[HCARC] Reflectors For A Vertical Antenna

[Kerry Sandstrom]

Gary,

The answer is yes and no.  To be really effective, the reflector .15 to .25 
wavelengths from the driven element.  If it is a 3-element parasitic (Yagi) 
array, the driven element should be about .175 wavelengths.  It is possible 
to use closer spacing but the antenna becomes difficult to match and it will 
be very narrow band.  The problem with using guys for the parasitic 
(director/reflector) elements is the guys are unlikely to be parallel to the 
driven element and will probably be too close.  If you really wanted to do 
this, I see two choices: One is to have a horizontal insulated spacer at the 
top of the vertical to increase the spacing of the guys and bring them 
straight down  and the second is to have the guys attach to an insulated 
mast that is much higher than the vertical so by the time they are at the 
level of the vertical, they will be away from it and nearky parallel.  i 
don't thinkeither one is practical.

People have built arrays of parasitic vertical elements and they do operate 
as a Yagi.  Most people, however, will use 2 or more verticals all driven. 
By changing the relative phase of the drive to the individual verticals you 
can change the radiation pattern to favor different directions.  The Antenna 
Handbook  as well as the ARRL Handbook and various EE antenna books all 
discuss arrays of driven vertical aelements.

Kerry