# Description on the Global Configuration File

As LoRadar is a variation of an offline gateway, it does not forward any packets to a network provider. Hence, configuration fields related to the server do not impact its operation. The main configuration should be the selection of channels that LoRadar should listen to. This is explained below, with `global_conf_915.json` including in-line comments on the configuration fields.

## Specifing channels
Eight channels can be configured to receive LoRa packets using 125 kHz bandwith. These channels are configured in the **chan_multiSF_x** settings. Each channel has an enable boolean, a selected radio and an intermediate frequency. The channel frequency will freq setting of the radio plus the 'if' setting of the channel.
* `enable:` true if this channel is enabled for use
* `radio:` selected radio to listen for packets
* `if:` intermediate frequency offset applied to the selected radio “freq” setting

Two additional channels can be configured with the chan_Lora_std and chan_FSK settings
* `enable:` true if this channel is enabled for use
* `radio:` selected radio to listen for packets
* `if:` intermediate frequency offset applied to the selected radio “freq” setting
* `bandwidth:` channel bandwidth
* `spread_factor (LoRa):` channel spreading factor (7-12)
* `datarate (FSK):` channel datarate in bps

## Other configurations
* `gateway_ID:` gateway identifier sent in each message to the network server
* `server_address:` address of the network server
* `serv_port_up:` port for sending uplink packets to the network server
* `serv_port_down:` port to ping network server and receive downlink packets
* `keepalive_interval:` interval to ping the network server
* `stat_interval:` interval to send stat messages to the network server
* `push_timeout_ms:` socket timeout when publishing messages to the network server
* `autoquit_threshold:` number of keepalive messages without response to wait before quitting Multi-Tech Systems, Inc.
* `forward_crc_valid:` enable to forward valid packets to the network server, default: true
* `forward_crc_error:` enable to forward CRC failed packets to the network server, default: true. The network server will reject packets with failed CRC, it may not be necessary to forward the packets except for a statistic of local RF quality or to monitor the gateway performance over time. Some random CRC failed packets are expected to be received from random noise.
* `forward_crc_disabled:` enable to forward packets without CRC enabled to the network server, default: false. LoRaWAN protocol expects uplink packets to have CRC enabled.
