I can't work the aerial, and no one's listening

I stuck the 20m whip up on the car; had a lot of trouble tuning it to a decent SWR.  I ended up getting my old ATU and putting it in line - surely I should be able to tune the aerial without one since it is a one band aerial?  I managed to get the SWR "quite low" in the end and drove down to One Tree Hill on the border of Basildon and Thurrock.  (This was about 1700 local time).

 

This is the first time I've tuned into any amateur band since 2006.  Since then we're well and truly in the sunspot minimum so I wasn't expecting to hear a great deal.  I was surprised to hear the band being very difficult from last time - there weren't a lot of stations around but they were a lot further away than I expected.  Some of the stations I heard were:

 

A41MO (Muscat, Oman)

BT1OB (Beijing, special event station for Olympics)

E21EIC (Bangkok, Thailand)

EC8AUZ (Gran Canaria, Canary Islands)

HS0ZEE (Chian Mai, Thailand)

JA1 (didn't catch the full call, he was in Tokyo talking to the ZB2 station)

LA1CI (Norway, about 70 deg N)

TC17GS (Istanbul, special event station to celebrate Galatasary's 17th Turkish league title)

VU2DK (Poona, India)

ZB2FX (Gibraltar, by far the strongest signal on the band)

9H5DX (Malta)

 

The bad news is that they were usually working pile-ups, and none of them heard me.

 

I did call out to a SO station (special call from Poland), and I THINK he heard me as he repeated the golf alpha from my callsign, but then came back to say he was only working C-contest (whatever that was) and didn't come back a second time.

 

So still not sure if there's a problem with the audio on my radio, or the transmission in general, but the aerial's obviously picking something up.