Wi-Fi Connection problems

I have problems connecting to the internet via Wi-Fi using my Apple Mac Mini running Mac OS Sierra version 10.12. It keeps dropping out, and can not connect to my home network despite this being shown as the only network in the drop dow menu. Run Diagnostics is worse than useless providing no answers.
I had blamed my router for being flakey, but it works ok on my Apple Mac iBook G4 running Mac OS 10.5.8. Indeed I am using this setup to write and hopefully post this pleas for help.

mactaffy said:

I have problems connecting to the internet via Wi-Fi using my Apple Mac Mini ...

Click to expand...

It sounds like the problem isn't due to a lack of signal strength. It may be due to conflicting signals. Usually you can easily fix this by changing your Wi-Fi channel number.

I've found these articles to be extremely helpful in dealing with Wi-Fi problems:

Five quick fixes for Wi-Fi troubles in OS X
http://www.macissues.com/2015/04/30/five-quick-fixes-for-wi-fi-troubles-in-os-x/

Fix or help stem Wi-Fi connectivity problems in OS X
http://www.macissues.com/2014/10/31/fix-or-help-stem-wi-fi-connectivity-problems-in-os-x/

How To Change Your Wi-Fi Channel Number
http://www.howtodothings.com/computers-internet/how-to-change-your-wi-fi-channel-number
Scroll down to: "Here's how to do it on a Mac:"

Download:

istumbler (free)
http://istumbler.net/

to tell you about signal strength. It really makes a difference how things are oriented. You may be able to solve your problem just by re-orienting things.

@Randy:

The latest version of iStumbler is no longer free. It's $25 for a license. I do have the free version but it's from several years ago when it was free or donate ware.