RaspDAB/Go on air with the EasyDab board

Latest revision as of 12:07, 16 April 2020

Now we can get the EasyDab v2 board to get on air ! But don't be too enthusiastic and operate it without an antenna or 50 ohm dummy load on the RF output: this could damage the output amplifier ! So connect a 50 ohm coax cable with e.g. short (about 36 cm) vertical antenna.

You may need to create a small subLAN with an extra router, if only to be able to access the web interface of the board only once to set the IP address you plan to use in the future. The first time the board is powered up it will have a default IP address of 192.168.2.4, and you need to be able to access it. So start a PC which is on the same subLAN and start a webbrowser that you point to 192.168.2.4. If the EasyDab board can be reached it should respond by asking for a user ID and Password, which are both 'admin' by default. Once you provide that you should have access to the web interface to control the operation of the board. Do a check to confirm the firmware version of the board is the latest one (see http://tipok.org.ua/node/46 for information on the latest version and to check for any changes since this document was last updated).

The first part of the control page is about the Network Settings. You can set

   IP address : put here the fixed address that you want to use to access the board's web interface in the future;
   netmask : typically 255.255.255.0 for a LAN;
   gateway : the IP address of the device through which other addresses outside the LAN can be reached;
   MAC address : unless you have a special reason to change this, just leave as is;
   Connection mode : for this example we use TCP-Client. The board will request a connection to the DabMux program;
   Remote IP : the IP address of the Raspberry Pi on which you operate the DabMux program. This can be on the same LAN or on another address, even over the Internet;
   Remote port : the port number that you have selected in the mux configuration file for the ZeroMQ handshake.

For this project we enable the ZeroMQ Client Handshake and select no delayed TCP ACK.

The next part of the interface page determines the output of the RF frontend.

The first setting is the amplitude, that can be set in 256 steps. For the best output do not put this too high, as we should ensure the signal is clean and as close as possible within the limits of the spectrum mask in the DAB specification. Next you can set the frequency. Do this according to the list of DAB channels. The next three settings will be discussed as a later moment. For now, we leave these as is. And finally in this part the status of the output is shown: active or not.

In the processing part most settings are to enable Single Frequency Network mode when 2 or more transmitter need to be synchronized to a GPS clock. The only setting we need to care about for now is the setting whether or not the board is equipped with additional buffer RAM. If it is, do enable these so more buffer capacity is available. The processing part also has some information on the state of the buffer and some flags about the processing.

The user name and password to access the webinterface can be set in the Authentication part. If you want to access the board over the Internet you better select something else than 'admin' and 'admin'.

Once you have set everything to your liking, click on 'apply config', which will load these settings. But in order to activate them you will need to restart the board as well.

The restart will also change its IP address to the one you selected. Make sure the network address you selected for the Raspberry Pi can be reached from the EasyDab board, over a LAN connection or even through the Internet. If you have the ODR-DabMux and ODR-AudioEnc active on the Raspberry Pi the EasyDab should be able to reach it and after about 10 to 20 seconds start to transmit on the DAB channel you set. Your DAB ensemble is on air !

Now, if you want to add Program Associated Data, let's see how to use ODR-PadEnc.