|Metal between the router and assorted kit can reduce signal strength, even block itcompletely. Metal can be as in a metal building; a building with metal re-inforcement in the walls (re-inforced concrete etc.); even some construction blocks might cntain mineral deposits with a high enough metallic content to affect signals.|
Microwaves too have been found to be an issue for some; but they would only impact briefly - when the microwave unit is in use (and that of course would be for a few minutes only?).
Generally one locates and connects a router as close to the point of arrival of the ISP in the house; but that's not always practical and seldom achieved. You lose nothing by trying various other locations in your home/office, as long as you can make that actual connection easily - and it has of course to a physical connection (a suitable cable) to the DSL point of arrival.
If you're on a service that uses the phone line, then there are assorted considerations around that system; not the least how the DSL is actually distributed at your home. Is it available at any phone outlet or not?
If via your tv cable service, then again one needs to know how the DSLservice has been made available within the house, and is it only at point of entry of the service.
If, for whatever reasons you cannot relocate the (your only/main) router you can resort to assorted options which allow both ethernet connections around the house "and" better wifi coverage. These opions being either the homeplug system, and/or a second router wihich would be connected to your main router via a cat-5/ethernet cable.
Have a good read of the info which Johnw has proffered, and perhaps post back with details re' how your DSL service arrives; over the phone line, via your tv-cable service, or is it even fibre all the way to your home? Frequently many fibre services are not fibre all the way, but actually copper the last stretch from the street cabinet to your home.
message edited by trvlr