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Merge branch 'master' of https://github.com/mc-hamster/Meshtastic-device

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docs/radio-settings.md
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@ -31,11 +31,56 @@ Channel zero starts at 903.08 MHz center frequency.
## Data-rates
Various data-rates are selectable when configuring a channel and are inversely proportional to the theoretical range of the devices:
### About
Various data-rates are selectable when configuring a channel and are inversely proportional to the theoretical range of the devices.
Considerations:
* Spreading Factor - How much we "spread" our data over time.
* * Each step up in Spreading Factor dobules the airtime to transmit.
* * Each step up in Spreading Factor adds about 2.5db extra link budget.
* Bandwidth - How big of a slice of the spectrum we use.
* * Each doubling of the bandwidth is almost 3db less link budget.
* * Bandwidths less than 31 may be unstable unless you have a high quality Crystal Ossilator.
* Coding Rate - How much redundency we encode to resist noise.
* * Increasing coding rate increases reliability while decrasing data-rate.
* * 4/5 - 1.25x overhead
* * 4/6 - 1.5x overhead
* * 4/7 - 1.75x overhead
* * 4/8 - 2x overhead
### Pre-Defined
We have four predefined channels. These are the most common settings and have been proven to work well:
| Channel setting | Alt Channel Name | Data-rate | SF / Symbols | Coding Rate | Bandwidth |
|:---------------------------|:-----------------|:---------------------|:-------------|:------------|:----------|
| Short range (but fast) | Short Fast | 21.875 kbps | 7 / 128 | 4/5 | 125 |
| Medium range (but fast) | Medium | 5.469 kbps | 7 / 512 | 4/5 | 500 |
| Long range (but slower) | Long Alt | 0.275 kbps | 9 / 512 | 4/8 | 31 |
| Very long range (but slow) | Long Slow | 0.183 kbps (default) | 12 / 4096 | 4/8 | 125 |
### Custom Settings
You may want to select other channels for your usage. The other settings can be set by using the Python API.
> meshtastic --setchan spread_factor 10 --setchan coding_rate 8 --setchan bandwidth 125
Some example settings:
| Data-rate | SF / Symbols | Coding Rate | Bandwidth | Note |
|:---------------------|:-------------|:------------|:----------|:-----|
| 3.125 kbps | 8 / 256 | 4/5 | 125 | |
| 1.953 kbps | 8 / 256 | 4/8 | 125 | |
| 1.343 kbps | 11 / 2048 | 4/8 | 512 | |
| 1.099 kbps | 9 / 512 | 4/8 | 125 | |
| 0.814 kbps | 10 / 1024 | 4/6 | 125 | |
| 0.610 kbps | 10 / 1024 | 4/8 | 125 | |
| 0.488 kbps | 11 / 2048 | 4/6 | 125 | |
| 0.336 kbps | 11 / 2048 | 4/8 | 125 | |
| 0.092 kbps | 12 / 4096 | 4/8 | 62 | |
| 0.046 kbps | 12 / 4096 | 4/8 | 31 | Twice the range of "Long Slow" |
| Channel setting | Data-rate |
|----------------------------|----------------------|
| Short range (but fast) | 21.875 kbps |
| Medium range (but fast) | 5.469 kbps |
| Long range (but slower) | 0.275 kbps |
| Very long range (but slow) | 0.183 kbps (default) |