Why Comcast Wi-Fi Struggles in Larger Martha's Vineyard Homes (And How to Fix It) - Tech Tips

The most common call I get from Martha's Vineyard homeowners

The phone rings, it's a homeowner in Edgartown, and the conversation usually starts the same way: "I'm paying Comcast for gigabit and the Wi-Fi in my kitchen is terrible. Can you tell them to fix it?"

I've had some version of this conversation hundreds of times in homes from Aquinnah to Oak Bluffs. And almost every time, when I show up with a laptop and plug an Ethernet cable directly into the modem, the connection is fast. Sometimes it's a little under the advertised speed, but it's usually fine. The problem isn't the internet coming into the house. The problem is how the Wi-Fi is being distributed once it gets here.

That's an important distinction, because the fix isn't a phone call to Comcast. It's a home network solution sized to the building you actually live in.

Internet on Martha's Vineyard: what most homes are actually using

A quick reality check before we go further. For most homes and businesses on Martha's Vineyard, Comcast (Xfinity) remains the primary internet provider. Many down-Island homes rely on Comcast, while some up-Island properties use Starlink as either a primary internet connection or a backup option.

Either way, the conversation about Wi-Fi coverage is mostly independent of which one you're using. Whether Comcast or Starlink is delivering the internet, the same limitations of relying on a single router show up.

Comcast isn't usually the bottleneck

Here's the basic chain: Comcast (or another ISP) delivers internet to a modem inside your house. The modem hands the signal to a router, which broadcasts Wi-Fi. Most homes have a single combo unit that's both modem and router in one box — and that single box is expected to cover the entire property.

For a 1,200 square foot ranch in Vineyard Haven, that's often fine. For a 4,500 square foot 1890s farmhouse in West Tisbury with a finished basement, a guest cottage, and an outdoor dining area? Not a chance. The modem can pull all the speed Comcast sends. The Wi-Fi radio inside that combo unit just can't reach far enough or push through enough walls to deliver it.

Before you call your ISP, run two quick tests:

Plug a laptop directly into the modem with an Ethernet cable and run a speed test (fast.com or speedtest.net). If you're getting close to your plan speed, the line is fine.
Stand next to the router and run the same speed test on your phone. If that's also fast, but the speed in a distant bedroom is slow, you have a coverage problem, not an internet problem.

Upgrading from 800 Mbps to gigabit doesn't fix coverage. It just gives you faster internet at the spot you were already getting good Wi-Fi.

Why one router can't cover a larger Vineyard home

Wi-Fi is a radio signal. Like any radio signal, it gets weaker the further it travels, and weaker still when it has to pass through obstacles. Manufacturers love to advertise "covers up to 3,000 square feet" on the box, and that number is a marketing fantasy — measured in an empty warehouse with no walls and no other Wi-Fi networks nearby.

In real homes, the picture is different. From what I've seen across the Island, once a home gets to roughly 1,500 to 2,000 square feet, a single router starts to struggle — and that's before you factor in the things that make it worse:

Multiple floors. Wi-Fi travels horizontally much better than vertically. A router in the basement covers the basement and maybe the first floor. The upstairs bedrooms get weak signal.
Long hallways and end-to-end layouts. Some Chilmark homes are built long and narrow, parallel to the water. A central router has to push signal much further to reach either end.
Finished basements. Concrete floors between you and the router on the first floor will absorb a tremendous amount of signal.
Guest houses and detached cottages. A separate building, even one only 30 feet away, is functionally a different planet for Wi-Fi.
Outdoor entertaining areas. Decks, pool houses, and patios are where people actually want to be in the summer, and they're exactly where a single indoor router has the most trouble reaching.
Home offices in basements or above garages. These are the spots where work-from-home actually happens, and they're often the worst-covered rooms in the house.

I've seen 1,600-square-foot capes with finished basements where Wi-Fi is patchy, and 2,400-square-foot single-story homes where one well-placed router is fine. Square footage is a starting point. Layout and construction matter just as much.

Why old (and new) construction makes it worse

Vineyard homes are a Wi-Fi engineer's worst case in two different ways.

