Description
>> BECAUSE SIZE DOES MATTER. <<
Every AP you log is only as good as the fix under it. You can sniff every beacon on both bands, 2.4 and 5 GHz, and still hand WiGLE garbage if your position is wrong. A weak fix smears your map. A slow cold start burns the first mile of the drive. A lost lock under trees or between buildings drops whole streets out of the log. Your radios are hearing everything. Your GNSS is the bottleneck.
The Rabbit-Labs GNSS Upgrade Case is a drop-in replacement enclosure for the JCMK C5 Wardriver with a high-performance active GNSS panel antenna built into the lid. Move your C5 host board over, plug in one IPEX connector, close it up. Same device, same firmware, a much bigger ear pointed at the sky.
The antenna: a stacked dual-layer ceramic patch. Two dielectric ceramic radiators stacked on a 1mm FR-4 ground plane: a 50 x 50 x 6 mm element over a 40 x 40 x 6 mm element, tuned for the three primary GNSS bands:
- L1 / E1 / B1: 1575.42 MHz, 4.0 dBic peak gain at zenith
- L2: 1227.6 MHz
- L5 / E5a / B2a: 1176.45 MHz
Right-hand circular polarization (RHCP) to match the satellite signal, a return loss better than -10 dB across every band, and more than 20 MHz of bandwidth on each. Compared to the small single-band patch most compact GPS modules ship with, that is a lot more ceramic and a lot more ground plane catching the same weak signal.
The LNA: 31 dB of gain, 2.5 dB noise figure. GNSS signals hit the ground well below the noise floor. The integrated low-noise amplifier lifts them 31 dB (±2 dB) right at the antenna, before 150 mm of coax can add its own loss, with a typical 2.5 dB noise figure so it adds as little noise as possible doing it. A tinplate shield cover keeps the LNA isolated from the ESP32-C5’s own RF, and 55 dB of out-of-band rejection at ±100 MHz pushes back on the cellular and WiFi energy that floods a wardriving rig.
Built for the field. Rated for -40 to +80°C operation, RoHS compliant, fed by a factory-terminated RF-1.13 micro coax with an IPEX connector, and pre-installed in the lid so the patch faces the sky the moment you set the rig down.
Key Specs:
- Compatibility: JCMK C5 Wardriver (direct replacement enclosure)
- Antenna Type: Active GNSS, dual-layer stacked ceramic patch
- Elements: 50 x 50 x 6 mm + 40 x 40 x 6 mm dielectric ceramic
- Bands: L1 1575.42 MHz, L2 1227.6 MHz, L5 1176.45 MHz
- Peak Gain @ Zenith: 4.0 dBic (L1)
- Polarization: RHCP
- Impedance: 50 Ω
- Return Loss: better than -10 dB per band; bandwidth over 20 MHz @ -10 dB
- LNA Gain: 31 dB ±2 dB @ 20°C
- LNA Noise Figure: 2.5 dB typical
- Output VSWR: below 2.0
- Out-of-Band Rejection: 55 dB typical @ f0 ±100 MHz
- LNA Supply: 3.3V typical (10V max) via coax bias, 13.5 mA ±2 mA
- Ground Plane: 1 mm FR-4
- Shield: 0.2 mm tinplate
- Cable / Connector: RF-1.13 micro coax, approx. 150 mm, IPEX
- Operating Temperature (antenna): -40 to +80°C
- Enclosure: PLA
- Included: Enclosure with antenna pre-installed
- Not Included: C5 Wardriver host board, Wardriver Front Bezel (bring from your existing kit!), ESP32-C5-DevKitC-1, 18650 battery
Applications that matter:
Cleaner WiGLE Data. Better signal into the GNSS receiver means faster fixes, steadier tracking, and tighter positions on every logged network. Your map stops smearing.
Urban Canyons & Tree Cover. Downtown blocks, tree-lined streets, and parking structures are where small antennas lose lock. More gain and an LNA at the element hold the fix longer where it matters most.
Vehicle Rigs. Set the rig on the dash and the patch looks straight up. No external antenna cable through the door, no SMA hanging off the case.
Future-Ready Bands. The L2 and L5 elements are there for multi-band GNSS receivers. On today’s single-band L1 receivers, you still get the full benefit of the bigger L1 element and the LNA.
Same wardriver. Better sky. Better data.
▌README.TXT – INSTRUCTIONS FOR USE
Compatibility: A drop-in replacement enclosure for the JCMK C5 Wardriver. Your existing C5 host board, ESP32-C5-DevKitC-1, and 18650 battery move into this case. The active antenna requires antenna bias power from the GNSS receiver through the coax, which the C5 Wardriver’s GPS connection provides.
Step 1: Power Down Turn the C5 Wardriver off and remove the 18650 battery before opening anything.
Step 2: Open the Stock Enclosure Remove the enclosure screws and lift the cover. Note how the host board, DevKit, and stock GPS antenna are seated.
