Updated Band Switching
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The Portsdown band switching was updated in July 2021 to enable the selection of 16 bands.
By default, 7 of these bands are for direct transmission (without a transverter), and 9 are allocated for transverter use.
Against each of the 16 bands, the following settings are stored:
- A Label that is displayed on the band select button and the Contest card for that band.
- A transverter (transmit) local oscillator frequency, so that both the IF drive frequncy and the final transmitted frequency can be displayed on the Portsdown Menus.
- Settings for the 4 GPIO lines, which are available on the Raspberry Pi GPIO header, the LimeSDR FPGA GPIO and the DATV Express GPIO pins.
- An attenuation level for an external attenuator to set the transmit drive level.
- The transmit power level for a DATV Express card
- The Lime Gain for a LimeSDR
- The Pluto output power level
- The Contest numbers for the band
- The receive LO frequency for an ADF4351-based receive converter (primarily for 50 and 70 MHz operation)
- Enable/disable for a LimeRFE PA
- The TX port to be used for a LimeRFE (not yet implemented)
- The Receive Attenuation for a LimeRFE (not yet implemented)
The factory default settings are shown below. Note that the d0 to t8 designation and the band index are both used internally in the Portsdown and cannot be changed.
| Usage | Band name | LO Frequency | GPIO Binary | GPIO Decimal | Band Designation and index |
|---|---|---|---|---|---|
| 50 MHz Direct | 50_MHz | 0 | 1 0 0 0 | 8 | d0 14 |
| 71 MHz Direct | 71_MHz | 0 | 0 0 0 0 | 0 | d1 0 |
| 146 MHz Direct | 146_MHz | 0 | 0 0 0 1 | 1 | d2 1 |
| 437 MHz Direct | 70_cm | 0 | 0 0 1 0 | 2 | d3 2 |
| 1255 MHz Direct | 23_cm | 0 | 0 0 1 1 | 3 | d4 3 |
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