important notice - this is a prototype/testing system, it is not meant to be used in the real world at the moment and is currently in violation of several FCC laws, it is hard but I am currently working out a way to use fmcw as my SDR supports full duplex, please do not try this at home with the hardware, but if you would like to try the software I do plan on releasing a version that's not zipped up but I'm trying to fix the software first, and because it stated all the way at the very bottom of this read me, AI was used in this but not to completely create it, it was used for polishing and because I suck at writing paragraphs, the code the hard work and the numbers were all crunched by me and a piece of paper, it's taken well over 2 months to get this far, and I'm still learning along the way. and feel free to give me any suggestions, comments or criticism.

Small Portable Weather Radar

A self-contained mobile weather radar system built from a $5 salvaged RV satellite dome, a cheap SDR, and open source software. No internet required. No subscription. No NWS data dependency. Your own radar returns, updated every 10-30 seconds, mounted on your vehicle.

Built in Kokomo, Indiana. Motivated by real severe weather — including tornadoes that came within a few miles of home.

Why This Exists

Every storm chaser on the road is looking at NEXRAD data that is 4-6 minutes old, from a radar station that may be 100+ miles away. At close range the NWS beam overshoots low-altitude storm features entirely due to Earth curvature and beam elevation. When a supercell is 10 km away and moving at 40 mph, 6-minute-old data from a distant station is not situational awareness — it is history.

This project generates local radar returns from a vehicle-mounted dish. Updates every 10-30 seconds. Range 3-40 km depending on configuration. Detects rain cores, hail shafts, and tornado debris balls. Costs under $200 to build.

Professional mobile Doppler radar trucks (DOW — Doppler on Wheels) do the same thing. They cost $500,000+. This costs less than a tank of gas.

What It Looks Like Running

Live PPI radar display served as a web page, accessible on any device on your local network or remotely via Cloudflare tunnel. Offline Indiana county and road map overlay. Four-tier auditory alert system. GPS position tracking. Session recording with standalone HTML replay. Transit mode that locks the dish forward while driving and resumes full sweeps when stopped.

How It Works

Theory of Operation

The Winegard Carryout Anser GM-5000 is an automatic RV satellite dome — a motorized prime focus parabolic dish in a weatherproof radome. It was designed to find and track TV satellites. We repurpose it as a scanning X-band radar antenna.

The Eagle Aspen LNB inside operates at 11250 MHz local oscillator frequency. Injecting a signal at 850 MHz into the LNB's IF port causes it to upconvert and radiate at 10.4 GHz through the dish — the same X-band frequency used by weather radar. Rain, hail, and debris reflect a portion of that energy back. The LNB downconverts the echo back to 850 MHz for the SDR to capture.

TX injection frequency math:
  LNB LO (11250 MHz) - Target (10400 MHz) = 850 MHz
  Inject 850 MHz → dish radiates 10.4 GHz

The azimuth motor sweeps the dish continuously, building a Plan Position Indicator (PPI) image from signal strength at each bearing.

Signal Chain

SDR TX port (850 MHz)
    → F-to-SMA adapter
        → MAIN F port on dome
            → LNB upconverts to 10.4 GHz
                → dish radiates into sky
                    → rain/hail/debris returns echo
                → dish captures echo
            → LNB downconverts to 850 MHz
        → SEC F port (dedicated receive path)
    → SDR RX port

The MAIN port handles TX injection. The SEC port (second LNB output, active simultaneously) provides a clean dedicated receive path. A bias tee on the SEC coax powers the LNB. No shared TX/RX path, no switching, no backfeed concern.

Hardware

The Dome

Winegard Carryout Anser GM-5000

Spec	Value
Dish type	Prime focus parabolic, polished aluminum
Dish diameter	~18-22 inches
Gain at 10 GHz	~32-33 dBi
Beamwidth	~4-5°
Azimuth	Belt driven motor, ~360° in 10 seconds
Elevation	Manual set and lock
Wind rating	35 mph maximum
Weight	~16 lbs
Includes	25 ft power cable, 20 ft RG6 coax

LNB: Eagle Aspen 501353

Spec	Value
Input band	12.2–12.7 GHz
LO frequency	11250 MHz
IF output	950–1450 MHz
Outputs	MAIN + SEC (simultaneous)
LNB bias power	External — supplied via coax

Motor Control Port

The dome has a thin plastic knockout panel on the base housing. Pop it out with a flathead screwdriver — it is factory-designed to be removed (thin score lines in the plastic, identical to the insert between a milk jug handle and body). The RJ-25 RS-485 control jack is immediately behind it.

