ᐅ Installation of a Satellite Dish System

Okay, no one would install a 40cm (16 inch) dish on a new build, so this probably isn’t an option here. Still, these dishes do exist and of course they receive a signal, but it is about 6dB weaker compared to an 80cm (31 inch) dish. This is exactly why it makes sense to amplify the signal directly instead of letting it be attenuated over 20 meters (66 feet) of cable first.
However, as mentioned, this usually doesn’t apply to new builds, since reasonable quality materials of appropriate size are typically installed.
In our case, the 85cm (33 inch) dish with multiswitch works perfectly right under the roof, and from there eight satellite cables with up to around 20 meters (66 feet) of cable run flawlessly.
In two years, we only had one brief outage during a heavy snowstorm that made it hard to see your hand in front of your face.

The main point remains that the original poster should contact a professional company.
By the way, large electronics retailers sometimes have installers who can handle this, and having a proper invoice should hopefully keep you on the safe side with your insurance.

Peanuts74 schrieb:
Everything is correct so far, but if I have a relatively small dish and therefore install an amplifier, it makes the most sense to place it directly behind the dish, not down in the basement.

I had already quoted and commented on the deleted statement in my notes:

Anyone feeding multiswitches with dollhouse-size antennas that have barn-door-wide beamwidths has certainly failed their profession as a commercial antenna installer. The gentleman remains silent when it comes to an amplifier as compensation for insufficient dish size.

Now to the revised text.

Peanuts74 schrieb:
Okay, no one will install a 40cm (16 inch) dish on a new build, so this probably doesn’t apply here. Still, these dishes do exist and of course they receive a signal, but it’s about 6dB lower than an 80cm (31 inch) dish. And this is exactly where it makes sense to amplify the signal right away instead of first attenuating it with 20 meters (65 feet) of cable.

Nothing against placing a multiswitch on the roof if it is always accessible and not installed in unheated spaces, which results in shorter cable runs. Although this setup no longer fully complies with the current DIN 18015-1 standard, it is still commonly practiced.

If cable attenuation causes a low signal level at the subscriber end, then more amplification without question is required—or a high-gain LNB or a higher-quality multiswitch with lower tap loss. Naturally, low signal levels cannot be compensated by placing the multiswitch at the antenna.

A directly amplified signal remains strong even after 20 meters (65 feet) of cable. In the satellite intermediate frequency (IF) range, signal levels as low as 30 dBµV can still be boosted without the output signal being buried in its own noise. For ASTRA reception (at 52 dBW) with a DigiDish 45 (32.2 dBi gain) and a standard-gain LNB (55 dB), and accounting for 20 meters (65 feet) of cable loss (–6 dB), you end up with a completely uncritical 68 dBµV. This still leaves a comfortable attenuation margin of about 20 dB for the rest of the distribution network.

Peanuts74 schrieb:
In our case, the 85cm (33 inch) dish with a multiswitch directly under the roof works perfectly, with eight satellite cables running up to about 20 meters (65 feet).

This statement is of little help to a user who wants to convert their building’s communal antenna system to satellite reception when the apartment cables exit in the basement. Installing the multiswitch on the roof does not help at all in this case, and it would be counterproductive nonsense with AGC-controlled single-cable distribution systems.

Dipol schrieb:

Facade antennas with at least 16 mm² Cu (25 mm² aluminum or 50 mm² other materials) must also be grounded when installed less than 2 m (6.5 ft) below the gutter or roof edge, or at a minimum distance of 1.5 m (5 ft) from the wall. Grounding is required unless both the antenna and cables

• remain within the protective zone,
• serve only a single residential unit, and
• the leakage currents of connected devices are below 3.5 mA (rms),

in which case, since 2011, besides lightning-current-capable grounding of the wall mount, equipotential bonding (EPB) of the cable shields is optional.

It is considered self-evident in DIN EN 60728-11 (VDE 0855-1) that rainwater downspouts, gutters, etc., which can conduct lightning currents into the protective zone, should not be located too close, so this is not explicitly mentioned.

As of December 20, 2020, the threshold for leakage currents was raised to below 5.0 mA (rms).