A Email conversation with Robert Blum got me to review the W8JI web
page today.
He has many articles that are very useful and chop full of needed
information and
most SWLs will benefit from a careful review of his web page.

Among the most relevant to my main concern is his receiving_basics;
http:/www.w8ji.com/receiving_basics.htm., he addresses noise and
covers the "typical" urban, suburban and rural operating areas. And
why
noise considerations out weigh gain.

Another excellent web page that every SWL should study is L. B.
Cebik's (W4RNL)
well thought out pages at http://www.cebik.com.

These guys are world class hams and while their primary focus is ham
radio, they
are well aware of the old saying "If you can't hear them, you can't
work them".

They clearly understand the need for superior receiving antennas.

Terry