RJ-25 pinout (pin side up, cable end toward you):
  Pin 1: GND
  Pin 2: T/R-
  Pin 3: T/R+
  Pin 4: RXD-
  Pin 5: RXD+
  Pin 6: Not connected

Baud rate: 57600, 8N1

Supported SDR Hardware

The software supports multiple SDR backends selectable via config.py:

SDR	Type	Config value	Notes
Zynq7020 + AD9363	2TX 2RX full duplex	`"pluto"`	Recommended — separate TX1/RX1 ports, libiio compatible, boots Pluto firmware from SD card
ADALM PlutoSDR	Full duplex	`"pluto"`	Official Pluto, same libiio backend
HackRF One	Half duplex	`"hackrf"`	Single ANT port handles TX and RX, switches ~1-2µs
RTL-SDR V4	Receive only	`"rtlsdr"`	No TX capability — passive monitoring only. Built-in bias tee powers LNB via coax.
None	Simulation	`"simulate"`	Full software simulation, no hardware required

Zynq7020 + AD9363 Wiring (Recommended)

TX1 port → F-to-SMA → MAIN F port (TX injection, no bias tee)
RX1 port → F-to-SMA → SEC F port  (receive, bias tee here powers LNB)

Connect the Zynq board's physical Ethernet port to your router. The SDR is accessed via libiio over the network — no USB SDR driver issues, works from any platform including Android.

HackRF One Port Clarification

The HackRF has two SMA connectors. Many people misidentify them:

ANT — your radar RF connection. Handles both TX and RX internally.
CLKOUT — 10 MHz reference clock output only. Not an RF signal port.

Shopping List

Essential

Item	Notes	Price
Winegard Carryout Anser GM-5000	Salvage yards, RV surplus, Facebook Marketplace	$5–40
Zynq7020+AD9363 SDR board	eBay, search "Zynq7020 AD9363 SDR", libiio/Pluto compatible	~$145
F-to-SMA adapters (×2)	Female F to Male SMA	~$10
DTECH RS232-to-RS485 converter	Specifically DTECH brand	~$12
RJ-25 6-pin phone cord	Must be 6-conductor, NOT standard RJ-11	~$5
USB-to-Serial cable	Any brand	~$10
Torx screwdriver set	T10, T15 for inner dome	~$8

Item	Notes	Price
RTL-SDR V4	Built-in bias tee powers LNB via SEC port	~$35
10 dB SMA attenuator	Inline on TX path, protects SDR from close-range reflections	~$5

Future Upgrade

Item	Notes	Price
10 GHz Gunn oscillator	eBay "10GHz Gunn oscillator" — replaces reverse-drive method, dramatically extends range	~$20–60

Bias Tee (choose one)

Option A — RTL-SDR V4 (recommended): Connect to SEC port, enable bias tee in software. Powers LNB automatically.

Option B — Internal build: Solder a 100µH inductor and 100pF capacitor inline at the LNB coax junction inside the dome. ~$2 in parts, permanently integrated.

Option C — External: RTL-SDR brand bias tee inline on the SEC coax. ~$12.

Software Stack

Architecture

portable_radar/
├── run.py              Entry point, elevation prompt, launches stack
├── config.py           All settings in one place
├── app.py              Flask web server, /api/telemetry endpoint
├── radar_scanner.py    Main scan loop thread
├── motor.py            RS-485 motor control, paced sweep, position verify
├── sdr.py              SDR hardware abstraction (HackRF/Pluto/RTL-SDR/Sim)
├── gps.py              NMEA GPS parser, speed detection, transit mode
├── recorder.py         Session recording (run alongside main stack)
├── replay.py           Generates standalone HTML replay from session file
├── simplify_maps.py    One-time GeoJSON optimization (run once before first use)
├── lora_bridge.py      LoRa alert uplink via Heltec V4 (optional)
├── static/
│   ├── indiana_counties.geojson
│   └── indiana_roads.geojson
└── templates/
    └── index.html      Live radar PPI display

