# RSSI Mapping for Direction Finding

Use receive-only signal-strength readings to sketch a direction clue, compare angles, and explain uncertainty before making any field claim.

## Outcome
Record angle/RSSI pairs, plot a strongest lobe, and explain what the reading suggests without claiming exact source location.

## Safe first step
Use only lawful receive-only readings from your own test source or a signal you are allowed to monitor; do not track people or interfere with equipment.

## Ladder steps
### 1. Name the test source
RSSI only makes sense when the source, receiver, antenna, and legal boundary are named.

Check: Your note says what you are allowed to receive and why the test is receive-only.

### 2. Record readings by angle
Turn the antenna or receiver in known angle steps and write the RSSI value for each direction.

Check: Your table includes angle, RSSI, location, antenna orientation, and time.

### 3. Find the strongest lobe
The largest reading is a direction clue, but reflections and antenna pattern can create false peaks.

Check: Your plot marks the strongest reading and a confidence note.

### 4. Repeat before deciding
A second rotation checks whether the peak is stable or just a noisy moment.

Check: Your conclusion says what repeated, what changed, and what remains uncertain.

## Examples
### Compare readings around a circle
```sh
0 deg:-72, 45 deg:-65, 90 deg:-58, 135 deg:-63
```
Expected signal: -58 dBm at 90 degrees is the strongest clue in this sample

Caution: Do not treat one sweep as exact location proof.

### Pick a first bearing hypothesis
```sh
strongest_angle = angle_with_max_rssi(readings)
```
Expected signal: The chosen angle points toward the strongest measured signal

Caution: RSSI peaks can be distorted by reflections, body position, and antenna pattern.

### Check repeatability
```sh
repeat_sweep -> compare_peak_angles -> write_uncertainty
```
Expected signal: A stable peak across sweeps deserves more confidence than a one-off jump

Caution: Stop if the task becomes tracking people, private devices, or unauthorized systems.

## Common traps
- Forgetting that -52 dBm is stronger than -80 dBm.
- Treating RSSI as exact distance or exact location.
- Ignoring reflections from buildings, vehicles, benches, or your own body.
- Using the method to track people, private devices, public-safety signals, or anything you are not allowed to monitor.
- Changing transmit settings instead of improving the receive-only measurement note.

## Practice task
Enter eight angle/RSSI pairs in the widget, copy the Markdown note, then write whether the strongest direction is a clean peak, a broad lobe, or too noisy to trust.

## Next steps
- Save the Obsidian note with [[RSSI]], [[Direction Finding]], [[Antenna Pattern]], [[Receive-Only Practice]], [[RF Safety]], and [[Lawful Use]] backlinks.
- Review the source video cards and vote on which one best explains repeated measurements.
- Use the stepper antenna sweep route when manual rotation is too inconsistent.
- Try the antenna-length math route before changing antennas.
- Use bearing-lines and triangulation only after you can explain single-station uncertainty.

## Related
- [Radio and Signals topic group](/topics/rf/)
- [Packet radio receive-first path](/learn/rf/packet-radio-baofeng-aprs-first-pass/)
- [Stepper antenna sweep for direction finding](/learn/rf/stepper-antenna-sweep-for-direction-finding/)
- [Vectors for direction arrows](/learn/vectors-for-maker-projects/)
- [Angles and rotation](/learn/trigonometry-for-rotation-and-layout/)
- [Make an Obsidian project note](/learn/make-an-obsidian-project-note/)
- [Turn a source video into notes](/video-notes/)
- [Review Anki-compatible decks](/decks/)

## Obsidian backlinks

Use these wiki links to connect this note inside a local maker vault:

- [[TopicLadder]]
- [[Maker Learning]]
- [[RSSI Mapping for Direction Finding]]
- [[Radio and Signals]]
- [[rf]]
- [[receive-first]]
- [[Name the test source]]
- [[Record readings by angle]]
- [[Find the strongest lobe]]
- [[Repeat before deciding]]
- [[Radio and Signals topic group]]
- [[Packet radio receive-first path]]

## Source and next routes

Source: https://topicladder.com/learn/rf/rssi-mapping-for-direction-finding/

- [Radio and Signals topic group](/topics/rf/)
- [Packet radio receive-first path](/learn/rf/packet-radio-baofeng-aprs-first-pass/)
- [Stepper antenna sweep for direction finding](/learn/rf/stepper-antenna-sweep-for-direction-finding/)
- [Vectors for direction arrows](/learn/vectors-for-maker-projects/)
- [Angles and rotation](/learn/trigonometry-for-rotation-and-layout/)
- [Make an Obsidian project note](/learn/make-an-obsidian-project-note/)
- [Turn a source video into notes](/video-notes/)
- [Review Anki-compatible decks](/decks/)