TV cable length

Great, happy for you!
Have a good evening!

Happy crafting! If you have any other questions or if there are any issues, don't hesitate to reach out...

A medium cable loses 20 dB/100 m, which is about 6 dB for 30 meters, meaning 6 dB = 50% loss!!!
???
I disagree, that would mean the input signal is set at 12 dB, which is extremely weak...

Hello, small clarification for enthusiasts
It is important to distinguish between power gain and voltage gain
Power gain = 10Xlog(P1/P2)
Voltage gain = 10xlog(U1/U2)
So for an attenuation of 3 dB, we have an attenuation of 1.41 in voltage and 2 in power
For 6 dB: 2 in voltage and 4 in power
For 10 dB: 3.16 in voltage and 10 in power
For 13 dB: 4.47 in voltage and 20 in power
For 20 dB: 10 in voltage and 100 in power
So -6 dB corresponds to a loss of a ratio of 2 in voltage and 4 in power
Hoping this helps you reach an agreement ;)
Best regards

@ blux
a medium cable loses 20 dB/100 m or about 6 dB for 30 meters, meaning 6 dB = 50% loss!!!
???
Correctly translated, this means that at the end of the cable there is 50% (or half!!) of the input signal (which cricri87 confirms anyway)

I don't see where the input signal would be at 12 dB.

Hello, precision: 6 dB: 50% in voltage but 25% in power, it all depends on whether you reason in terms of voltage or power afterwards?

Well under tension since the sensitivity of the tuners is given in µV.

@seb150
I provided 2 responses because the 2 essential clarifications that should normally accompany the question were missing:
- individual antenna? or collective?
- antenna for satellite TV? (DVB-S2 standard), or antenna for TNT (DVB-T standard)?

Since it is a collective TNT, a 2-way splitter (-4dB) at the outlet should be suitable if standardized distribution values are met, knowing that the 30 m cable will lose < 6 dB. If it doesn't work with -10 dB, have a qualified technician come in to correct the distribution level at the outlet. Technicians do not appreciate the addition of amplifier splitters, as it can create malfunctions on other outlets due to wave reflections.

It is adjustable in power, start at minimum, never boost the signal too much, it's counterproductive.

Hello, same opinion, check on site 2 galli: take 17 vatc or patc 100% copper foil + braid
Prefer 15 prtc: even more efficient
Don’t bend the cable, watch out for tight loops
If your cable needs to pass, for example, after 15/20 m near a socket or a junction, install in it a distribution amplifier with one input and two adjustable gain outputs; this will restore the TV signal level and therefore compensate for the losses incurred by your 15/20 m of cable (in no case will the amplifier allow you to increase the antenna signal coming into your apartment, at best it will allow it to be equivalent) then the remaining 10 m will connect the amplifier output to the antenna socket of your second TV
Test with all your cable to see if the signal remains usable on all channels before considering installing a distribution amplifier
To take the antenna signal out of your apartment socket, do not use a T but a low-loss splitter with one input and two outputs (one to each TV)
Take care of all your connections, see on site 2 galli the F connectors Elbac as well as their assembly method which differs slightly from that of standard F connectors
Standard F connectors: http://www.antenne-vision.com/comment-monter-une-fiche-F-ccjaaaaaa.asp

20 years in cable television networks leave their mark.............. I think I master the subject
Just to say that the standard is often "nonsense" in collective installations and that if we add 30 meters of cable behind the socket, there's a one in two chance of not having a sufficient signal for good digital reception
He just has to try, and if it works as is, so much the better, but at least he'll be warned

I've seen cable network installations before, honestly, it's normal to have malfunctions, just ask the tenants, the cable is so thin that it doesn't exist commercially, and it's really crap. Not to mention the installers who come with a hefty bill, and when we look closely, we quickly realize that for the most part they are scammers.

Thank you for the amateur qualifelec, I am an antenna technician! ;) Having seen quite a few installations, even recent ones, the signal level at the user socket is rarely up to standard, many 'pros' are turning into antenna technicians and even new installations need to be redone... another one today for a building with 40 sockets
Personally, this is my job, I've been doing only this and nothing else for quite some time
I did such an installation yesterday and such an installation even allows the distribution of canalsat and freesat programs (English bouquet), after modulation on all TVs in the same household, all working well with TNT reception, and without the distribution amplifier, the usable signal was limited on TV2 and TV3 on one multiplex, now everything works
The use of a distribution amplifier is effective but should only be used wisely, it must be noted that each installation is a unique case, here we can only give the paths to explore, enlightened advice... of course, the intervention of a (real) antenna technician is the best solution.

+1
I confirm your words cricri87

Hombourgeois, please remember to collect your prize for winning the 50% game (see my response above, 11:44 AM).