Kitz Forum
Chat => Tech Chat => Topic started by: tickmike on March 16, 2015, 09:12:26 PM
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TV/FM Whole House Distribution Amplifiers. :hmm:
I have a Out side TV & FM aerial and Mast Head Amp which feeds in to a mix of old TV amplifiers in the house which in-turn feed various rooms.
I want to replace the 'mix of old TV amplifiers' and have new 'Distribution amplifier' in a central location.
The largest I can find is an 2 x 8 way one (2 x VHF Radio + 2 x TV ).
http://www.labgear.co.uk/category/amplifiers/distribution-amplifiers/16-output-mains-powered-digilink-amp/1002/1014/255/
Does anyone know of any larger ones or could I use a splitter from the aerial feeds and feed two of the above ?, or any advice on a way to get 16 room TV/FM supply.
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Do you also use satellite?
I use a multiswitch - see first post here for a picture (https://www.avforums.com/threads/ronski-finally-starts-his-cinema-room.1882755/).
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Do you also use satellite?
I use a multiswitch - see first post here for a picture (https://www.avforums.com/threads/ronski-finally-starts-his-cinema-room.1882755/).
No Satellite :no:
Thanks for the link but I have your project up on another tab ;) and it looks like it's coming on great. :)
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Hallo Tickmike
I have a SLXGOLD booster in my loft. Mine gives 4 outputs all covering Fm up to uhf. You could certainly use a splitter on the input to give you 16 outputs The only drawback is if your initial signal strength is low you might impair the signal to noise ratio. Luckily with our digital systems these days that's not usually a problem. You might notice it on analoue FM but if you use DAB that should not be affected. The SLX8G is available from TLC Direct for £19.20 in my 2013 catalogue but they have a web site. Good luck.
Tony
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I'd probably choose the simple route and fit a second aerial (or aerials). ;)
A level up from us; we have an 8-way amplifier with 2 inputs (TV and FM) which suffices, especially as we now also have a quad-LNB satellite dish.
Though my amplifier (can't recall the brand/model) does also have a single high-level output connector for (presumably) feeding a daisy-chained secondary unit. Check the specs for such a facility.
Edit, slight correction:
My 8-way Antiference A280D developed a fault a while back and I replaced it with a Philex SLX6 which is just 6-way (plus "full") output. Must have been after the dish arrived.
The instructions do specifically say that the "Full" (18dB gain) outlet can then be further split.
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Useful info thanks ;).
old set up.
I have two coax cables from my present amp outputs to each room, UHF TV and VHF FM.
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The new set up.
The combined output from these 'Labgear' amps are sent down one coax cable to each room, I would have to use some kind of faceplate that can then split the signal into a TV coax socket and a VHF FM coax socket .
What type of faceplate do you use .?
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No idea what brand as I got them ages ago, but just has a single coax input behind and two coax outlets on the face, labelled TV and FM.
Simple small circuit board inside that presumably has a basic filter setup to split the signals appropriately. Works fine.
They look exactly like this one:
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww.beststuff.co.uk%2Fstore%2Fimages%2FT%2Fh84028.jpg&hash=53a3cd383efcabbf91f009f21427cbd162bc1c5d)
I don't bother with these for TV-only locations, just normal ones.
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I use that same faceplate in the lounge but not bothered elsewhere.
Tony
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Thanks.
My problem is I have already made some face plates some years ago with the two sockets on each with it's own coax running back to the old amps.
But also on these 'Double socket size' faceplate's is a 'Audio' socket, they are in each room .
Any idea what I would need to make up my own 'splitter' circuit ?.
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Since there are both UHF and FM frequencies available, if you only have a device that needs one or the other, just use one socket. If you need both, a resistive splitter between the two will do. It might be a bit pricey to use retailed splitters, you could make your own if you have a soldering iron. A Y type splitter needs 3 x 25 ohm resistors or a delta type 3 x 75 ohm.
Tony
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Since there are both UHF and FM frequencies available, if you only have a device that needs one or the other, just use one socket. If you need both, a resistive splitter between the two will do. It might be a bit pricey to use retailed splitters, you could make your own if you have a soldering iron. A Y type splitter needs 3 x 25 ohm resistors or a delta type 3 x 75 ohm.
