![Aircraft radio telephony transmitter, complete with round valve and microphone, 1915 | Science Museum Group Collection Aircraft radio telephony transmitter, complete with round valve and microphone, 1915 | Science Museum Group Collection](https://coimages.sciencemuseumgroup.org.uk/images/263/821/medium_1935_0618__0002_.jpg)
Aircraft radio telephony transmitter, complete with round valve and microphone, 1915 | Science Museum Group Collection
![Aircraft radio telephony transmitter together with microphone, less Round valve | Science Museum Group Collection Aircraft radio telephony transmitter together with microphone, less Round valve | Science Museum Group Collection](https://coimages.sciencemuseumgroup.org.uk/images/491/565/medium_SMG00305644.jpg)
Aircraft radio telephony transmitter together with microphone, less Round valve | Science Museum Group Collection
![Aircraft radio telephony transmitter, complete with round valve and microphone, 1915 | Science Museum Group Collection Aircraft radio telephony transmitter, complete with round valve and microphone, 1915 | Science Museum Group Collection](https://coimages.sciencemuseumgroup.org.uk/images/263/820/medium_1935_0618__0001_.jpg)
Aircraft radio telephony transmitter, complete with round valve and microphone, 1915 | Science Museum Group Collection
![Flying High and Clear: How Aviation Revolutionized by the Radio Telephony Restricted RTR License | by Wingsss college of aviation and technology | Medium Flying High and Clear: How Aviation Revolutionized by the Radio Telephony Restricted RTR License | by Wingsss college of aviation and technology | Medium](https://miro.medium.com/v2/resize:fit:940/1*TpkP3riQxV6BePfirC_khg.png)
Flying High and Clear: How Aviation Revolutionized by the Radio Telephony Restricted RTR License | by Wingsss college of aviation and technology | Medium
![Aircraft radio telephony transmitter together with microphone, less Round valve | Science Museum Group Collection Aircraft radio telephony transmitter together with microphone, less Round valve | Science Museum Group Collection](https://coimages.sciencemuseumgroup.org.uk/images/276/225/medium_1935_0618__0002_.jpg)
Aircraft radio telephony transmitter together with microphone, less Round valve | Science Museum Group Collection
![R.T.R(A) Exams & License | Complete Guide | Radio Telephony Restricted | Golden Epaulettes Aviation - YouTube R.T.R(A) Exams & License | Complete Guide | Radio Telephony Restricted | Golden Epaulettes Aviation - YouTube](https://i.ytimg.com/vi/b2bqTALP8dU/maxresdefault.jpg)