These apps can be installed on any Android device.
For Callsign lookup
Callsign DB: Price- Free
Description: It is a basic database where a user can lookup their own or someone else's callsign and it will give basic information on the callsign and about the user.
Amatuer Radio Call Log: Price- Free
Description: It is a basic call log that lets the user input data about others and also functions as an easy look up for callsigns.
For Ham Radio Communication
QSL Mobile Ham Radio: Price- $2.99
Description: It allows a Ham Radio operator on the go to locate nearby repeaters.
HAM Radio Ionosphere Status: Price- Free
Description: It is an easy app that allows a Ham Radio operator to receive recent information on the Sun and solar cycle.
HamSatDroid: Price- Free
Description: It allows Radio operators to locate satellite pass prediction.
APRSdriod: Price- $4.49
Description: It is an APRS application for Amateur Radio (HAM) operators to allow reporting of your position and as well sending and recieving messages. It also lists nearby stations on a list or a map.
Ham Radio Practice Tests
Ham Radio: Price- $2.50
Description: It is a glossary of Amateur radio terms and acronyms. It is great for those who are interested in Ham Radio and those who are preparing for radio license tests.
Amateur Radio Exam 1.0: Price- Free
Description: It is an app that allows one to practice for all of the license and radio exams.
**There are more applications available than the ones listed above but these are just to get you started.**