NEC2 model of 40m loaded cubical quad
On Dec 14, 10:03�pm, Scott M wrote:
Gary,
I wrote some code to automate the optimization of the quad for my
goals - but my code only deals with element length, so I am hoping
that I don't need to add more code to manipulate the value of the load
too.
-Scott, WU2X
- Show quoted text -
OK, for modelling purposes, you can keep the load constant, and vary
the element lengths. From a practical standpoint, if you have this
beast up in the air, tuning is easier with a tapped inductor.
Other factors that will effect the gain and F/B are the element
spacing, and how high you can get the thing. Practically, these are
not things you can change easily.
I just did a quick 2 element 66% (reflector) quad in a diamond
configuration with 17' spacing on EZNEC, and got a 10.25 dbi gain at
35 degrees. F/B about 13 db. Feedpoint impedance was 44+j0 with a
678pf shunt capacitor. The element lengths were the same on both,
varied loads to get max gain and best match. The center of the
diamond was 50' up.
Gary N4AST
|