Installation (Linux/Ubuntu/Debian)

# System dependencies
sudo apt install python3-pip python3-numpy rtl-sdr \
     soapysdr-tools soapysdr-module-hackrf gnuradio \
     gqrx-sdr hamlib-utils

# Python dependencies
pip install flask pyserial gpsd-py3

# Clone this repo
git clone https://github.com/Koakno/Small-portable-weather-radar-Dome
cd Small-portable-weather-radar-Dome/portable_radar

# Optimize map files (run once before first use)
python3 simplify_maps.py

# Run
python3 run.py

Installation (Termux / Android)

pkg install python python-numpy
pip install --break-system-packages pyserial flask

# If python3 and numpy version mismatch:
python3.14 run.py  # use whichever version numpy installed for

Tested on Samsung Galaxy S10+ via Termux. Knox limits direct USB SDR access — use the Zynq board's physical Ethernet port via WiFi router instead.

Configuration

Edit config.py before running:

SDR_TYPE    = "pluto"         # hackrf / pluto / rtlsdr / simulate
SERIAL_PORT = "/dev/ttyUSB0"  # RS-485 adapter port
GPS_PORT    = "/dev/ttyACM0"  # GPS device port
MANUAL_LAT  = 40.4864         # Fallback if no GPS
MANUAL_LON  = -86.1336

TARGET_SWEEP_SECONDS   = 18   # Full 360° sweep duration (slower = more accurate)
TRANSIT_MODE_SPEED_MPH = 5.0  # Above this, dish locks forward while driving

Running

python3 run.py

On startup you will be prompted for the current dish elevation:

  Elevation Configuration
  ========================
  Elevation motor: NOT DETECTED (manual mode)

  Enter current dish elevation (degrees):
    5°  — shallow, best long range storm detection
   15°  — moderate, good general use
   30°  — steep, useful close to a storm

  Elevation > 10
  [OK] Fixed elevation: 10°
       Azimuth correction: -4.0° applied to all returns

The software applies an automatic azimuth correction to compensate for the offset dish geometry coupling elevation into azimuth. Open your browser to http://localhost:5000 or access remotely via your Cloudflare tunnel.

Features

Live Radar Display

Canvas-based PPI (Plan Position Indicator) radar scope
Standard NWS reflectivity color scale (cyan → green → yellow → orange → red → magenta)
Offline Indiana county boundaries and road overlay (no internet required)
Real-time sweep line animation at 60fps
Auto-refresh telemetry every 200ms
Accessible on any device via local WiFi or Cloudflare tunnel

Alert System

Four-tier auditory and visual alert system:

Tier	Name	Trigger	Audio
1	INFO	Any precipitation detected	Single chime
2	CAUTION	Storm core in range	Double chime
3	WARNING	Supercell characteristics	Triple beep
4	DANGER	Debris ball / return within 5 km	Rapid alarm

Alerts require 2 consecutive sweep confirmations before triggering (reduces false positives). 30-second cooldown between repeated same-tier alerts.

Transit Mode

GPS speed is monitored continuously. Above TRANSIT_MODE_SPEED_MPH (default 5 mph):

Dish locks to azimuth 0 (forward, toward storm while driving)
Full sweep suspended
Forward-looking returns still captured and displayed
Mode indicator on web display changes to orange TRANSIT

Below threshold, full azimuth sweeps resume automatically.

Session Recording and Replay

# Record a chase session (run in second terminal alongside main stack)
python3 recorder.py

# Generate standalone replay (no server needed)
python3 replay.py sessions/session_2026-06-29_143210.json

The replay generates a single self-contained HTML file with all session data embedded. VCR-style controls: play/pause, step, scrub, speed selector (0.5x–5x). Opens automatically in your browser. A CSV export is generated alongside the JSON for sharing with NWS/NOAA or other researchers.

Heltec V4 GPS + LoRa Bridge (Optional)

The heltec_gps_lora_bridge.ino sketch turns a Heltec WiFi LoRa 32 V4 into a bidirectional bridge:

GPS uplink: streams NMEA sentences from an attached GPS module over USB — laptop sees it as a standard USB GPS receiver, no special drivers
LoRa downlink: receives ALERT:<tier>:<message> commands from the laptop over the same USB serial line and transmits them over LoRa 915 MHz to any receiver in range
OLED display: shows live coordinates, fix status, satellite count, speed, and transit mode indicator

The V3 board is also supported (different GPIO pins, no dedicated GNSS connector — wire a GPS module to GPIO33/34 instead).

