Mac Airport utility wifi scanner

You can do that right on your Mac, looking at what your Mac is seeing, not what the Router is seeing.

Hold down the option key and click on the Wi-Fi icon on the menubar. you get a display like this older one:

you also immediately see names of other networks visible from your Mac, and their strength in bars.

Wireless diagnostics opens up a whole other world. There are five displays avaialable, including one that looks like most "driver" programs:

Check for Wi-Fi issues using your Mac - Apple Support

However, DON'T create a "diagnostics report" unless someone at Apple has asked for it. It is merely a DUMP of every possible setting that could possibly influence your correction. It is so big, it is embarrassing, so they compress it. It is useless.

In the next-to-last paragraph, they list the important functions available on the menus inside Wireless Diagnostics:

• Info

• Logs

• Scan -- finds Wi-Fi routers in your environment and gathers key details about them.

• Performance

• Sniffer

• Monitor

these are really interesting, and since you are looking for something like these, I think you will find them helpful.

SCAN:

if you want that and also want to look at the spectrum, WiFi Explorer is cheap and has a three day free trial in the Mac App store:

drag and drop on Preview, then stretch and scroll the window for larger.