Update README

README.md

@@ -10,7 +10,7 @@ This software is licenced under the GPL v2 and is intended for amateur and educa
 
 - Supported modes: D-Star, DMR, Yaesu Fusion, P25 Phase 1 and NXDN
 - Automatic mode detection (scanning)
-- G4KLX software suite: [MMDVMHost](https://github.com/g4klx/MMDVMHost), [ircDDBGateway](https://github.com/dl5di/OpenDV), [YSFGateway](https://github.com/g4klx/YSFClients), [P25Gateway](https://github.com/g4klx/P25Clients) and [DMRGateway](https://github.com/g4klx/DMRGateway)
+- G4KLX software suite: [MMDVMHost](https://github.com/g4klx/MMDVMHost), [ircDDBGateway](https://github.com/dl5di/OpenDV), [YSFGateway](https://github.com/g4klx/YSFClients), [P25Gateway](https://github.com/g4klx/P25Clients), [DMRGateway](https://github.com/g4klx/DMRGateway) and [MMDVMCal](https://github.com/g4klx/MMDVMCal), 
 - Bands: 144, 220, 430 and 900 MHz (VHF requires external inductor)
 - Status LEDs (PTT, COR and digital modes)
 - Serial repeater port for Nextion displays
@@ -23,6 +23,8 @@ This software is licenced under the GPL v2 and is intended for amateur and educa
 
 The ADF7021 (or RF7021SE module) must operate with a 14.7456 MHz TCXO and with at least 2 ppm of frequency stability. You could use also 12.2880 MHz TCXO, but this frequency configuration has less testing. Any other TCXO frequency is not supported.
 
+Please set TXLevel=50 in MMDVM.ini to configure default deviation levels for all modes. You could change this value and other TXLevel paramenters to change deviation levels. Use [MMDVMCal](https://github.com/g4klx/MMDVMCal) to check DMR deviation level and TX frequency offset with calibrated test equipment.
+
 The jumper wire to CLKOUT in RF7021SE module is not longer required for lastest MMDVM_HS firmware. But CE pin connection of ADF7021 is required for proper operation of ZUMspot.
 
 Be aware that some Blue Pill STM32F103 board are defectives. If you have trouble with USB, please check this [link](http://wiki.stm32duino.com/index.php?title=Blue_Pill).