Erhardt, StefanStefanErhardtKurin, ThomasThomasKurinLurz, FabianFabianLurzWeigel, RobertRobertWeigelKölpin, AlexanderAlexanderKölpin2020-06-242020-06-242019European Microwave Conference, EuMC : 8910691 (2019)http://hdl.handle.net/11420/6422Most modern digital speech codecs are proprietary and do not give insights into their implementations. 'Codec 2' is an open-source codec and opens up the possibility of application-tailored adaptations. In this publication a new 450 bit/s mode is introduced. It includes a pseudo-wideband mode that can be optionally enabled at the receiver without resulting in a higher bit rate. By sorting the codebook vectors a bit error rate of 10-1 is still intelligible. An encoded audio transmission was tested with two low-power Sub-GHz transceivers in the 70 cm amateur radio band achieving a sensitivity of -130 dBm. For proofing the concept, a field test was conducted and compared to a propagation simulation.enopen source softwareradio transceiversSpeech codingvocodersConference Paper10.23919/EuMC.2019.8910691Other