Disclaimer and Apology
This is a shameless rip-off of George Murphy's (VE3ERP) fabulous HamCalc v. 9.4. Get the original if you want to see some nifty DOS-Basic programming. Lacking a full-time DOS machine, I've been forced to convert a tiny fraction of his massive collection. I originally built Excel spread-sheets, but they lack the polish of an application program. I found that Java worked much better, and also permits web publishing.
The original works wonderfully in Metric or American units. I haven't attempted to make this program capable of arbitrary units on display. This is strictly in American units.
There are two major, known compatibility issues.
Problems, questions, complaints, etc. to S_Lott@yahoo.com
Fine Print: This software has no warranty of fitness for any purpose whatsoever. If it doesn't seem to "work", I may be sorry, but I am not liable in any form. I will do my best to make such repairs as I see fit.
This is built with a Java applet based on my own Model class. A Model represents a mathematical model and includes fields which represent variables of that model. A Model can compute any one field given values in one or more other fields. Each field is dependent on zero or more other fields. A field which depends on zero other fields must be entered can cannot be computed. Other fields will be computed as data is entered.
As an example, consider the RTD model: rate*time = distance. We can solve for either of the other two: r=d/t and t=d/r. The model knows all three formulae and picks one based on the order of the user's of inputs.
As a usability note, Java does not recognize TAB as a significant GUI action. It's just another character. Return or Enter are GUI actions. I could (and perhaps will) change this in the future. For now, you must click on the field, enter the data, and either hit return or click on another field to see the calculation. Also, your JVM may not handle color changes correctly.
As you enter values for fields, the model checks all other fields to see if they can be computed from the fields available. Fields you enter are marked in <FONT COLOR="#0000FF">blue</FONT>, fields it computes for you are marked in <FONT COLOR="#FF00FF">magenta</FONT>.
Generally, the model uses a least-recently-used algorithm to determine what is computable. If you enter rate and time, it computes distance. If you change either rate or time, it recomputes distance. If you change distance, it recomputes whatever you entered earliest.
For example, enter rate, enter time, get distance; change distance. Since rate is least recent, it will be computed from time and distance. The colors will change to reflect this.
Some web pages have multiple models. When there are two (or more) models in the same panel, fields with identical names will be copied down the panel from a model to the model below. You can change these in subsequent models, but the change will not ripple back up the panel to prior models.
Some models are fairly complex, and have several variables with complex relationships. An example is the air coil design. A typical scenario for coil design proceeds as follows.
Note this common problem: If you do not change the coil diameter, the recomputation of iductance will not be completed. Manual entry of both coil diameter and number of turns (as well as TPI) is required to compute inductance. The computed (in <FONT COLOR="#FF00FF">magenta</FONT>) value is not sufficient, you must enter a value to make the field turn <FONT COLOR="#0000FF">blue</FONT>.
List of all HamCalc Modules
This is the complete list of HamCalc v 9.4 modules.
© 2005, 2009 Steven F. Lott
Made: 2009-05-20 17:28:00.065251
Webmaster: s_lott at yahoo.com