How to log wifi speed and strength? My wifi drops out multiple times per hour. It says it is connected but it goes to 1kb/s up and down and nothing works until I turn wifi off, then back on. Then it will work until it doesn't.

I want to log the speed and strength so I can diagnos and maybe use to convince my ISP that they have an issue (they provide the connection and the wireless router).

What app can log the speed and strength of a wifi connection? I googled but only found Windows bloatware type apps.
You can follow Apple's own steps on how to diagnose your WiFi connection. You can look specifically for the report section in that page, which explains how to and where to save the resulting data.

As a TL;DR, look in Spotlight for Wireless Diagnostics and click Window in the menu bar, there go to Logs.