it depends of the walls, floors, trees, etc between you and the base, but any DECT Phone can go straight line up to 100 yds.

It work perfectly outside

Yes work outside but no to far from the base

Mine works about 100 feet out from the house.

The best answer I can give to this is that I live on about 1/3 of an acre and don't have any problem using the handsets anywhere on the lot.

Yes, it will work outside.

At about 75' no problem. Have not tried farther distances

Yes, both bases can charge the headsets and just the large one has to be connected to the phone line.

both have to be plugged into an outlet

The satellite phones still need to be near an outlet if you want to charge up the phones. I am assuming that vertical distance does not affect the signal. We have 3/4 of an acre and get coverage almost all the way to the end of the yard. Should cover the second floor of a house.

Yes..both handsets need an electrical outlet BUT each can be on a different floor. I have the main base in the basement and the extra base in the livingroom above.

yes both bases have to be plugged into an electrical outlet but the can be used on separate floors

Yes, you have to have both base plug into the electrically outlet and they can be on separate floors.

The base is pretty sturdy and the phone stands upright
when you sit it down.

The bases a very light weight a little flimsy but no worse than other brands

base is sturdy , did not flip over

The main base of this unit is fairly sturdy. We have a seven and four year old and it does not get tipped over very often. The satellite phone bases are rather light and tip over easily. We have them in remote areas of the house so they don't see a lot of traffic. I believe all three bases can be wall mounted, which might ease your fears.

They are lightweight, but do not seem flimsy. I have them leaning against the desk back. When I moved the base with the phone to the middle of the desk and removed the telephone, the base did not tip. Don't know if this is helpful to you. Not certain what would happen under other circumstances.