Update readme

README.md

@@ -19,7 +19,7 @@ Other than the assembled PCB, an antenna is required. For a basic quarter wave c
 * For 433 MHz, use a 165mm
 * For 220 MHz band, Use 324mm
 
-If powered by a button cell battery, solder on a [MY-2032-12](https://www.lcsc.com/product-detail/Battery-Connectors_MYOUNG-MY-2032-12_C964833.html) battery connector. Other similar CR2032 holders work as well, but may require trimming the solder leads to fit the footprint.
+If powered by a button cell battery, solder on a [MY-2032-12](https://www.lcsc.com/product-detail/Battery-Connectors_MYOUNG-MY-2032-12_C964833.html) battery connector. Other similar CR2032 holders work as well, but may require trimming the solder leads to fit the footprint. Melt a little solder on the negative battery terminal before soldering on the battery holder to ensure proper electrical contact.
 
 If powered by an external battery (e.g. 1s lipo), connect to the V+ and GND pins. Note that it doesn't have reverse polarity protection, so double check the polarity!
 
@@ -29,16 +29,22 @@ The firmware can be modified and compiled with [STM32CubeIDE](https://www.st.com
 
 The main code is located in `Firmware\Core\Src\main.c`
 
-Programming the firmware can be done with [STM32CubeProg](https://www.st.com/en/development-tools/stm32cubeprog.html) and a cheap UART to USB dongle (Search "ftdi adaptor" and get one of the red dongles 6 pins)
+Programming the firmware can be done with [STM32CubeProg](https://www.st.com/en/development-tools/stm32cubeprog.html) and a cheap UART to USB dongle (If you don't have one, search "FTDI adaptor" and get one of the red dongles with 6 pins)
 
 * Disconnect power
 * Hold down the button
-* Connect the FTDI adaptor to the beacon (make sure Rx goes to Tx and Tx goes to Rx). If unsoldered, hold them at an angle to ensure proper contact.
+* Set UART adaptor to output 5V power with the jumper, though 3.3V should work as well.
+* Connect the UART adaptor to the beacon (make sure Rx->Tx, Tx->Rx, GND->GND and VCC->V+). If unsoldered, hold them at an angle to ensure proper contact as shown below.
 * LED should be continuously ON, indicating it has entered bootloader mode.
 * In STM32CubeProg, select the UART option and port. Then connect to the MCU.
 * In the Erasing & Programming tab, pick the right firmware `Firmware\Debug\rocketbeacon.elf`, and program
 * Cycle power to execute the code.
 
 
+![programming](Images/programming.png)
+
+## Reception and tuning
+Tune your radio to the programmed frequency. Without calibration, the frequency has a tolerance of roughly +/- 5 KHz in the 70 cm band.
+
 ## Configuration
 TODO: Make a little UART configuration interface to set frequency, callsign etc.