I am new to the community and I would also like to thank you for the hard work.
I am planning to install a first node in my summer house in Northern France. It is based on the Mikrotik LR8 and 868 Omni antenna. I have a view on 15 km from my house on one direction, which is on a hill (but not on top of the hill). I am planning to replace an old satellite dish. My questions
Does it matter if the omnidirectionnal antenna is close to the house wall (50 cm)?
Should the omni antenna be on top of the house or is 2 meters sufficient?
In LoRaWAN a “node” typically refers to an “end device” which is a battery powered sensor or (in rare limited cases) actuator.
In contrast the LR8 is a “gateway” - a more expensive and more power hungry device (almost always mains powered) which bridges LoRaWAN air signals from end devices to the Internet where they can reach a relevant LoRaWAN server, such as TTN’s infrastructure.
So it seems like you are talking about deploying a gateway, not a “node”
The antenna should be as high and as free as possible.
To answer your questions:
This will reduce the coverage significantly compared to an antenna on top of the roof
The antenna should be on top of the roof e.g. on a mast
The antenna is omnidirectional. What you see is the vertical diagram, the horizontal diagram is a circle
Depending on where you are, take care of the output-power. The antenna has a gain of abt. 3 dBd, this gain can be used to compensate the loss of the antenna-cable or you have to reduce the tx-power by 3dB.