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Update radio-settings.md

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Jm Casler 2021-02-02 23:57:25 -08:00
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docs/radio-settings.md
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@ -31,7 +31,23 @@ 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:
Various data-rates are selectable when configuring a channel and are inversely proportional to the theoretical range of the devices.
Considerations:
* Spreading Factor
* * 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
* * Each doubling of the bandwidth is almost 3db less link budget.
* Coding Rate
* * 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
Predefined Channels:
| Channel setting | Alt Channel Name | Data-rate | SF / Symbols | Coding Rate | Bandwidth |
|:---------------------------|:-----------------|:---------------------|:-------------|:------------|:----------|
@ -40,7 +56,26 @@ Various data-rates are selectable when configuring a channel and are inversely p
| 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 |
Other radio settings can be configured by using the Python API. An easy calculator of other bit rates is:
Other settings can be set by using the Python API.
> meshtastic --set spread_factor 10 --set coding_rate 8 --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" |
An easy calculator of other bit rates is:
[Lora Parameters](https://unsigned.io/understanding-lora-parameters/)