# Mathematica help needed, please (very simple?)

I need to construct a direction field plot for a differential equation and I have this code

Needs["GraphicsPlotField"];
PlotDirectionField[ff_, {x_, a_, b_}, {y_, c_, d_}] := Module[{f}, f = \
Compile[{x, y}, ff]; PlotVectorField[{190, f[x, y]}, {x, a, b}, {y, c,
d}, ScaleFunction -> (1 &), Axes -> True, Ticks -> None, Frame -> True,
AspectRatio -> 1] ];

and after that I plot the field entering the following code
PlotDirectionField[f[x,y], {x,a,b}, {y,c,d}]
where f[x,y] is the right hand side of my equation.

My problem is that I need to show field for x in quite big interval (from 0 to 30 - a=0,b=30) and I know that the solution curve behaves differently between 0 and 1 than what the field shows. How can I make the plot so that on the x axis I have intervals of, let's say, 0.1 instead of 1 all the way between 0 and 30?

Thanks for help!