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Nearing end of radio docs

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Ron Hale-Evans 2016-06-02 17:08:09 -07:00
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docs/reference/radio/set-transmit-power.md
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# Set Transmit Power
Sets the transmitter power for ``radio`` communications.
The power can be set to a value between 0 (-30dbm) and 7 (+4dbm).
Make the ``radio`` signal of the micro:bit stronger or weaker.
It can be as weak as `0` and as strong as `7`.
The scientific name for the strength of the ``radio`` signal is
**dBm**, or **decibel-milliwatts**. A signal strength of `0`
can be measured as -30 dBm, and a strength of `7` can be
measured as +4 dBm.
## Range
At power level 7, in an open area without significant interference (coming from WiFi networks or other devices operating on the 2.4 GHz range), you can get a **range of over 70m**.
Indoors (or with additional interference), range will be significantly reduced.
## Important Security Consideration
The functions in the ``radio`` namespace allow the BBC micro:bit to communicate with other micro:bits.
This API does not contain any form of encryption, authentication or authorization. It's purpose is solely for use as a teaching aid to demonstrate how simple communications operates, and to provide a sandpit through which learning can take place.
For serious applications, BLE should be considered a substantially more secure alternative.
```sig
radio.setTransmitPower(1)
```
If your micro:bit is sending with a strength of `7`, and you are in
an open area without many other computers around, the micro:bit signal
can reach as far as 70 meters (about 230 feet).
### Parameters
* ``power`` -- a [number](/reference/types/number) between ``0`` and ``7``.
* a [number](/reference/types/number) between ``0`` and ``7`` that
means how strong the signal is.
### Example
Sets the transmitter power to full power at 7.
This program makes the ``radio`` send at full strength.
```blocks
radio.setTransmitPower(7)