Older homes — the captain's house in Edgartown, the antique cape in West Tisbury — were built with materials that are great for shelter and terrible for radio waves. Thick plaster walls reinforced with metal lath act like a Faraday cage. Brick chimneys and stone fireplaces routinely block 80 to 90 percent of the signal trying to cross them. Plaster on lath is significantly worse than modern drywall for Wi-Fi.

Newer custom builds aren't necessarily better. Modern 2×6 framing with dense closed-cell spray foam insulation, radiant barriers, foil-faced rigid foam, and metal-clad ductwork all absorb or reflect Wi-Fi signals. I've seen brand-new homes in Aquinnah where the master bedroom is 25 feet from the router and the signal drops by half because of what's inside the walls.

A few materials worth knowing about, in roughly the order I see them cause problems:

Brick and stone fireplaces — the single largest signal blocker in most homes
Metal ductwork and HVAC equipment — basements and utility rooms
Plaster walls with metal lath — almost any pre-1960s Vineyard home
Radiant barriers and foil-faced insulation — newer high-performance construction
Tile bathrooms and masonry features — kitchens and bathrooms are usually the worst rooms
Refrigerators and large appliances — they're metal boxes full of water

None of this is anyone's fault. It just means that whatever Wi-Fi you have needs to account for what your house is actually made of.

Internet speed and Wi-Fi coverage are two different problems

I want to make this concrete because it's the source of so much confusion.

Internet speed is how fast data can travel between the internet and your house. Comcast sells this. It's measured in megabits per second. A speed test next to your modem will tell you exactly what you're getting.

Wi-Fi coverage is how reliably that speed reaches every corner of your home. No ISP sells this. It depends entirely on the equipment inside your walls and where it's placed.

You can have one without the other. Symptoms of a coverage problem (not a speed problem) include:

A speed test next to the router shows 800 Mbps, but the bedroom shows 15 Mbps
The Sonos speaker in the kitchen keeps disconnecting from the system
The smart TV in the den buffers in the middle of a movie
Zoom calls in the home office drop every 20 minutes
The Ring camera at the front door goes offline for hours at a time
Streaming on the porch barely works even though the house has gigabit

If any of those sound familiar, paying Comcast more money will not fix them. You need different equipment and better placement, not faster service.

Good news: many Vineyard homes already have the wiring for a fix

Here's where a lot of homeowners are pleasantly surprised. If your house was built or rewired anytime in the last 20-plus years, there's a real chance the builder ran Cat5 or Cat5e cable to phone jacks throughout the house. They did this for landline phones — but those same cables can almost always be repurposed for Ethernet.

That means in many cases, wireless network upgrades for larger Vineyard homes don't require ripping open walls. The wiring is already there. The phone jack in the upstairs hallway becomes the home for a ceiling-mounted access point. The cable in the den becomes a wired backhaul to the router in the basement.

Even in older homes without existing structured wiring, modern installation techniques — running cable through closets, along baseboards, or up through unfinished basements and attics — can get a clean wired install with minimal disruption. The walls in a 1920s Vineyard Haven cottage don't have to be torn apart to add proper coverage.

Why access points beat range extenders, every time

When homeowners try to solve a coverage problem on their own, the usual first move is a plug-in range extender from Best Buy. They usually make things worse.

A range extender takes the existing Wi-Fi signal, repeats it, and rebroadcasts it. That works on paper, but in practice it cuts your real-world throughput roughly in half (the extender has to talk to your router and to your devices on the same radio), creates a second Wi-Fi network with a different name, and your phone constantly fights about which one to connect to. Your kids' iPads get stuck on the weaker one. The Sonos drops.

A properly placed access point is a different animal entirely:

Each access point has its own wired connection back to the router (Ethernet backhaul), so it isn't fighting for radio time — the same setup that handles 4K streaming in an Oak Bluffs gingerbread cottage will handle a busy summer Saturday in a five-bedroom Edgartown home
All access points broadcast the same network name with seamless roaming, so your phone or laptop moves between them as you walk through the house without dropping the connection
They're built for sustained load — a dozen devices on a Zoom call, a 4K stream, multiple Sonos speakers, security cameras, smart home sensors — without falling over

For professional Wi-Fi systems covering 3,000+ square feet, two or three ceiling-mounted access points fed by Ethernet will outperform any consumer mesh kit by a wide margin, especially for Sonos, smart TVs, work-from-home setups, and security cameras that need consistent connectivity.

