These are some tips:
- Preparation of phonetic language calls such as altitude, speed, altitude and wind directions.
- Manual of radio telephony (102 Pages) by ICAO Doc.9432 will clarify all your doubts about the point no. 1.
- WPC website has sample RTR questions. The key to cracking the calls part is precise phonetic language use. Scribd also has sample questions
- A detailed knowledge of radio aids, navigation tools, electrical terms, and laws like ohm. faraday.joule. Knowledge of GSM and CDMA
- Air regulations for may day and pan calls. 18 Annexes, Various ICAO docs numbers and names. ICAO Conventions
- Books from ICAO manuals and R.K.Bail's book on rtr
I hope this helps! All the best with your rtr!
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