Modifying the ASIAir Default Startup Settings

 V1.5.3

On occasion some users may need to change the default start up behavior on the ASIAIR or ASIAIR Pro. ZWO has made this possible through the modification of the "ASIAIR_Config.txt" file. The settings are the same across all ASIAIR platforms and versions.

Before attempting to do this there are some things to know. First and foremost, before attempting any manual modification of the config file you should ensure you have made a successful backup image of the card as well as copied off the "zwoair_license" file to a safe place. DO NOT SKIP MAKING A BACKUP FIRST.

The ASIAIR Backup and Restore procedures are located in the ASIAIR users manual located here:

https://astronomy-imaging-camera.com/manuals-guides

Lastly to perform this operation you need to insert the SD card into your PC in order to edit the configuration file. Because ASIAIR uses a linux based operating system all but one of the file systems on the card will show as corrupted or say they need formatting. DO NOT FORMAT ANY OF THESE PARTITIONS. Just click cancel through all of these, there should be only 3 or 4 pop ups to cancel.

Now that you have a backup and have avoided formatting the card, we can begin. On the Boot filesystem, normally assigned to E: but could be something else if E: was already assigned by your operating system, there will be a file called "ASIAIR_Config.txt". You should edit this with only "Notepad". The file contains the following entries:

#ASIAIR boot config file

#ASIAIR boot as 2.4GHZ WiFi if set to 1

AP_boot_24G=0

#ASIAIR 5G channel,36 or 149

AP_5G_channel=36

#ASIAIR 2.4G channel, range: 1-11

AP_24G_channel=11

#AP SSID and password will be reset to default value if set to 1

AP_reset=0

Here is an explanation of each option and when you may find it necessary to change the option. Most people will never need to edit this file.

AP_boot_24G

This option controls what wifi speed is enabled when the device boots up. This is sometimes needed for older phones or tablets that do not support 5ghz wifi. Without changing this setting you would not be able to connect to the ASIAIR. Currently this option is really only useful if you have an Original ASIAIR. The Pro version starts up out of the box in 2.4ghz mode so should not need to be changed. This option however makes it possible to force this setting in the event it is changed to 5ghz accidentally or you always want the device to start up in 2.4ghz.

To force start up in 2.4ghz wifi change this option from 0 to 1.

AP_5G_channel

This option controls what channel the ASIAR uses when running in 5Ghz AP mode. The default is to use channel 36 which uses a lower frequency and therefore penetrates walls a bit better. The other option is to use channel 149. This provides a slightly higher data rate at the expense of needing a clear line of sight between the ASIAR and your phone or tablet.  It is important to note that the 802.11ac specification dictates that the higher frequencies use a higher output power to compensate for the extra weakening of going through walls and some types of coated glass.  If you have a direct line of site to your scope or use extenders you could benefit from using channel 149 instead.  Another possible need for this is if you have multiple 5Ghz wifi in your vicinity.  Changing this will allow them to better coexist in close proximity.

To change 5ghz wifi usage to channel 149 change this option from 36 to 149

AP_24G_channel

This option controls what channel ASIAIR uses when running in 2.4Ghz AP mode. The default is to use channel 11. If there are other 2.4Ghz Access Points in the area using this channel you may need to change this to something else in the range of 1 to 11 to avoid a conflict and connection failures.

To change 2.4ghz channel usage change this option from 11 to anything in the range from 1-11

AP_reset

This option is used to reset the SSID and the Wifi settings back to factory defaults in the event it has been changed and the device is no longer accessible.

To reset the wifi SSID and password back to factory default change this setting from 0 to 1

Once you have made any desired changes, save the file and exit notepad. It is important to make sure the SD card is properly and safely ejected before removing it from the computer. You can do this by right clicking the USB stick icon on your task bar and click "Eject SDHC Card". When prompted that it is safe to remove you can do so.

Carefully replace the SD card back into the ASIAR and the device will now boot with the desired settings. If the new settings enhance your experience, I would recommend making another backup image of the card to save time later if/when the need arises to reimage it.