Q:

vertical 40m antenna takeoff angle

I built a 40m vertical using the W8AMZ design https://www.amateurradiosupplies.com/v/vspfiles/assets/images/40m_vertical_monopole_-_manual.pdf
Seems to be working for the most part.  But I'm not sure if it's really exhibiting a 22 degree takeoff angle.  I have it about 8 feet off the ground.
I get really strong signals from closer QTHs.. like +20 or +40 over S9.  I'm in western NY state and i get the strongest signals from NJ, WV, MI.  TX is pretty solid, but it really starts to fade around AZ and CA as well as NV.
It's hard to tell if it's just a propagation thing or a distance thing.  The fact that the closer stations are booming makes me think it's a combination of distance and high takeoff angle.
Do you think lowering or raising the antenna would change anything?  I have the radials as close to 180 degrees and level as possible.  How critical is that?
EDIT: as far as dealing with common mode current is concerned, I have 8 turns of the RG8X feedline going through one of these at both the feedpoint and shack entrance: http://palomar-engineers.com/ferrite-application-experts-2#!/FSB31-1-ID=1-RFI-Range-1-300-MHz/p/74532157/category=21480229
After that, the feedline goes througha T connector which is attached to a round rod.  The bottom part of the "T" has a PL-259 connector with a bleeder resistor across it: http://palomar-engineers.com/antenna-products/antenna-static-bleeders/Coax-Static-Bleeder-p74882773

A:

If you model this antenna, it does predict a 22° takeoff with the radials 8 feet off the ground. Doubling the height would change the take off to perhaps 21°.
You may wish to consider a good current mode balun at the feedpoint and another one prior to entering the shack in order to reduce common mode current which will alter the directional characteristics of the antenna. If you can bury the coax in a couple of feet of ground immediately below the antenna, this will also help reduce common mode currents. 
If you have an antenna analyzer, you may also wish to experiment with adding additional radials. While this will not have any significant effect on the takeoff angle, it may improve the efficiency of the antenna. Keep adding radials until the feedpoint impedance of the antenna no longer changes to any significant degree.

