# Specification

### Specification&#x20;

| <p><br></p>                          | P900                                                                                                                     | P840                                                                                  | P400-C1S                                                                              |
| ------------------------------------ | ------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------- |
| Frequency Range                      | 902 to 928 MHz                                                                                                           | 840 to 845 MHz                                                                        | 410 to 480 MHz                                                                        |
| Transmit Power (Software Adjustable) | <p>100mW to 1W (20-30dBm) <br></p>                                                                                       | 100mW to 1W (20-30dBm)                                                                | 100mW to 1W (20-30dBm)                                                                |
| Link Rate                            | Up to 276 kbps                                                                                                           | Up to 345 kbps                                                                        | Up to 345 kbps                                                                        |
| Serial Baud Rate                     | Up to 230.4kbps asynchronous                                                                                             | 300 bps to 230 kbps                                                                   | 300 bps to 230 kbps                                                                   |
| Spreading Method                     | Frequency Hopping Spread Spectrum (FHSS)                                                                                 | <p>Frequency Hopping/Fixed Frequency,<br>GMSK, 2GFSK, 4GFSK, QPSK</p>                 | <p>Frequency Hopping,<br>GMSK, 2GFSK, 4GFSK, QPSK</p>                                 |
| Operating Modes                      | <p>Mesh, Point-to-Point, Point-to-Multipoint, Store and Forward,<br>Auto Routing, Self Healing, Packet Routing Modes</p> | <p>Point-to-Point, Point-to-Multipoint,<br>store & Forward Repeater, Peer-to-Peer</p> | <p>Point-to-Point, Point-to-Multipoint,<br>store & Forward Repeater, Peer-to-Peer</p> |
| Input Voltage                        | <p>DC7\~35V<br>(4-position JST-GH)</p>                                                                                   | <p>C7\~35V<br>(4-position JST-GH)</p>                                                 | <p>C7\~35V<br>(4-position JST-GH)</p>                                                 |
| Power Consumption                    | <p>Sleep < 1mA<br>dle 3.5mA<br>Rx: 45mA to 98mA<br>Tx : 1000mA to 1400mA</p>                                             | <p>Sleep < 1mA<br>dle 3.5mA<br>Rx: 45mA to 98mA<br>Tx : 1000mA to 1400mA</p>          | <p>Sleep < 1mA<br>Idle 20mA<br>Rx: 45mA to 98mA<br>Tx Peak: 2A</p>                    |
| Error Detection                      | 32 bits of CRC, ARQ                                                                                                      | 32 bits of CRC, ARQ                                                                   | 32 bits of CRC, ARQ                                                                   |
| Antenna Gain                         | 5dBi                                                                                                                     | 5dBi                                                                                  | 5dBi                                                                                  |
| Weight                               | <p>44g (without antenna) <br> 71g (with antenna)</p>                                                                     | <p>44g (without antenna) <br> 71g (with antenna)</p>                                  | <p>44g (without antenna) <br>67g (with antenna)</p>                                   |
| Weight (V2)                          | <p>51g (without antenna) <br> 81g (with antenna)</p>                                                                     | NA                                                                                    | <p>51g (without antenna) <br> 76g (with antenna)</p>                                  |

### P400 Frequency 410 to 480 MHz (Frequency Hopping)

| Rate (kbps) | Power (W) | Sensitivity (dBm) | Bandwidth (kHz) | Regulatory |
| ----------- | --------- | ----------------- | --------------- | ---------- |
| 56.0        | 1         | -113              | 60.0            | None\*     |
| 115.2       | 1         | -109              | 150.0           | None\*     |
| 172.8       | 1         | -108              | 180.0           | None\*     |
| 230.4       | 1         | -106              | 230.0           | None\*     |
| 276.4       | 1         | -105              | 230.0           | None\*     |
| 345.0       | 1         | -103              | 400.0           | None\*     |

### P840 Sensitivity (Frequency Hopping)

<table><thead><tr><th width="147"></th><th width="115"></th><th width="160"></th><th></th></tr></thead><tbody><tr><td>Rate (kbps)</td><td>Power (W)</td><td>Sensitivity (dBm)</td><td>Bandwidth (kHz)</td></tr><tr><td>19.2</td><td>1</td><td>-116</td><td>25</td></tr><tr><td>56</td><td>1</td><td>-113</td><td>60</td></tr><tr><td>115.2</td><td>1</td><td>-109</td><td>150</td></tr><tr><td>172.8</td><td>1</td><td>-108</td><td>180</td></tr><tr><td>230.4</td><td>1</td><td>-106</td><td>230</td></tr><tr><td>276.4</td><td>1</td><td>-105</td><td>280</td></tr><tr><td>345</td><td>1</td><td>-103</td><td>400</td></tr></tbody></table>

### P900 Sensitivity (@10-4)

| Rate (kbps) | Sensitivity (dBm) |
| ----------- | ----------------- |
| 57.6        | -114              |
| 115.2       | -112              |
| 172.8       | -109              |
| 230.4       | -107              |


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.holybro.com/radio/microhard-radio/specification.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