Step 3: Disconnect the Stock GPS Antenna Unplug the stock antenna’s IPEX connector from the GPS module. Lift it straight up at the connector body using a u.FL/IPEX removal tool or a thin plastic spudger. Never pull on the cable.
Step 4: Transfer the Host Board Move the C5 host board and with the DevKit installed and Front-Panel into the base of the new enclosure and secure it in the same positions.
Step 5: Connect the New Antenna Line the antenna’s IPEX connector up squarely over the GPS module’s socket and press straight down with a flat tool until it snaps in. Don’t press at an angle. IPEX connectors are small and rated for limited mating cycles, so seat it once and leave it.
Step 6: Route the Coax Lay the RF-1.13 cable in a gentle loop with no sharp bends, clear of screw posts and the lid seam, so it won’t be pinched when the case closes.
Step 7: Close & Power Up Close the lid with the antenna facing up, install the battery, and power on. Take the first fix outside with a clear view of the sky. A cold start can take a few minutes while the receiver downloads satellite data. After that, fixes come fast.
PRO TIP: A patch antenna sees best straight up. In a vehicle, keep the lid facing the sky and clear of metal. Some windshields have a metallic coating that blocks GNSS, usually everywhere except a small dotted zone near the mirror. If your fix is weak on the dash, try that zone.
▌DEBUG LOG – TROUBLESHOOTING
ISSUE: No GPS fix after installation. FIX: Reopen the case and confirm the IPEX connector is fully seated, pressed straight down. Then test outdoors with a clear sky view. The first cold start can take several minutes.
ISSUE: Fix is slower or weaker than expected. FIX: Check orientation: the lid must face the sky. Metal surfaces, metallized windshields, and dense buildings all cut signal. Also check that the coax isn’t pinched or kinked.
ISSUE: Position jumps or drifts near tall buildings. FIX: That’s multipath: signals bouncing off structures. Better gain helps hold lock, but no antenna fully cancels reflections. Positions settle once the view of the sky opens up.
ISSUE: Lid won’t close flush. FIX: The coax is likely caught on a screw post or the lid seam. Reroute it in a loose loop and close again. Never force the lid down on the cable.
ISSUE: Runtime is slightly shorter than with the stock antenna. FIX: Expected. The LNA draws about 13.5 mA from the GNSS receiver’s antenna supply to amplify the signal. That’s the cost of a stronger fix.
ISSUE: Stock antenna connector won’t come off. FIX: IPEX connectors grip tightly. Use a removal tool or slide a thin plastic spudger under the connector body and lift straight up. Never pry against the module or pull the cable.
▌SYS.WARN – WARNINGS, HAZARDS & DISCLAIMERS
Receive-Only Antenna. This is a receive-only active GNSS antenna. Do not connect it to any transmitter or RF power source. RF power on the antenna port will permanently damage the LNA.
Connector Care. IPEX connectors are fragile and rated for a limited number of mating cycles. Always disconnect by lifting straight up at the connector body. Never pull on the cable.
ESD Sensitivity. The LNA and the C5 host board are sensitive to electrostatic discharge. Work on an ESD-safe surface and touch a grounded object before handling.
Heat. Do not leave the rig in direct sun on a vehicle dashboard for extended periods. The antenna itself is rated to 80°C. but the plastic case printed in PLA can melt or deform.
Battery Safety. Always remove the 18650 battery before opening the enclosure. Follow all lithium battery safety guidance from your battery’s manufacturer.
Device Warranty. Moving your C5 Wardriver into a third-party enclosure may affect any warranty from its original manufacturer.
Legal Compliance. The reception and logging of radio signals is subject to federal, state, and local laws. While passive reception of most radio signals is legal in the United States, the interception of certain communications may be prohibited under the Electronic Communications Privacy Act (18 U.S.C. Section 2511) and other applicable statutes. Wardriving and wireless survey activity may be subject to additional regulations depending on jurisdiction. The end user is solely responsible for compliance with all applicable laws.
Intended Use. This product is designed for radio enthusiasts, wireless researchers, and wardrivers engaged in lawful signal reception, mapping, and research. Rabbit-Labs LLC does not condone or support use of this product for any unauthorized or illegal purpose.
Not a Toy. Contains small parts. Keep out of reach of children.
Disclaimer. This product is sold “as-is” for use by qualified individuals. GNSS performance depends on the receiver, the environment, and sky visibility, and is not guaranteed. Rabbit-Labs LLC makes no warranty, express or implied, regarding fitness for a particular purpose. Maximum liability shall not exceed the purchase price of the product.
© Rabbit-Labs LLC. All rights reserved. The Rabbit-Labs name and logo are trademarks of Rabbit-Labs LLC. JCMK, C5 Wardriver, and other product names are trademarks of their respective owners. Rabbit-Labs is not affiliated with or endorsed by JustCallMeKoko LLC.
