Difference between revisions of "FrSky DHT RSSI configuration"
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To get an idea of how well the different set of antennas would perform, I swapped the antennas one by one and recorded the Tx and Rx values from the configuration application. | To get an idea of how well the different set of antennas would perform, I swapped the antennas one by one and recorded the Tx and Rx values from the configuration application. | ||
All the tests where performed indoors with antennas about 10 meters apart. | All the tests where performed with a FPV VTX 1180 MHz running next to the receiver and everything was done indoors with antennas about 10 meters apart in separate rooms. | ||
* Transmitter: FrSky 2dbi rubber duck antenna | * Transmitter: FrSky 2dbi rubber duck antenna | ||
** Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: ''' | ** Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: '''37''' - RSSI Rx: '''66''' | ||
** Receiver: Dipole 33 mm wire antenna - RSSI Tx: ''' | ** Receiver: Generic Alfa 5dbi rubber duck antenna - RSSI Tx: '''52''' - RSSI Rx: '''71''' | ||
** Receiver: Dipole 30 mm wire antenna - RSSI Tx: ''' | ** Receiver: Dipole 33 mm wire antenna - RSSI Tx: '''41''' - RSSI Rx: '''74''' | ||
** Receiver: Generic | ** Receiver: Dipole 32 mm wire antenna - RSSI Tx: '''49''' - RSSI Rx: '''73''' | ||
* Transmitter: Generic 2.4 GHz 14 dBi patch antenna | ** Receiver: Dipole 30 mm wire antenna - RSSI Tx: '''62''' - RSSI Rx: '''78''' | ||
** Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: ''' | ** Receiver: Dipole 29 mm wire antenna - RSSI Tx: '''54''' - RSSI Rx: '''74''' | ||
** Receiver: Dipole 33 mm wire antenna - RSSI Tx: ''' | ** Receiver: Dipole 29 mm wire antenna - RSSI Tx: '''54''' - RSSI Rx: '''74''' | ||
** Receiver: Dipole 30 mm wire antenna - RSSI Tx: ''' | ** Receiver: Dipole 27 mm wire antenna - RSSI Tx: '''51''' - RSSI Rx: '''74''' | ||
** Receiver: Generic | ** ''Receiver: Generic Alfa 2.4 GHz 14 dBi patch antenna'' - RSSI Tx: '''73''' - RSSI Rx: '''79''' - ''control'' | ||
* Transmitter: Generic Alfa 5dbi rubber duck antenna | |||
** Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: '''37''' - RSSI Rx: '''54''' | |||
** Receiver: Dipole 33 mm wire antenna - RSSI Tx: '''52''' - RSSI Rx: '''78''' | |||
** Receiver: Dipole 32 mm wire antenna - RSSI Tx: '''41''' - RSSI Rx: '''74''' | |||
** Receiver: Dipole 30 mm wire antenna - RSSI Tx: '''57''' - RSSI Rx: '''77''' | |||
** Receiver: Dipole 29 mm wire antenna - RSSI Tx: '''49''' - RSSI Rx: '''74''' | |||
** Receiver: Dipole 27 mm wire antenna - RSSI Tx: '''54''' - RSSI Rx: '''68''' | |||
* Transmitter: Generic Alfa 2.4 GHz 14 dBi patch antenna | |||
** Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: '''73''' - RSSI Rx: '''83''' | |||
** Receiver: Generic 5dbi rubber duck antenna - RSSI Tx: '''78''' - RSSI Rx: '''87''' | |||
** Receiver: Dipole 33 mm wire antenna - RSSI Tx: '''74''' - RSSI Rx: '''83''' | |||
** Receiver: Dipole 32 mm wire antenna - RSSI Tx: '''73''' - RSSI Rx: '''82''' | |||
** Receiver: Dipole 30 mm wire antenna - RSSI Tx: '''74''' - RSSI Rx: '''81''' | |||
** Receiver: Dipole 29 mm wire antenna - RSSI Tx: '''74''' - RSSI Rx: '''82''' | |||
** Receiver: Dipole 27 mm wire antenna - RSSI Tx: '''74''' - RSSI Rx: '''82''' | |||
* Transmitter: Generic Dealextreme 2.4 GHz 14 dBi flat panel antenna | |||
** Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: '''73''' - RSSI Rx: '''82''' | |||
** Receiver: Generic 5dbi rubber duck antenna - RSSI Tx: '''78''' - RSSI Rx: '''85''' | |||
** Receiver: Dipole 33 mm wire antenna - RSSI Tx: '''73''' - RSSI Rx: '''81''' - ''holding the panel 90 degrees to the side to match the vertical dipole polarity'' | |||
** Receiver: Dipole 32 mm wire antenna - RSSI Tx: '''73''' - RSSI Rx: '''82''' | |||
** Receiver: Dipole 30 mm wire antenna - RSSI Tx: '''72''' - RSSI Rx: '''80''' | |||
** Receiver: Dipole 29 mm wire antenna - RSSI Tx: '''76''' - RSSI Rx: '''83''' | |||
** Receiver: Dipole 27 mm wire antenna - RSSI Tx: '''74''' - RSSI Rx: '''82''' |
Revision as of 22:02, 12 August 2012
The FrSky DHT is a flexible and relatively powerful 2.4 GHz transmitter. The kit comes as a DIY package with an RP-SMA connector which makes it easy to switch antennas. The communication is two-way allowing for both Tx and Rx signal strength indication (RSSI). The ACCST system shifts 80 channels around hundred times per second in the 2.4GHz band, similar to FSK.