Tony
Thanks tony I will try that :), I probably have all the bits to do all my face plates ;).
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Connected the TV side of the distribution amp up today and I'm Not impressed with the TV picture, BBC 1, 2 are ok but we tried to use Freeview ch 37 and it kept cutting off :'(
I tried other rooms and they where the same :(.
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I would suspect that the initial signal level is low and the additional attenuation caused by the splitter on the distribution amp is taking the sig/nouse ratio below what is acceptible for the receivers being fed. a better/resited aerial or mast head preamp might be the next things to try. If you have a local friendly aerial man/dealer he may be able to measure the signal level coming off your aerial.
Tony
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Due to our location (limited LOS to Waltham Tx, same for Sutton Coldfield Tx) I fought a losing battle from 2000-2011 with TV amplifiers & DVB-T.
The problem with DVB-T is that its simply not as resilient as the old analogue system - mainly because the Tx power levels are usually < 20% of the analogue Tx levels. It doesn't help that many of the multiplexes have what I consider to be borderline overloading in terms of the number of channels & channel encoding.
On top of the problems with amplifying noise & dreadful signal discrimination I found that various receiver front-ends would be overloaded while others were fine - this from the same amp output. So I bit the bullet & got an amp with variable gain on each output & put that in the loft. That was OK until one of the frequent changes to multiplexes happened (we've had 5 changes of frequency & probably a dozen changes to multiplex encoding) which would require manual adjustment of outputs again.
I even installed a couple of these (older models) : http://www.silicondust.com/products/hdhomerun/hdhomerun-connect-au/ as it was getting to the stage that streaming over the network was easier than balancing out each receiver.
Then "HD" came along using 256QAM which would require new DVB-T receivers.....
Anyway I got sick of this & decided to get Sky to install a sat dish with 4 LNBs (outputs). Hooked a "Freesat" (DVB-S) box up to the spares & it works much much better than "Freeview" (DVB-T).
tl;dr if you have garbage reception then DVB-T is a waste of time & money - get a dish installed & switch to DVB-S.
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Rizla makes a very valid point about overloading and is a further prompt to get the signal levels measured. You can sort out overloading (if that is the problem) by inserting attenuators in the feeds to the receivers and seeing if there is an improvement. If there is none it's probably the input signal level. It all points to finding someone who can measure signal levels.
Tony
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Yeah I have dozens of SMA attenuators in a box but it worked out cheaper to get a variable power amp than buy SMA<->push-fit co-ax adaptors.
It still required adjustment every time they shuffled frequencies/multiplexes around so what works this week might not next week. That's the problem with having lower power reception - you start with rubbish & amplifying rubbish is problematical.
If you don't have lots of DVB-T stuff (unfortunately most of us do) I think I'd just advise people to use DVB-S. You can get a dish with 8 LNBs & that's enough for four rooms without any sort of distribution equipment as long as each cable is < 20m. We've never had any issues with rain/snow causing picture problems but our cables are a lot shorter than 20m.
DVB-T in the UK is only going to get worse as the available frequency band gets squeezed by mobile/data services. Combine this with more 256QAM (HDTV) channels & unless you have great reception its going to cause progressively more problems.
I'm not sure I'd bother with "FM" - its entirely possible "FM" will be toast inside a very few years. The fastest variants of g.fast will require that frequency band to be freed up* in order to prevent interference - various UK govts have been trying to get rid of it for years anyway.
Anyway I'm no real help to the discussion as I failed at this years ago :)
*people will still utilise that band but permitted power levels will drop to tiny fractions of that used now.
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Looking at this map we are about 1 mile from the edge of the green area, so lack of signal in the first place, I have a feeling that a very tall pine tree and a old tram bridge is in the LOS. :'(
If it's fine at the weekend I will have a look at the aerial and it's mast head amp, I have it on the gable end wall on a 2" aluminum scaffold pole and I can lower it down ;)
http://www.ukfree.tv/transmitters/tv/Waltham