Deployment

North Alignment

Important: Azimuth 0 on the dome corresponds to approximately North, assuming the dish is mounted facing the front of the vehicle. Align your vehicle to North before deploying using a compass app on your phone. Built-in vehicle compasses typically only indicate the nearest 45° cardinal direction — a phone compass app gives actual degree readings and is sufficient for alignment at this beamwidth.

Elevation and Azimuth Coupling

The Carryout Anser's offset dish geometry means changing elevation also shifts the effective beam azimuth. The software compensates automatically — enter your current elevation at startup and the azimuth correction is applied to every logged return. Default coupling coefficient is 0.4°/degree of elevation (empirically adjustable in run.py).

Vehicle Mounting

The dome mounts to a roof rack via its standard base. Orient so the MAIN/SEC F connectors face rearward — this places the motor's natural 0° position toward the front of the vehicle. Set elevation before mounting (check degree markings on dome base). Stow the dome (lay flat) when driving at highway speed — rated 35 mph maximum wind loading.

Field Deployment Checklist

Park, orient vehicle North using compass app
Set dish elevation using base markings, lock in place
Connect power (2-pin connector), coax (MAIN and SEC), RS-485 (RJ-25)
Run python3 run.py, enter elevation when prompted
Open browser to localhost:5000 or radar.koakno.com
Monitor PPI display — alerts will sound if storm signatures detected

Expected Performance

Detection Range

Target	Reverse-drive LNB (~1-5mW)	With Gunn oscillator TX (~4W)
Heavy downpour	3–8 km	15–40 km
Supercell hail core	8–15 km	30–60 km
Tornado debris ball	10–20 km	20–40 km
Moderate rain	1–3 km	5–15 km

Scan Performance

Mode	Time
Full 360° sweep	~18 seconds (paced for accuracy)
90° sector scan	~4.5 seconds
NEXRAD comparison	Updates every 4–6 minutes

Sweep timing is deliberately paced slower than the motor's mechanical maximum (~10 seconds) to allow position verification at each step, ensuring logged returns correspond to confirmed dish positions rather than commanded positions.

Licensing

Transmitting at 10.4 GHz requires a minimum Technician class amateur radio license in the US. The 3cm band (10.0–10.5 GHz) is an amateur allocation.

35 question multiple choice exam
~$15 exam fee
Study free at HamStudy.org
Most people pass with 1–2 weeks of casual study
Also enables APRS position reporting and VHF/UHF voice comms with other chasers

Safety

⚠️ This system is for observing severe weather from a safe distance. Never attempt to intercept or approach a tornado. Always maintain a viable escape route. Monitor NWS warnings alongside your own radar data. Your radar provides local situational awareness — NWS provides the authoritative forecast and warning.

⚠️ The dome is rated to 35 mph wind loading. Stow it when driving at highway speed. Do not operate during hail.

Credits

SaveItForParts — whose Carryout-Radio-Telescope project reverse engineered the GM-5000 RS-485 motor control protocol and proved the concept of using this dome as an RF imager. This project would not exist without that work.

Resources

Resource	Link
GNU Radio	gnuradio.org
RTL-SDR drivers	rtl-sdr.com
HamStudy (license exam)	hamstudy.org
NWS Indianapolis SKYWARN	weather.gov/ind/skywarn
Spotter Network	spotternetwork.org

Version History

Version	Date	Notes
v1.0	2026-06-22	Initial hardware confirmation and signal chain documentation
v2.0	2026-07-05	Full modular software stack, Flask web interface, offline Indiana map, alert system, GPS integration, session recording, replay system, LoRa bridge, transit mode, elevation correction, Termux compatibility confirmed

Built in Kokomo, Indiana — tornado country. If this helps one person get better warning of an incoming storm it was worth building.

Note - this project was mostly human-made and Hands-On, AI was used in the involvement of cleaning up code that was messy and polishing it up, AI had no part and designing building or fabricating the code or Hardware used, this was all done of my Accord because I nearly got killed by a tornado that nextrad could not see

Small-portable-weather-radar-Dome