A weak Wi-Fi signal in remote rooms is a common problem, especially if the router is installed in an awkward location. Many users try to solve this by moving the antenna, but are limited by the supplied cable's length. Extending the Wi-Fi antenna's coaxial cable seems like a simple solution, but in practice, it requires taking into account wave impedance, signal attenuation, and the quality of the connectors. An incorrect approach can not only reduce internet speed but also damage the router's transmitter.
In this article we will look at 5 Reliable Methods for Extending Cable — from using ready-made extension cords to soldered connections — and we'll also tell you how to calculate the maximum length without critical losses. You'll learn what connectors (SMA, RP-SMA, N-type) compatible with your antenna, how to avoid standing wave effect, which destroys equipment, and what tools are needed for the job. We'll also cover typical errors that cause the signal to disappear completely.
Why can't you just twist the two cables together?
The most common mistake is trying to connect cables using twisting or tape. Coaxial cable for Wi-Fi (usually RG-58, RG-174 or LMR-400) has a strict wave resistance (50 Ohms for most antennas). Any damage to the shield or central core leads to:
- 📉 Loss of signal up to 3–10 dB for each poor connection (this reduces the network range by 2–3 times).
- ⚡ Reflected power (VSWR), which overheats the router's transmitter transistors.
- 🔌 Short circuit between the braid and the central core under moisture or mechanical stress.
Even if the signal remains after twisting, over time, oxidation of the contacts and corrosion of the screen will lead to a complete loss of communication. By comparison, a properly soldered connection to the connectors loses no more than 0.2–0.5 dB, which has almost no effect on the quality of the connection.
⚠️ Warning: Cheap "Chinese" extension cords from AliExpress often have a 75 ohm impedance (like TV cables), which is incompatible with Wi-Fi equipment. Using them is guaranteed to reduce network speed by 30-50%.
How to determine your antenna connector and cable type
Before purchasing an extension cord or materials for self-installation, it is necessary to identify:
- Connector type on the antenna and router (most often SMA or RP-SMA, less often N-type or TNC).
- Cable diameter (For example, RG-58 — 5 mm, LMR-400 — 10 mm).
- Wave resistance (indicated on the cable marking, usually
50 Ohm).
Connectors SMA And RP-SMA They are similar in appearance, but have reverse polarity: SMA the central pin is on the "dad", RP-SMA — on the "mother" side. An incorrect selection will result in an inability to connect. To avoid mistakes, use the table:
| Connector type | Appearance | Where is it used? | Max. frequency |
|---|---|---|---|
| SMA | Central pin on the "dad" | 2.4 GHz antennas, TP-Link, Asus routers | up to 18 GHz |
| RP-SMA | Central pin on the "female" | 5 GHz antennas, Ubiquiti equipment | up to 6 GHz |
| N-type | Large threaded connector | Powerful antennas, access points | up to 11 GHz |
| TNC | Looks like N-type, but with a thread of a different pitch | Industrial equipment | up to 11 GHz |
If the markings on the cable have worn off, measure its diameter with a caliper:
- 📏
4.8–5.0 mm— RG-58 or RG-174 (thin, flexible). - 📏
6.1–6.5 mm— RG-213 (hard, low loss). - 📏
9.5–10.3 mm— LMR-400 or H-155 (for long lines).
Method 1: Ready-made extension cords with connectors
The simplest and most reliable method is to purchase a ready-made extension cord with the required connectors. The best options are:
- 🛒 Extension SMA male → SMA female (length 1–5 m) – for most routers.
- 🛒 RP-SMA extension - if the antenna has reverse polarity.
- 🛒 Cable LMR-400 with connectors N-type - for powerful antennas (for example, Ubiquiti Rocket).
When choosing, pay attention to:
- Attenuation (given in dB/m). For example, RG-58 loses
0.6 dB/mat 2.4 GHz, and LMR-400 - only0.22 dB/m. - Shielding qualityCheap cables have thin braiding that provides poor protection against interference.
- Sealing of connectorsFor outdoor installation, choose models with rubber seals.
Example calculation: if you extend the cable by 5 m using RG-58, the losses will amount to 5 × 0.6 = 3 dBThis will reduce the signal strength by half! For comparison, LMR-400 at the same length it will only lose 1.1 dB.
