Using MoCA & DirecTV DECA for Home and Building-to-Building Networking

MoCA (Multimedia over Coax Alliance) is a technology that allows Ethernet to be transmitted over standard coax cable. It is one of the most reliable ways to move internet around a home, especially when running new Ethernet cable is difficult or impossible.

This page explains how to use both MoCA adapters and the much cheaper DirecTV DECA adapters to build a coax-based network inside a home or even between buildings.

Why Use Coax for Networking?

Underground CAT5/CAT6 cable is expensive, breaks down over time, and is easily damaged by lightning induction. RG6 coax, on the other hand:

• Is inexpensive
• Is already installed in most homes
• Handles outdoor runs better
• Is less susceptible to lightning damage
• Supports high-frequency MoCA signals

For long runs, detached garages, shops, or older homes, coax is often the best option.

MoCA vs DECA

MoCA adapters typically operate between 800–1675 MHz. This requires:

• Newer RG6 coax
• MoCA-rated splitters
• Higher-cost adapters ($40–$60 each)

DirecTV DECA (DirecTV Ethernet Coax Adapter) uses the MoCA standard but at a much lower frequency range of 400–700 MHz. This allows DECA to work on:

• Older RG6
• RG59
• Existing satellite wiring

And DECA units cost only $5–$10 on the surplus market.

Why DECA Is the Best Low-Cost Option

DECA is essentially “MoCA Lite” — same concept, lower frequency, cheaper hardware. It was designed to coexist with DirecTV satellite signals, so it works extremely well on any coax system.

DECA is perfect for:

• Sending internet to bedrooms
• Running internet to a garage or shop
• Connecting outbuildings using buried coax
• Wired backhaul for mesh WiFi
• Any home with existing satellite wiring

Types of DECA Adapters

Below are the common DECA units you’ll find:

• DECA “BB” (Broadband) Adapter — Desktop version with external power supply. Best for routers.
• DECA “R” Receiver Adapter — Originally for DirecTV boxes, but works anywhere.
• USB-powered DECA — Avoid unless you know what you’re doing.

Important: Choose the Right DECA

You want the DECA units that have:

• One coax connector
• External power supply

Avoid the DECA units that require voltage from a DirecTV receiver unless you also use DirecTV splitters designed to pass power.

USB-powered DECA units:

Dont really recomend these. Never connect it to your computer ot tvs USB port and a surege in the coax could pass into the USB.

• They do NOT work on USB chargers
• Computers detect them as HID devices
• They may work on TVs or game consoles

If your DECA is near your router, use the desktop version with the factory power supply.

Operation

The non USB versions have 3 lights the CLINK one will flash orange until it gets a lock This to show good connection I suspect. The usb versions dont act the same way i dont knwo why. They are automatic they sync with each other and the one with internet becomes the master. So you can add a splitter and add lots of them wired out from the splitter. When ordering on Ebay look for the above one with a power supply.

Splitters for DECA

DirecTV SWM splitters (green label) are ideal because they are designed to pass DECA frequencies between output ports.

These splitters have:

• A built-in band stop filter on the input
• Low loss between output ports
• High compatibility with DECA frequencies

Using Normal Splitters

You can use normal splitters, but:

• Loss may be higher
• You may need a MoCA band stop filter on the input
• Splitters must NOT pass voltage unless required

Experimentation is sometimes needed to find the best configuration.

Performance

DECA typically delivers:

• 80–100 Mbps real-world throughput
• 2–5 ms latency
• Excellent stability

This is more than enough for:

• Streaming
• Security cameras
• General internet use
• Mesh WiFi backhaul

Lightning & Power Surge Protection

When I first started experimenting with DECA links between buildings, I blew up one of the original USB-powered units during a lightning event. The surge traveled through the coax, went straight into the DECA, and then continued out the USB port — destroying the USB jack on the computer.

If you are running DECA or MoCA between buildings, you must treat the coax like any other outdoor line. That means:

• Install a proper lightning protector on any CAT5/CAT6 that leaves the building
• Use a grounding block on the coax at both ends
• Bond the grounding block to the building’s electrical ground
• Never power DECA units from USB when used outdoors — always use the factory power supply

After adding grounding blocks and surge protection, I have not had a single failure. DECA is extremely reliable as long as the coax is properly grounded and the USB-powered units are avoided for outdoor runs.

2026 Notes

DECA adapters are widely available as surplus equipment, often brand new. They remain one of the cheapest and most reliable ways to build a coax-based network inside a home or between buildings.

More photos and wiring diagrams will be added soon.