FAQ
TL;DR: For star-wired RTV/SAT outlets on 15–25 m runs, assume ~6 dB loss per 20 m and “aim … about 60 dB.” Choose the smallest socket attenuation that still lands within 48–74 dB at the outlet. [Elektroda, TELMOR_PL, post #16667395]
Why it matters: Picking 1.5 dB vs 10 dB affects picture quality and avoids receiver overload in multiswitch systems; this FAQ helps homeowners and installers size attenuation confidently.
Quick Facts
- Target outlet level: approx. 60 dB within a safe 48–74 dB window for terrestrial bands. [Elektroda, TELMOR_PL, post #16667395]
- Approx. coax loss: ~6 dB over 20 m with good cable; factor this before choosing socket attenuation. [Elektroda, TELMOR_PL, post #16667395]
- End (terminal) sockets are for star installations; through sockets are for serial (loop-through) runs. [Elektroda, ad_min, post #16662610]
- Attenuated outlet elements act on VHF/UHF (TV/FM), not on the SAT path. [Elektroda, irekr, post #18404759]
- In multiswitch systems, attenuated sockets are rarely needed if levels are locally controlled. [Elektroda, irekr, post #18404759]
Which attenuation should I choose: 1.5 dB or 10 dB for an RTV/SAT end socket?
Use the least attenuation that keeps the outlet within 48–74 dB. With 15–25 m of quality coax (≈6 dB/20 m), 1.5–2 dB usually fits better than 10 dB. Overshooting risks under‑level signals; undershooting can overdrive the tuner. Aim near 60 dB at the outlet. [Elektroda, TELMOR_PL, post #16667395]
How do I size attenuation if I only know cable length?
Estimate cable loss, then pick the smallest socket attenuation that centers the outlet near 60 dB. Example: 20 m run ≈6 dB loss; if the multiswitch output is strong, 1.5–2 dB may still land you near 60 dB, avoiding overload. “We try to aim … about 60 dB.” [Elektroda, TELMOR_PL, post #16667395]
What level should I target at the socket for DVB‑T/T2?
Target roughly mid‑range, about 60 dB, staying within 48–74 dB at the outlet. This avoids both noise‑floor issues and tuner overload. If you measure above the window, add attenuation; if below, reduce it. [Elektroda, TELMOR_PL, post #16667395]
What’s the difference between an end socket and a through socket?
End (terminal) sockets finish a star branch and do not pass signal onward. Through sockets sit mid‑run in serial (loop‑through) wiring and include pass‑through plus defined tap loss. Pick end sockets for star, through sockets for serial. [Elektroda, ad_min, post #16662610]
Does a 10 dB RTV/SAT socket also attenuate the SAT output?
No. The specified attenuation applies to the VHF/UHF TV/FM path. The SAT leg remains effectively unattenuated by that element. This design prevents starving LNB-fed SAT signals while trimming terrestrial levels. [Elektroda, irekr, post #18404759]
Are attenuated sockets necessary in multiswitch installs?
Often no. Multiswitch systems usually control local VHF/UHF levels, so added outlet attenuation brings limited benefit. As one expert notes, “the use of attenuated sockets does not make much sense if multiswitch is used.” [Elektroda, irekr, post #18404759]
I’m using a Terra MR508 and 20–25 m runs—what should I buy?
Start with 1.5–2 dB end sockets in main rooms. Verify outlet levels; adjust only if measurements exceed the 48–74 dB window. This approach keeps you near the 60 dB target without unnecessary loss. [Elektroda, TELMOR_PL, post #16667395]
Can I mix 1.5 dB in the living room and 2 dB elsewhere?
Yes. Use lower attenuation where longer or higher‑priority runs need margin. Community guidance confirmed 1.5 dB and 2 dB as acceptable standard RTV/SAT end sockets for star wiring. [Elektroda, Anonymous, post #18404336]
What happens if the level is too high at the outlet?
You can distort the tuner front end (“the head in the receiver”). Symptoms include pixelation or dropouts despite strong readings. Add attenuation to bring the outlet back within the 48–74 dB window. [Elektroda, TELMOR_PL, post #16667395]
How do I choose between 1.5 dB and 10 dB when unsure of device specs?
Default to less damping. It preserves margin, especially on 15–25 m runs. If later measurements show excess level, step up attenuation. Excessive fixed loss is harder to recover without amplifiers. [Elektroda, andpol 33, post #16662587]
Do attenuated outlets exist for specific markets or use cases?
Yes. They’re common where cable TV networks blend with building SAT distribution, notably in parts of Germany and France. Typical multiswitch‑only homes don’t need them when levels are managed. [Elektroda, irekr, post #18404759]
Is there a quick method to size socket attenuation without a meter?
Use a three-step estimate: 1) Compute cable loss (~6 dB/20 m). 2) Check multiswitch output spec or installer notes. 3) Pick the smallest outlet attenuation that keeps the estimated outlet near 60 dB. Validate later with measurements. [Elektroda, TELMOR_PL, post #16667395]
Will using the wrong socket type hurt performance?
Yes. Using a through socket in a star run adds unnecessary loss and mismatch; using an end socket mid‑chain breaks serial distribution. Match end sockets to star, through sockets to serial. [Elektroda, ad_min, post #16662610]
What’s a practical failure case to watch for after installation?
If channels pixelate after adding a high‑loss outlet (e.g., 10 dB) on a long run, the outlet level likely fell below 48 dB. Swap to a 1.5–2 dB model to restore headroom. [Elektroda, TELMOR_PL, post #16667395]
Are there any buying notes from the thread?
Contributors confirmed the shown 1.5 dB and 2 dB Legrand end sockets as suitable picks for star‑wired RTV/SAT. Choose based on measured or estimated levels per room. [Elektroda, Anonymous, post #18403576]
