Long, Narrow Apartments: Fixing the Far-End Bedroom

The router sits in the living room at the street end. The far bedroom is 50 feet away, with two open doorways in between and not one masonry wall on the path. On paper that works. In practice the back bedroom gets one bar and drops video calls, while the kitchen halfway down the apartment is perfect.

Long, narrow apartments fail in a way square ones do not, and it has very little to do with the 50 feet. It is the doorways — specifically the second one.

Everything is strung out on one axis#

A long, narrow apartment — a railroad flat, a shotgun unit, a floor-through in a walk-up — is typically 12 to 18 feet wide and 45 to 65 feet deep, an aspect ratio of roughly 3:1 or steeper. Take 800 square feet two ways. As a 28-by-28 square, the longest run inside is about 40 feet and every room touches a common middle. As 15 by 55, the longest run is nearly 57 feet and the rooms sit in series like carriages.

That gives you two problems at once. There is no central position: the middle of the plan is somebody's bed, and the coax lands at the street window, so the router is stuck at one end of the longest dimension in the building. And coverage is a chain, not a disc: the back bedroom is four or five obstacles deep, all in series.

The general apartment case — congestion, a single concrete core, the hallway fix — is covered in Wi-Fi extender placement in an apartment. What follows is the part specific to a long, thin plan.

Why the cliff comes after the second doorway#

An interior doorway is not a gap in the signal path. In a narrow apartment it is the signal path.

At 5 GHz the wavelength is about 2.4 inches, so a 32-inch door opening is more than a dozen wavelengths wide. Energy through it stays fairly well collimated: stand on the straight line running through the opening and you lose almost nothing. Step sideways behind the adjoining wall and you are living on diffraction around the frame and weak reflections off the far wall.

As rules of thumb at 5 GHz:

• Straight through an open interior doorway, on the axis: 0 to 3 dB.
• The same doorway, six to eight feet off the axis: 8 to 15 dB.
• A second doorway offset from the first, so no straight line survives: another 10 to 20 dB.
• Through the stud wall beside the doorway instead: 5 to 8 dB per wall.
• A closed solid-core door on the path: 4 to 6 dB; hollow-core, 2 to 4 dB.

The first doorway is nearly free when it lines up. The second is where you fall off, because two offset apertures in series leave no straight route at all — the signal goes through walls or around two corners, and pays both times.

As a running budget down a 55-foot apartment, starting from about -32 dBm beside the router:

Typical ranges for this geometry, not measurements we took. The pattern is the point: the fall is not smooth but flat, flat, then a 10 to 15 dB step at one specific place.

Find the jog#

Classic railroad flats often have their openings in a genuine line, and where that holds, 5 GHz travels down the apartment far better than the floor area suggests. What breaks it is almost always a renovation: a bathroom, closet block or stacked utility shaft dropped into the middle of the plan, pushing the route into a 3-foot passage down one side. That offset is your cliff, and a slow walk on a video call will find it within a step or two.

The mid-corridor rule#

Put the extender on the long axis, at the last outlet that still has an unbroken straight line back to the router, and confirm the router reads about -60 to -67 dBm there.

That window governs extender placement generally; the reasoning is in the signal window an extender needs behind it. What is different here is where it lands. The loss arrives as one step here, not a slow fade, so the answer is not really a fraction of the distance: it is the room immediately before the jog — typically 40 to 55 percent of the way down the corridor.

Do not push past the jog. On the far side, the extender's own link back to the router has to cross the aperture break you were trying to solve; it will show two or three bars, rebroadcast that marginal link at full power, and your phone will cling to it from halfway down the apartment. The extender is not there to be near the bedroom — it is there to re-illuminate the passage, so the last doorway becomes a first doorway again. Nor should you pull it back too far: beside the router, its forward bubble dies at the same jog the router's does.

Three adjustments worth a few dB each once the room is right: waist height or above rather than a baseboard outlet, out in the open rather than tucked behind a dresser, and external antennas vertical, which puts the strongest part of the pattern in the plane of the floor.

A worked plan for a 55-foot railroad flat#

780 square feet, 15 feet wide, 55 feet front to back: living room at the street window with the coax and router, then kitchen, then middle bedroom, then a bathroom-and-closet block that squeezes the route into a side passage, then the far bedroom.

1. Draw the long axis as one straight line from router to far bedroom and mark every opening it crosses — here, two doorways and the passage past the bathroom.
2. Mark the jog: the first point where that straight line stops working and you would have to step sideways to keep going. In this apartment, about 38 feet in.
3. Walk the axis with a video call running, pausing a few seconds every few steps. You are hunting the step change, not a gradual fade.
4. List the outlets in the room before the jog — the middle bedroom, and the kitchen end nearest it.
5. Pick the outlet furthest along the axis that still has a clear line back to the router and shows a strong link, not amber, on the extender's own indicator.
6. Plug in, wait two minutes for the link to settle, then test in the far bedroom with the door in its normal position.
7. If the far bedroom improved but is still marginal, move one outlet toward the router and retest. In a narrow apartment that is usually the fix: the failure mode is a weak backhaul, not insufficient reach.

What a good outcome looks like:

Again, typical ranges rather than a measured result. A far bedroom near -60 dBm behind a dual-band extender that keeps a separate link to the router will usually hold a video call and a 4K stream. A single-radio unit roughly halves whatever throughput reaches it, so budget for that.

When an extender will not fix a narrow apartment#

• Two jogs, or an L at the back. If the plan doglegs twice, no single position sees both the router and the far bedroom, and signal does not turn two corners cheaply — see L-shaped floor plans and the room around the corner.
• A masonry spine or a stacked wet wall across the axis. When the block in the middle is concrete or a tiled shaft full of pipework rather than stud partitions, there is no aperture to route around, and a repeater on the near side just publishes a strong signal that still cannot get past.
• Chaining a second extender to reach 65 feet. Every wireless hop costs throughput, so a chain is the most expensive way to buy distance — daisy-chaining two extenders covers the narrow case where two units on separate legs are fine.
• Full bars and slow anyway. If speeds crater in the evening while the signal reading barely moves, that is congestion, not coverage, and a repeater makes it worse.

Two alternatives worth trying first. Move the router along the axis — coax and fiber have more slack than people assume, and 12 feet toward the middle lifts the whole far half of the apartment for free, as the router placement basics explain. Or run one flat Ethernet cable under the baseboard trim to the middle bedroom, which turns a marginal repeater into a proper second access point; turning an old router into a wired access point covers how.

Doing this on a floor plan first#

The whole answer turns on a geometric question — where the straight line breaks — that is far easier to see drawn than to feel while walking around with a phone.

Draw the corridor in Range Up as it actually runs, including the bathroom-and-closet block that pushes the route to one side, and set the material preset to the building you live in — raising the wall loss value if the spine is masonry or tiled wet wall rather than studs. Put the router at the street window. The heatmap draws the cliff for you: a broad band of good color down the front half, then a hard edge at the jog you would otherwise have to hunt for on foot with a call running. Mark the far bedroom as the room that has to work, and the automatic search compares the outlets on the near side of that edge and shows what its favorite would do to the back of the apartment. A winner that buys the bedroom only three or four decibels is the geometry telling you to run a cable. Draw your own corridor, or start with the wider extender placement guide.