I think that this is a valid topband topic. I would like to find or gather
information on which directional pattern might give the best s/n results. For
example when you look at EWE patterns in the WA2WVL Feb 1995 QST article the
estimates for f/b and for BW are about as follows:
single element 30 db f/b, 150 degree BW
broadside elements, 150' spacing, 20 db f/b, 45 degree BW
endfire elements 30 db f/b, 90 degree BW
With the two element arrays there is some tradeoff between f/b and BW. My
limited computer models show somewhat better f/b for the endfire and somewhat
greater BW for the broadside than the above numbers.
Whatever the numbers are, do you reduce noise more with better f/b or with a
narrower BW?
Like most topband topics I'm sure there may not be an easy answer - noise is
not that simple. Also another factor is reduction of signal hash from nearby
strong stations/signals. One advantage of the broadside array is that there
is no critical phasing involved.
73 Bob W7LR Montana w7lr@aol.com
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|