COAX (SAT) cable splitter, permanent under the floor (junction box?)? - Page 1
Forum section: electronics / general

author: onesixright
author_rank: Frequent Contributor
timestamp: November 20, 2021, 11:25:32 am
content: Hi All,I hope everybody is doing alright!I have a few rooms where on both sides I want to have a sat wall box (f-connector). Now these f connectors (from Schneider Unica) don't have a "pass thru" option.What I need is to split the cable in the room but this will be under the floor. My concern is, once the floor is in, I will never able to reach this (without breaking).Any ideas what would be the best way to install ajunction boxunder the floor, via a some coax splitter or is there any other acceptable way of doing this?Thanks!Roger

author: themadhippy
author_rank: Super Contributor
timestamp: November 20, 2021, 12:49:58 pm
content: why not just link from one wall box to the next?yea you might use a bit more cable but at least your joints are accessible

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 20, 2021, 01:26:15 pm
content: I would put the splitters in the walls behind the connector plates, keep in mind each splitter reduces the signal by a bit more than 3dB. An alternative would be coax connectors that have built in switches to pass the signal on if there's no cable connected, but those might be hard to find.

author: onesixright
author_rank: Frequent Contributor
timestamp: November 20, 2021, 01:41:51 pm
content: Quote from: themadhippy on November 20, 2021, 12:49:58 pmThanks, the problem is the Schneider SAT unit, don't have an option for IN/OUT (so you cannotchain multiple SAT wall outlets). See picture.

author: onesixright
author_rank: Frequent Contributor
timestamp: November 20, 2021, 01:43:03 pm
content: Quote from: NiHaoMike on November 20, 2021, 01:26:15 pmThanks. Is this 3db loss specific to using a splitter?

author: richard.cs
author_rank: Super Contributor
timestamp: November 20, 2021, 03:23:57 pm
content: The (at least) 3 dB loss is inevitable because half the energy goes one way and half the other, so with an ideal lossless splitter each output gets half of the input power which is very nearly 3 dB less (because 10^-0.3 ~= ½). Some splitter designs are resistive, these loose 6 dB but are simple/cheap to construct and offer better wide band performance.In most satellite TV systems you can "waste" quite a bit of signal in splitters and lossy cables before it starts to degrade overall system signal to noise ratio.

author: fourfathom
author_rank: Super Contributor
timestamp: November 20, 2021, 03:36:33 pm
content: I don't know about your gear, but the satellite TV and internet boxes I've seen send "phantom" power through the coax to run the active circuitry at the dish. A regular splitter isn't going to work with this.Or are you trying to split a coaxial output between the sat-box and the TV?

author: themadhippy
author_rank: Super Contributor
timestamp: November 20, 2021, 04:32:01 pm
content: how is the cable connected to the wall plate,if its an f socket on the back use a T piece likeIf its screw terminals then a normal T piece with a short bit of cable to the wall box

author: flolic
author_rank: Frequent Contributor
timestamp: November 20, 2021, 05:01:24 pm
content: Quote from: fourfathom on November 20, 2021, 03:36:33 pmExactly. To connect multiple STB-s to one dish you need LNB with multiple outputs, or you need device called multiswitch.LNB frequency range and polarisation is controlled by two voltage levels and injected 22kHz signal, because of that you can't just use passive splitter but need active device.

author: Monkeh
author_rank: Super Contributor
timestamp: November 20, 2021, 05:05:34 pm
content: Quote from: onesixright on November 20, 2021, 01:41:51 pmErr, on one you write 'in', on the other 'out', and you use a cable to connect them.

author: Gregg
author_rank: Super Contributor
timestamp: November 20, 2021, 07:17:35 pm
content: I would run two individual coax cables back to your cable box and label them. While the floor is uncovered, it won't cost much more to buy the additional cable. You can then split or switch them near the source.If it was my project, I would also run a Cat6 cable to each wall and leave them coiled up behind the wall; but I like to use hard wired systems.

author: tkamiya
author_rank: Super Contributor
timestamp: December 11, 2021, 05:50:28 pm
content: Placing something that could possibly fail or need updating in inaccessible place is a bad idea. You said it's going to be under the floor. Is this a must? Can this be installed in a box flush to the floor? Can a splitter be placed near antenna and just run two cables to each terminating location?You get one lightening hit nearby and splitter will likely break. Corrosion is another possibility. Accessibility is a must.