Starting to think I really ought to tidy up the coils of cable in the wiring cupboard. Had a brief look around at multiswiches but don't really know which are good or bad makes or even a decent place to buy from.
The multiswitch needs to do DSAT (and if it outputs the relevant voltages/tones for a quad LNB that is already installed and working all the better), Be very convenient if it also distributed, Band II, DAB (might get a signal with a loft aerial) and whats left of Band IV and V for DTTV. There are 24 coax's in the cupboard but 7 of those are DSAT and terrestial aerials. So a 16 output unit will be just over full, but it's unlikely that all distribution drops will ever be used at the same time, so 12 outputs will probably do.
Even though this isn't a "shared dwelling" I assume the hefty earth bonding of the distribution cables is still a good idea. The plug-in modules seem like a very neat solution and less time consuming than the stand alone strips (and two less joints). Comments?
Would have tweakable input levels be an advantage bearing in mind any test gear is just the signal level/quality indication of consumer equipment. I do have a basic "adjust dish for maximum" satellite meter.
The output drops probably vary from about 10 m to 25 m (ish) so I don't think I really need to worry too much about variation of signal level across drops.
I can't really advise you with any authority because I've been retired years now and although Paul deals with such things we never seem to discuss it.
OK hang on a minute...
He says he's happy to use Vision and Triax.
Hang on, one of his kids is screaming because he can't get Netflicks to work.
Ahh...
You'll need to check on that yourself. It isn't a thing we would do. Makes replacement of the switch a slight problem because usually they go wrong at funny hours and you have to use what's in the van, and to only stock that type would be limiting.
Be very convenient if it also distributed, Band II,
Oh yes you want that. They all do it. Some choice of input config but I always used to use one-input ones and add my choice of diplexers/filters/attenuators.
There are 24 coax's in the cupboard but 7 of those
Oh get one that covers everything. It isn't worth giving yourself the hassle of mucking about changing cables over (if they're labelled the labels will all be wrong). And when switches go wrong, quite often it's individual outputs that die so it's good to have spares.
I agree.
Either way really.
Not really. You won't overload the switch with satellite signal. Lots of head room. Just blast it with everything the LNB can give it.
For UHF and VHF use external attenuators (or pre-amps).
No, because normally everything is at a much higher level than the receivers need.
However I have to say that doing this job without proper test equipment is a bit hazardous. You're OK unless something oddball happens, then it becomes a bit annoying.
which are >> good or bad makes or even a decent place to buy from.
Experience still counts, at least as far as what works physically and which approaches give the better result.
Thanks Paul.
working
Flexabilty of a Quattro LNB is understandable for a commercial operation and multi occupancy dwelling. If the multiswitch goes pop it has to be replaced to get all occupants back with service and a Quattro LNB allows the use of either "type" of multiswitch. Not quite the same for a self maintained single dwelling, if the multiswitch goes pop with a Quattro LNB it's no (or restricted) telly untill a new multiswitch is purchased, delivered and installed. A Quad LNB can have up to four outlets with full DSAT by just connecting those drops to the Quad LNB feeds, same for single FM, DAB and DTTV receivers. Much reduces the domestic strife if down time is less than an hour, rather than days...
That's handy. B-)
Single input, own diplexers etc makes sense, unless a multi input one has individual level tweaks I can see big signals in one band possibly overloading the amp(s). Not that big signals is going to be a problem here, at least not in band. The Air Traffic Control stuff from 121 to 128 MHz is very strong from Great Dunn Fell, far stronger than any broadcast signal.
outputs
I must admit I'm inclined to agree, I think the price difference 12 >
16 > 24 will be a big influence, Do unused outputs need to be terminated?
I'll be labeling them, the labels will be right. B-)
Now that's a useful bit of inside info.
earth
Ok, neatness OCD is screaming have all the incoming cables terminated along one edge of the mounting board, with enough slack such that any cable can reach any port. The functional/easier side is saying just lay neatly to each amp output and in the (unlikely) event of a drop needing to moved if it doesn't reach a short jumper can bodge it (ARGH!). B-)
Do you happen to know how these things work internally? Is it just a single output amp, followed by say 30 dB attenuators to each output port (giving 60 dB between ports), or individual amps per port? As you say a single port can die that would indicate the latter as there ain't much to go wrong with an attenuator.
I might be able to borrow a proper sattelite meter should there be something weird a miss. I'm well used to fault finding temporary installations right back to "unplug it all and start again from power"
Thanks for the response (and Johns), given me a starting point and that my thoughts are more or less on track. I'll have a look at what CPC has to offer from Vision and/or Triax.
The one I took apart on a rainy day had stripline tap-off units on a PCB. One long track with a lot of short tacks very close to it. The little ones were grounded via a 75ohm resistor at one end and the other end went to the output port.
or individual amps per port? As
It's the switching between band and polarisations that goes wrong, usually sticking on one permutation or sometimes two. Also you get bad connections (hairlines) on the output sockets when they connect to the PCB.
When an amp goes down you lose one permutation on every port.
The commonest fault on multiswitches is the PSU. Luckily that's fixable. They really don't like emp from lightning.
It'll be right... They are sort of identfied ATM up to five bands of sticky tape one some, then flags and numbers. Pencil numbers on the plaster above the sockets, OK until decoration takes place. B-)
Usefull stuff again Bill.
Had a quick look at CPC last night, the Vision EV5-516 seems good value for money. Comes with plug-in earthing bonding, switchable input level adjustment, was probably going to go for line powered and use a 12 > 18 DC-DC convertor as "the plan" is to have a decent sized
12 V supply and convert that for the various voltages the various boxes will want. Requires a Quattro LNB AFAICT.
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