You probably need to be a bit more clear. Do you mean the Linksysrouter is not showing up in Network devices in WIndows file explorer?
There may be possible of wireless SSID channels &or channel width conflict in your location.
If there are 2 SSID on the same channels /width, either one of them may be available or missing.
Login to the router settings to make the necessary changes to the SSID channels /width.
And do monitor for a period of time.
To find out if there are conflict on the SSID channels /width.
Do download phone Apps, such as Home WiFi Alert, analiti, WiFi Overview 360 & other Apps.
Run the scan on wifi channels and would show all available SSID channels for any conflict.
There should not have any SSID on the same channels /width.
i am not starhub staff.
I meant that 2.4 ghz link sometimes does not appear in the SSID list.
Thank you for your advice but I cannot find any of apps you suggested in AppStore.
Apprecite if you can let me know any similar app for iPhone.
As i am not familiar with iOS, but there are other apps available on both paid and free.
Such as Network Analyzer Lite, WiFi Analyzer Master Lite, and many other related free apps.
These are some of the free apps available that can do the job to detect for conflict, that is 2 or more SSID with the same channel.
For conflict of SSID channels, switch to the best available channels as indicated in the apps that would provide a guide, if any.
And the needs to monitor for the best channels for your location, as means of trial and error.
Once the connection speed is good & stable, then the test is complete.