Build 3.0.4: Initial transmit support for:
- LSB, USB, AM, Narrow-FM
- Half Duplex
Initially only half-duplex is supported using RX1 and TX1. If possible full duplex will be supported in the future using RX1 / TX2 with the Lime USB (the Lime Mini only supports RX1 and TX1).
Use an external pwer supply (PSU) with the Lime USB when transmitting. The recommended voltage is 8v, more than this is just dissipated as heat.
The recommended rate is 3.072MHz - switching between receive and transmit is fastest when the receive and transmit rates are the same.
RX and TX sample rates are closely tied in the Lime's LMS7 chip. The RX/TX ratio can only be a power of 2 and is also limited by other factors.
The internal modulated IQ data stream rate is 192kHz, the transmit sample rate is fixed at 3.072MHz (192 kHz x 16) on the advice of Lime engineers.
Sample rates which are a power of 2 of the transmit sample rate also enable transmit support: 3.072, 6.144, 12.288 and 24.576 MHz.
Only 3.072MHz is supported for transmit, other rates may be supported later.
Transmit is only supported for 3.072 MHz.
To calibrate the transmitter select TX Calib (see options below)., this will reduce the spur in the centre of the transmission. Currently the transmitter is not automatically calibrated. Some users are reporting improved calibration (spur reduction) when the unit is properly cooled.
The transmitter should be recalibrated when you change band and / or prower level (drive).
Full transmit support information is here [link].