This is a public announcement regarding high speed data tests of Tobias, OE3TEC on the two meter band „DATA“ segment between 144.491MHz and 144.975MHz. Most commonly used frequencies are 144.880MHz and 144.850MHz +/- QRM. The test station will change frequency if other stations are noticed on the frequency during testing. Maximum occupied bandwidth is ~38kHz but will always stay below 40kHz.
Various digital modulations schemes (QPSK, 16-QAM, 64-QAM) are tested at three different data rates (28300, 14150, 7080 Symbols per Second). This results in a peak goodput datarate of ~100kbits/s.
The callsign is encoded in the transmitted data frames. A CW beacon may be added at higher power tests to identify the station and avoid false flags as „band intruder“.
The tests include mobile and stationary tests with LOS and NLOS paths. These are needed to characterize ISI and fading behavior of real world applications on the two meter band. A single test can require a transmitter to be active for up to 30 minutes. Especially mobile fading and NLOS tests will require a higher transmit power. The mean power stays below 300mW. The peak power can be up to 10dB higher.
Signal at 144.850MHz in this screenshot is a typical test transmission from OE3TEC’s high speed data tests.
The test transmission can also have a steady bandwidth as visible here on 144.850MHz. This is the case for tests which only involve a single symbol rate.
For questions contact Tobias, OE3TEC via the E-Mail address noted on his QRZ.com page.
