I've been contemplating an 80m 4 square for a couple of years. Been playing
with all the modelling programs. It appears that the high angle lobe off the
back can be reduced by either changing the driving phase to -110, -220 or
thereabouts or by increasing the element spacing. Rather than 1/4 wave between
elements, 1/2 wave across the diagonal looks good with the standard -90, -180
phasing. The increased spacing makes it look attractive for 160 meters also.
The problem is deciding on an efficient dual band element. Base loading would
be the easiest but least efficient. Top loading is better but requires some
sort of switch. A trap reduces bandwidth too much. I was wondering about a
vacuum relay but not sure of what voltage to expect. Assuming a 65 ft 3 in
dia element with 1kw input any educated guesses? Any alternative ideas?
Advice and opinions needed!
73, Roger
--
FAQ on WWW: http://www.contesting.com/FAQ/topband
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|