I will use an D6FR receiver in this setup.
Serial adapter
To connect to the transmitter you need a USB-to-serial adapter. FrSky makes one with the necessary pin-header.
Plug the black header into the corresponding four pins on the transmitter. Power will be provided by the USB-port.
RSSI configuration
The DHT provides a serial data port for configuration of the alarms for the RSSI and the two analog inputs. Download the 3rd-party configuration program and the required drivers.
Antenna testing
To get an idea of how well the different set of antennas would perform, I swapped the antennas one by one and recorded the Tx and Rx values from the configuration application.
All the tests where performed with a FPV VTX 1180 MHz running next to the receiver and everything was done indoors with antennas about 10 meters apart in separate rooms.
- Transmitter: FrSky 2dbi rubber duck antenna
- Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: 37 - RSSI Rx: 66
- Receiver: Generic Alfa 5dbi rubber duck antenna - RSSI Tx: 52 - RSSI Rx: 71
- Receiver: Dipole 33 mm wire antenna - RSSI Tx: 41 - RSSI Rx: 74
- Receiver: Dipole 32 mm wire antenna - RSSI Tx: 49 - RSSI Rx: 73
- Receiver: Dipole 30 mm wire antenna - RSSI Tx: 62 - RSSI Rx: 78
- Receiver: Dipole 29 mm wire antenna - RSSI Tx: 54 - RSSI Rx: 74
- Receiver: Dipole 29 mm wire antenna - RSSI Tx: 54 - RSSI Rx: 74
- Receiver: Dipole 27 mm wire antenna - RSSI Tx: 51 - RSSI Rx: 74
- Receiver: Generic Alfa 2.4 GHz 14 dBi patch antenna - RSSI Tx: 73 - RSSI Rx: 79 - control
- Transmitter: Generic Alfa 5dbi rubber duck antenna
- Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: 37 - RSSI Rx: 54
- Receiver: Dipole 33 mm wire antenna - RSSI Tx: 52 - RSSI Rx: 78
- Receiver: Dipole 32 mm wire antenna - RSSI Tx: 41 - RSSI Rx: 74
- Receiver: Dipole 30 mm wire antenna - RSSI Tx: 57 - RSSI Rx: 77
- Receiver: Dipole 29 mm wire antenna - RSSI Tx: 49 - RSSI Rx: 74
- Receiver: Dipole 27 mm wire antenna - RSSI Tx: 54 - RSSI Rx: 68
- Transmitter: Generic Alfa 2.4 GHz 14 dBi patch antenna
- Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: 73 - RSSI Rx: 83
- Receiver: Generic 5dbi rubber duck antenna - RSSI Tx: 78 - RSSI Rx: 87
- Receiver: Dipole 33 mm wire antenna - RSSI Tx: 74 - RSSI Rx: 83
- Receiver: Dipole 32 mm wire antenna - RSSI Tx: 73 - RSSI Rx: 82
- Receiver: Dipole 30 mm wire antenna - RSSI Tx: 74 - RSSI Rx: 81
- Receiver: Dipole 29 mm wire antenna - RSSI Tx: 74 - RSSI Rx: 82
- Receiver: Dipole 27 mm wire antenna - RSSI Tx: 74 - RSSI Rx: 82
- Transmitter: Generic Dealextreme 2.4 GHz 14 dBi flat panel antenna
- Receiver: FrSky 2dbi rubber duck antenna - RSSI Tx: 73 - RSSI Rx: 82
- Receiver: Generic 5dbi rubber duck antenna - RSSI Tx: 78 - RSSI Rx: 85
- Receiver: Dipole 33 mm wire antenna - RSSI Tx: 73 - RSSI Rx: 81 - holding the panel 90 degrees to the side to match the vertical dipole polarity
- Receiver: Dipole 32 mm wire antenna - RSSI Tx: 73 - RSSI Rx: 82
- Receiver: Dipole 30 mm wire antenna - RSSI Tx: 72 - RSSI Rx: 80
- Receiver: Dipole 29 mm wire antenna - RSSI Tx: 76 - RSSI Rx: 83
- Receiver: Dipole 27 mm wire antenna - RSSI Tx: 74 - RSSI Rx: 82