⚠️ Caution: Do not purchase extension cables longer than 10 m without first calculating the attenuation. At 5 GHz, the loss in RG-58 reach 1 dB/m — already at 5 m the signal will weaken by 3 times.
Compatibility of connectors with antenna and router|
Cable attenuation at your frequency (2.4 or 5 GHz)|
Availability of shielding (foil + braid)|
Sealing of connectors for outdoor installations|
Reviews of a specific model (frequent complaints about breaks)-->
Method 2: Soldering the cables
If you can't find a ready-made extension cord or need a non-standard length, you can connect the cables by soldering. This method requires care, but results in minimal losses (0.1–0.3 dB for connection). You will need:
- 🔧 Soldering iron (power 40–60 W) with a thin tip.
- 🧵 Solder POS-61 or Sn60Pb40 (with flux inside).
- 🧴 Flux for soldering copper (for example, LTI-120).
- 🛠️ Heat shrink tubing with a diameter of 8–12 mm.
- 📏 Wire cutters and stripper for removing insulation.
Step-by-step instructions:
- Remove the outer insulation from both cables.
15–20 mm, without damaging the screen. - Unbraid the wire and twist it into a bundle. Tin the bundle and the central conductor.
- Connect the central wires with a soldering iron, then solder the braids together.
- Place the heat shrink tubing over the connection and heat it with a hair dryer.
Critical points:
- 🔥 Do not overheat the cable - the insulation may melt, exposing the central core.
- 🧲 The braid must be connected around the entire circumference, otherwise the screen will lose its effectiveness.
- 🚫 Avoid "cold soldering" (dull, porous solder) - such a connection will quickly oxidize.
What happens if the screen is soldered incorrectly?
If the braid is not connected all the way around or has breaks, the cable begins to radiate interference like an antenna. This leads to:
1) Deterioration of reception due to interference.
2) The appearance of "dead zones" around the cable.
3) Possible conflicts with other Wi-Fi networks in an apartment building.
Method 3: Connecting using adapters
If soldering seems difficult, you can use adapter connectors (barrel). For example:
- 🔌 SMA female → SMA female — for connecting two cables with male connectors.
- 🔌 RP-SMA → SMA adapter - if you need to change the polarity.
Advantages of the method:
- ✅ Does not require a soldering iron.
- ✅ Allows you to quickly disconnect the cable if necessary.
- ✅ Suitable for temporary extension (e.g. testing antenna position).
Flaws:
- ❌ Signal loss is higher than with soldering (
0.3–0.7 dBfor connection). - ❌ Not suitable for outdoor installation (moisture and dust penetrate the connector).
- ❌ Cheap adapters often have poor contact of the central conductor.
For outdoor use, choose adapters with rubber plugs or treat the connection silicone grease to protect against corrosion.
Method 4: Using an active amplifier
If you need to extend the cable by 15+ meters, passive methods (extension cords, soldering) will lead to critical losses. In this case, active signal amplifier (For example, TP-Link TL-ANT2408CL or Ubiquiti AMO-2G13). The device is installed in the middle of the cable and compensates for attenuation.
How does this work:
- The amplifier is connected to a power source (usually
5–12 Vthrough PoE injector). - The signal from the router is fed to the amplifier input, cleared of interference and amplified
10–20 dB. - The amplified signal is transmitted further along the cable to the antenna.
Important nuances:
- 📶 The amplifier must support your frequency (
2.4 GHzor5 GHz). - 🔌 Power consumption - up to
500 mA, so the power supply must be powerful enough. - 🚫 You can’t install the amplifier close to the router - this will lead to receiver overload and deterioration of communication.
⚠️ Warning: Powerful amplifiers (more than 20 dB) may violate legal norms EMS (electromagnetic compatibility) in your country. Exceeding the permitted transmitter power is punishable by a fine from regulators (in Russia, up to 50,000 rubles under Article 13.3 of the Code of Administrative Offenses).
Method 5: Replace the cable with a low-loss one
If your router supports removable antennas, the most effective way to extend the range is to replace the standard cable with a low-loss (For example, LMR-400, H-155 or Times Microwave LMR-600). These cables have:
- 📉 Fading
0.1–0.3 dB/m(2-5 times less than RG-58). - 🛡️ Double shield (foil + braid) to protect against interference.
