ALFA ARS-25-57A — Dual-Band Paddle Antenna (5/7 dBi)
一句話定位（One-liner）: The ARS-25-57A is a compact, semi-directional paddle antenna for 2.4 and 5 GHz — 5 dBi on 2.4 GHz, 7 dBi on 5 GHz. It is the travel-friendly middle ground between a stock dipole and a full panel: more gain than the stick antenna, less bulk than the wall panel.
規格總覽 (Spec overview)
| Item | Spec |
|---|---|
| Type | Directional paddle antenna |
| Bands | 2.4 GHz + 5 GHz |
| Gain | 2.4 GHz: 5 dBi ｜ 5 GHz: 7 dBi |
| Connector | RP-SMA (male) |
| Polarization | Linear |
| Design | Flat paddle, hinged, lightweight |
| Use case | Portable rigs, travel, labs that need a bit more range |
Overview
A "paddle" sits between an omni dipole and a flat panel: it is a small flat blade with mild directionality and real gain — 5 dBi on 2.4 GHz and a useful 7 dBi on 5 GHz. That band-dependent gain is sensible: 5 GHz needs the help more than 2.4 GHz, and 7 dBi on the 5 GHz band is where the ARS-25-57A earns its keep.
Where it shines:
- Portable/pentest kits — hinges flat, survives a backpack, screws onto any RP-SMA ALFA adapter.
- Laptop lab stations — more range than the stock dipole at the same weight.
- Semi-directional aiming — point it at the target AP for a bit of focus without the panel's full aiming discipline.
Where it does not: for a fixed building-to-building link, the APA-M25 (10 dBi panel) beats it; for full travel minimalism, use the stock antennas.
Concept: why a paddle, why 5/7 dBi
The paddle is the compromise node in that chain: it gives a real gain number (which the stock dipole's "5 dBi" omni figure arguably under-delivers in practice) while staying forgiving to aim. The 5/7 dBi split means the band that struggles most — 5 GHz — gets the larger share.
Install & connect
Step 1: Attach
Screw the ARS-25-57A's RP-SMA connector onto any ALFA adapter's RP-SMA antenna port. Finger-tight + a light eighth-to-quarter turn is enough.
Step 2: Deploy
Flip the paddle open so its flat face points toward the AP/station you are linking. Tilt and rotate while watching the adapter's signal reading.
Step 3: Verify
iw dev wlan0 link
Expected output: a signal: in dBm. Swing the paddle a few degrees at a time; keep the orientation that yields the least-negative number. Repeat on the 5 GHz band if your link uses it.
Advanced usage
- Monitor-mode aiming: start
tcpdump -i wlan0monand re-orient the paddle until the highest beacon count arrives from your target direction. - Two-antenna adapters: on the AWUS036ACM/ACH you can run one paddle + keep one on 5 GHz — but for multi-band links, both antennas should target the same band for coherent MIMO.
- Portable field kit: hinge the paddle flat for transit; the RP-SMA is replaceable if you ever snap the connector in the field.
Compatibility
| With | Result |
|---|---|
| Any ALFA adapter with RP-SMA antenna ports | ✅ Screws straight on |
| 2.4 and 5 GHz links | ✅ Both bands, 5/7 dBi respectively |
| Travel / backpack rigs | ✅ Ideal size and weight |
| Fixed long links (>200 m) | ⚠️ Consider the APA-M25 panel |
Troubleshooting
| Symptom | Diagnosis | Fix |
|---|---|---|
| No gain over stock antenna | Paddle pointing away / not fully seated | Re-aim at the AP; reseat the connector |
| Works on 2.4 GHz, weak on 5 GHz | 5 GHz needs more aiming precision | Tilt precisely; 7 dBi 5 GHz lobe is narrow |
| Connector wobbles | Loose RP-SMA | Retighten gently; do not overtighten |
| Folds back on it own | Hinge friction worn | Minor — orientation with the adapter's own weight is normal |
Related resources
- APA-M25 — the full-size panel for fixed links
- APA-M04 — 2.4 GHz-only panel
- ARS-NT5B7 — industrial WiFi 7 tri-band dipole
- Adapter comparison
- Troubleshooting index