Sky box No. #2 as well as the main box, so the lounge TV needs an aerial feed from the loft box.

There are three long RF cables going between the lounge and the loft:
* Cable #1 is the aerial feed
* Cable #2 is the RF2 return (Freeview + Sky box #1)
* Cable #3 is the aerial signal plus both Sky boxes

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