Where Starlink fits in on Martha's Vineyard

Starlink has changed the game on the Island, but probably not in the way most people expect.

As a primary connection: for homes in parts of Chilmark and Aquinnah where cable internet options are limited or where homeowners want additional redundancy, Starlink can be an excellent solution. The latest hardware delivers very usable speeds, low enough latency for video calls, and works in spots where cable internet simply won't reach.

As a backup: even for homes with strong Comcast service, Starlink is becoming a popular failover. When a storm takes down a cable line — and yes, that happens on the Vineyard — Starlink keeps the alarm system, the smart locks, the work-from-home setup, and the cameras online. For vacation rentals and seasonal homes, that backup means guests don't lose Wi-Fi when they're on the property and you're off-Island.

Integration matters. Starlink's own router is fine, but it's not designed to be the brain of a structured home network. The professional approach is to use Starlink as an internet source and feed it into the same routing and access point system that handles the rest of the home. That way, devices don't care whether they're on Comcast or Starlink — the network looks the same to them.

For up-Island homes especially, a Starlink and Wi-Fi system designed together usually outperforms either piece on its own.

Seasonal homes, vacation rentals, and "it worked fine when I left" Wi-Fi

A particular pattern I see almost every year, usually in May and June: the homeowner closed up the house in October, everything was working, and now they're back for the season and nothing connects properly.

What changed isn't usually the equipment. It's everything around it:

The modem firmware updated over the winter and reset
The router's password changed during a forced reboot
Comcast quietly upgraded the modem and the network name is different
Smart bulbs, garage door openers, and thermostats fell off the network months ago and need to be re-paired
New devices the kids brought back add load the system never had to handle before

For seasonal homeowners, the question isn't only "does it work?" — it's "does it work without my having to call someone every spring?"

The same is true, often more so, for vacation rentals. A rental Wi-Fi system has to do something a year-round home doesn't: it has to work for guests who don't know your network and shouldn't need to. That means a clean, well-named network with a simple password (or QR code on the welcome sheet), enough coverage to reach the deck and the pool house, and rock-solid uplink so that when the storm rolls through, the guest's Netflix doesn't drop. Backup internet — almost always Starlink, on the Vineyard — is increasingly part of that conversation.

Homes that sit vacant for months also benefit from remote monitoring on the network itself: someone the property manager (or the homeowner) can call who can actually see whether the internet is up, whether the cameras are reporting in, and whether the alarm system is talking to the cloud. None of that is possible if the network is a consumer combo unit with no visibility.

If you manage a property — or own a property that someone else manages — a one-time evaluation in the off-season can save a real number of frustrated phone calls when you're back. You can schedule a consultation any time.

Signs your home actually needs a Wi-Fi upgrade

If you're not sure whether your situation calls for new equipment, these are the patterns I see most often:

Dead zones in specific rooms. A back bedroom, the guest cottage, the third floor.
Slow streaming despite fast internet. The speed test next to the router is great, but Netflix buffers in the living room.
Sonos issues. Random speakers drop off, groups won't form, the kitchen plays but the dining room doesn't.
Security cameras going offline. Especially exterior cameras on the corners of the house furthest from the router.
Smart home unreliability. Lights don't respond, thermostats lose connection, garage door openers stop working from the phone. (When this is a recurring pattern, the underlying fix is usually a better smart home network foundation.)
Poor outdoor coverage. The pool deck, the patio, the porch — gathering spaces where people actually want to be.
Work-from-home calls dropping. Zoom, Teams, Google Meet freezing or dropping mid-meeting, even when the speed test looks fine.

One or two of these on a bad weather day isn't necessarily a problem. A consistent pattern is.

