What Use Is An F-call?

What use is an F-call? Today I was unable to run my weekly net from my QTH, so I planned to run my station portable. Last night I put my battery pack in the boot of my car, put the mag-mount on the roof, screwed in the antenna and folded it over so I wouldn't damage it when I drove out of the garage in the morning. I also put my radio, a Yaesu 857d on the passenger seat, ran the power cord from the boot to the front-seat, plugged the antenna lead in and added my log book. This morning I drove out of the garage, stuck my antenna up, plugged in the power and made a test transmission, only to see the SWR go through the roof. I wasn't sure what was going on, so I checked the antenna connector, all solid, checked the mag-mount on the roof, unscrewed the antenna and then screwed it back in again. Another test transmission, another high SWR and no repeater beep acknowledging my existence. I checked on the local aviation beacon but couldn't hear it. I went back into the garage, pulled out another mag-mount, plugg