Topband: 160m / portable

[christian schneider]

Hello,
having no antenna at home I operate only /portable - now trying 160m.  After reading some of of the regular web and paper ressources I have some questions:

- How does the terrain influence the radiation pattern of verticals? Are slopes from a 
hilltop improving the lower lobes in the way TA-software shows it for horizontal 
antennas? In one post however I read about a negative influence of slopes on verticals. 

- What factors and ingredients of soil shape the ground conductivity in the far field? I 
understood that it is not measurable. But is there anything more than "rich soil, typ 
Dallas" available? It may help in choosing between different QTHs. Does "rich" mean 
fertile?

- Length of BOGs is recommended between 57 and 160m - what are the experiences?

Of course I´m happy with any other tips and experiences about /p-operating on 160m. As a 
humble start I work with an oldfashioned singlewire-fed windom (81m) from a hilltop. 
Without real trees the vertical section (with planned 16 radials each 20m) and 
average heigth of the wire are only 8-10m. Still looking for a freestanding and accessible 
15m+ tree with enough place for Inv-L, BOGs and radials.

Thanks in advance,
Chris (DL8MBS)