First 80M Contact--and I don't have an 80M antenna

My antenna is a G5RVjr--supposedly good on 10-40meters.  I use it on 20 and 40--I have had no success on other bands.

This week I'm chasing the Route 66 stations (see here), and I'm down to the last 3 out of 21.  Last night I was watching the spots for those 3.  One I couldn't hear, one couldn't hear me, and the other was on 80.  Just for grins, I went to see if I could hear it. I couldn't, but I did hear several other stations very clearly.  So, today I decided to see if I could transmit.  During the day I heard nothing.  Tonight there were no spots for Route 66 stations, but the New Jersey QSO Party was going on.  The first one I tried could not hear me, but another gave me a 59 signal report. First 80 meter QSO!

I have heard that it is possible to tune a 40m antenna for 80m but this is the first time I tried it.