Every Vineyard home is different

Here's the most honest thing I can tell you after years of doing this work on the Island: no two homes are the same. The right network for a 2,000 square foot year-round residence in Vineyard Haven is not the same as the right network for a 6,000 square foot seasonal home in Edgartown with a guest house and a pool house. The wiring is different, the construction is different, and the use case is different.

A good network evaluation starts with walking the property — looking at where the existing wiring goes, where the dead spots are, where the family actually uses Wi-Fi most, what other devices are on the network, and what the construction is hiding. From there it's possible to design something that fits — not the biggest system, the right one.

If you're a homeowner, seasonal resident, or property manager dealing with Wi-Fi problems on Martha's Vineyard, I'm happy to come take a look. You can request a network evaluation or call directly to schedule a service visit. There's no obligation, and in many cases the recommendation is simpler than people expect.

Whether you're dealing with slow Wi-Fi, Sonos dropouts, Starlink integration, security camera connectivity issues, or a complete network upgrade, the underlying challenge is often the same: getting reliable internet coverage to every part of the property. The solution looks a little different in every home, but the goal is always the same — Wi-Fi that just works.

Serving Martha's Vineyard

We've designed and installed Wi-Fi systems for homes and businesses across the Island — from year-round residences and home offices in Vineyard Haven and Oak Bluffs, to historic homes and seasonal rentals in Edgartown, to up-Island properties in West Tisbury, Chilmark, and Aquinnah where Comcast service is patchy and Starlink usually fills the gap. The same basic principles apply everywhere, but the right answer is shaped by the building, the wiring, and how the property is actually used. If your home is on the Vineyard and the Wi-Fi has been a problem, that's the work we do every day.

FAQ

Why is my Comcast Wi-Fi slow even though my speed test is fast?

Because a speed test only measures the speed at the spot you're standing. If you're testing next to the router and getting fast results, the internet plan is fine — but the signal getting to the back bedroom, the kitchen, or the porch is a separate question. That's a Wi-Fi coverage problem, not a Comcast problem, and upgrading your Comcast plan won't fix it. The fix is usually one or more properly placed access points wired back to the router.

Can old phone wiring be converted to Ethernet?

In a lot of Vineyard homes, yes. If the builder ran Cat5 or Cat5e cable to phone jacks in the last 20+ years, those same cables can almost always be repurposed for Ethernet. It's one of the most common reasons a Wi-Fi upgrade in an existing home is far less invasive than people expect — no walls torn open, just a swap at each end of the cable.

Is Starlink a good option on Martha's Vineyard?

For homes up-Island in parts of Chilmark and Aquinnah where Comcast service is slow or unavailable, Starlink is genuinely the best primary internet on the market today. For down-Island homes with good Comcast service, Starlink is increasingly added as a backup connection — especially for seasonal homes, vacation rentals, and properties with alarm systems or smart locks that have to stay online. The right answer depends on the location and the use case.

How many Wi-Fi access points does my house need?

It depends on size, layout, and construction. A 2,500 square foot single-story home in Vineyard Haven might only need two. A 5,000 square foot two-story Edgartown home with a guest cottage and outdoor coverage might need four or five. The honest answer comes from walking the property — not from a square-footage formula on a box.

Why does Sonos keep disconnecting?

Sonos is a really good early-warning system for an overloaded Wi-Fi network. The speakers themselves are reliable, but they need a stable, well-covered network to stay grouped and in sync. When Sonos starts dropping out — kitchen plays, dining room doesn't; speakers fall off the system; groups won't form — the underlying cause is almost always Wi-Fi coverage or interference, not Sonos. Fix the network, and the Sonos problems usually disappear at the same time.

Related services

Network & Wi-Fi Installation — design, install, and tune home networks for Vineyard properties of any size
Starlink Installation — primary or backup satellite internet, integrated with your existing network
Sonos Support — whole-house audio that actually stays connected
Smart Home Services — lighting, climate, locks, and cameras that work because the network underneath them works
Technology Support — the rest of what we do across Martha's Vineyard

If your Wi-Fi has been a problem for a while, the next step is straightforward: contact Anything iTech and we'll come take a look.