Pocket VNAs are quite nifty - you can get some now that use your phone as the display.
[my most-recent antenna tweaking involved multiple trips up and down ladders/scaffolding in the rain. Not fun when it's a 3-band antenna and the adjustments for the various bands all interact!]
More options:
http://www.aa5tb.com/efha.html - my portable version is based on his Fig.15, with the 'cold' end of the tuned circuit connected to the coax braid and also to a short earth-lead with an alligator-clip which I attach to the same barbed-wire fence whose fencepost provided the anchor-point.