- 🌧️ Moisture and UV resistant (for outdoor use).
Example: replacement RG-58 10 m long LMR-400 the same length will reduce losses 6 dB to 2.2 dB — this is equivalent to increasing the signal power by 4 times!
How to choose a cable:
| Model | Attenuation at 2.4 GHz (dB/m) | Max. length without amplifier | Price per meter (2026) |
|---|---|---|---|
| RG-58 | 0.6 | up to 5 m | 30–50 ₽ |
| RG-213 | 0.4 | up to 8 m | 80–120 ₽ |
| LMR-400 | 0.22 | up to 20 m | 200–300 ₽ |
| LMR-600 | 0.15 | up to 30 m | 400–600 ₽ |
For outdoor installations, use cable with markings. PE (polyethylene shell) or UV-resistantAvoid cheap analogs—they often have a reduced center conductor cross-section, which increases attenuation.
Common mistakes and how to avoid them
Even experienced users make mistakes when extending cables. Here are the most common ones:
- 🔄 Using a 75 ohm TV cable (For example, RG-6). This will result in signal reflection and router overheating.
- 📦 Laying cables near sources of interference (electrical wiring, microwaves). Will increase the noise level.
- 🌡️ Lack of moisture protection For outdoor connections. Will lead to corrosion and connection failure.
- 🔌 Connecting the amplifier in reverse direction (to the router input). This will damage the transmitter.
How to check the connection quality:
- Use the app WiFi Analyzer (Android) or NetSpot (Windows/macOS) to measure signal level before and after extension.
- If the speed has dropped by more than 30%, check all connections short circuit with a multimeter.
- For accurate diagnosis use SWR meter (SWR meter) - the value should be less than
1.5.
⚠️ Attention: If after extending the range the router starts to overheat or reboot spontaneously, immediately disconnect the antenna! This is a sign high KSWR (standing wave ratio), which destroys the transmitter output stage.
FAQ: Frequently asked questions about extending the Wi-Fi antenna cable
Is it possible to extend the cable by 50 meters without loss?
No, any extension introduces attenuation. At this length, you'll need:
- Cable with minimal attenuation (eg LMR-600 —
0.15 dB/m). - Active amplifier in the middle of the line (for example, on the 25th meter).
- Power supply of the amplifier PoE or a separate cable.
Even in this case, the losses will amount to 7.5 dB (excluding the amplifier), which will reduce the signal power by 5–6 times.
What is the difference between SMA and RP-SMA connectors?
SMA And RP-SMA (Reverse Polarity) are identical in appearance, but have reverse polarity:
- SMA male — the central pin on the male connector.
- RP-SMA male — the central pin on the female connector.
If you mix them up, the antenna simply won't connect. To determine the type, look at the router connector:
- If the pin is inside, it is female (Mother).
- If the pin is outside, it is male (dad).
How to protect cable connections outdoors?
For outdoor installation:
- Use sealed connectors (For example, N-type with rubber gaskets).
- Process the connections silicone grease or lithium grease.
- Close the connection heat shrink tubing with an adhesive layer.
- Fix the cable to the wall with plastic clamps, avoiding sagging (water accumulates in them).
Avoid running cables over metal surfaces as this will increase interference.
Why did the Wi-Fi speed drop by half after extending the cable?
Possible reasons:
- A high attenuation cable is used (eg RG-58 at 10 m it gives losses
6 dB). - Poor contact in the connectors (oxidation, unsoldered).
- The cable is laid near sources of interference (for example, along a 220 V power cable).
- Mismatch of wave impedance (for example, TV cable is 75 ohms instead of 50 ohms).
Solution: Check all connections with a multimeter (the resistance between the braid and the core should be infinite). Replace the cable with a low-loss one or install an amplifier.
Can I use a USB extender for my Wi-Fi antenna?
No. USB extenders are designed to transmit data via the USB protocol, not high-frequency signals. Connecting a Wi-Fi antenna via USB will result in:
- Complete loss of signal (USB cable is not shielded for 2.4/5 GHz frequencies).
- Damage to the router port due to voltage mismatch.
Exception - specialized USB Wi-Fi adapters (For example, TP-Link TL-WN722N), which are connected to a PC, not a router. In this case, extending the USB cable is possible, but the maximum length should not exceed 3 m (due to limitations of USB 2.0 protocol).