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- YAGIMAX 1.02 3/90
-
- The YAGIMAX program represents my latest attempt at antenna modeling
- software. The algorithm used for YAGIMAX is not derived from MININEC
- as was the case with all versions of YAGINEC, but is based upon the
- asumption that Yagi antennas have a sinusodial current distribution
- which is well behaved. This requires that the user use realistic
- dimensions when using YAGIMAX for correct results.
-
- In order to accomodate more than the 10 element limit of YAGINEC,
- YAGIMAX has no help screens, or pattern plotting. Most of the
- information contained in the YAGINEC help screens is applicable
- to YAGIMAX. Patterns plots must be done on YAGINEC, however. Design
- files are transportable between YAGINEC, YAGIMAX, and TAPER.
-
- If you are a previous user of YAGINEC, the first thing you will
- observe is that YAGIMAX is exceedingly fast compared to YAGINEC.
- This is due to the fact that the elements are not segmentized and
- massaged through matrix inversion techniques (which is the real time
- consumer in YAGINEC/MININEC), but derived from the sinusodial current
- assumption mentioned above.
-
- You will notice that most of the entries become cued after first
- usage. Any cued prompt is entered by hitting <RET>. This is done
- because I am basically lazy when making repetitive entries. It has
- been assumed that this program is to be used for ham radio antennas,
- thus the cueing is relative to typical ham bands. Any entry can
- be overstruck, however.
-
- The maximizing feature is not perfect, but can be used on an element
- by element basic to maximize either forward gain, or front to back.
- Each element change is cycled through the algorithm three times to
- provide a glimpse of what the VSWR is doing at preselected low and
- high frequencies. Each change is displayed on the screen for the user
- to observe. In many cases the user may want to check the list and
- manually re-enter a chosen dimension rather than accept the maximizing
- output.
-
- Although it is included as a choice for maximizing, the driven element's
- length should never be used for optimization as it really has very little
- effect upon a Yagis performance except for feedpoint impedance. Also
- 2 element Yagis can display some rather unusual (and unusable) results
- when optimizing for forward gain using spacing adjustments. The
- feedpoint impedance can proceed to values close to one ohm!
-
- The results of YAGIMAX appear to be within one percent of those
- obtained with YAGINEC when using ten segments or more for calculation.
- The speed of YAGIMAX is about 50 times faster than YAGINEC using
- 8 segments per element. As with YAGINEC the more elements in the
- antenna, the slower the calculations.
-
- YAGIMAX will run in systems without a math co-processor but as with
- any math intensive program, much slower. A 20 element Yagi requires
- about 90 seconds per frequency step using an 8 mHz machine with no
- co-processor. The same antenna on my new 20 mHz 80386 machine with
- 80387 co-processor performs 20 steps in 40 seconds. For comparison
- YAGINEC on an 8 mHz machine without a co-processor takes almost one
- hour per frequency step for a 10 element Yagi!
-
- YAGIMAX 1.02 is the first general release of this program. As with
- all my programming efforts, YAGIMAX is placed in public domain and
- is not to be sold or used for commercial gain. While every effort has
- been made to reduce bugs or other problems, I will not be responsible
- for any problems encountered from using YAGIMAX.
-
- Should you wish to change the color selection in YAGIMAX, use YNINST.EXE
- as is done with YAGINEC. The file YN.SCR is the color combination
- selection. YAGIMAX requires its presence in the same directory to operate.
-
- YAGIMAX was written and compiled using Microsoft (R) QuickBASIC 4.5 (C)
- and does not require the presence of BRUN45.EXE to operate as it
- is a stand-alone version.
-
- If you enjoy this program don't hesitate to send your donations to the
- following address:
-
- Lew Gordon, K4VX
- P.O. Box 105
- Hannibal, MO 63401
- (314) 221-7730
-
- And no, I haven't built the 20 element 20M design contained on this disk!
- (yet!)