What Use Is An F-call?

What use is an F-call? Troubleshooting is a skill that has to be learnt. Part of getting my Foundation License included a module on the skill. I've been working with complicated equipment for decades and to me, an amateur radio kit really isn't that complex. As you might know, I've got a portable kit. I've set it up at least 50 or so times in the last year. I know this system backwards, still every now and then something unexpected happens. Twice now, my own gear has surprised me. A couple of weeks ago I went on air to join a regular net. I tuned to the appropriate frequency and made my call, but I couldn't hear anyone. I called again, still nothing. I looked at the frequency, all as expected. The voltage was fine, I could see my SWR meter working as expected, when I keyed the mike, all was normal. I looked at the clock to make sure that I wasn't on the wrong time-zone. I turned up the volume, still nothing. I tuned to another frequency, nothing. In fact, apart from the fact that I knew the volume was up,