[Elecraft] DL1 Pout & SWR function for Palm based RPN Calculator

[Rod N0RC]

Folks,

For a number of years I've used "RPN", a programmable, postfix
scientific
calculator for the PalmOS. Details at:

http://www.nthlab.com/software/rpn/welcome.html

RPN is cheap, $18, and free to try. It's programmability makes it very
useful for radio/electronics calculations in the shack/workbench.

If you choose to give RPN a try, here are two functions I created; the
first to calculate Power output from the Elecraft DL1 voltage reading;
The second to calculate SWR from a forward/reflected power measurement.
Cut and paste them into RPN per instructions offered with the product
and enjoy

RPN.2\DL1 Power Meas.\
"DL1 Pwr Calc"
"V(dl1)->P"#'1.414' * #'0.15' + g1 * #'50' /;
\DL1 measured voltage in X stack location

RPN.2\SWR Calc\
"SWR";
"Swr Y=Pr X=Pf"/ s g1 1 + r2 1 r2 - /;
\Pr = reflected power in Y stack location
\Pf = forward power in X stack location

73, Rod N0RC


For the curious here is an annotated version for the source above:

  \\ Required RPN header with optional comment
RPN.2\DL1 Power Meas.\

  \\ Name that appears in RPNs function selector drop down list
"DL1 Pwr Calc"

  \\ button text "V(dl1)->P" that appears on screen
  \\ to execute the calculation given in DL1 instructions
  \\ #'1.414' * multiplies topOfStack "X" by 1.414
  \\ #'0.15" + adds 0.15 to result
  \\ g1 dups X to Y stack location
  \\ * multiplies X * Y, e.g. V^2
  \\ #'50' / divides result by 50, result Pout
"V(dl1)->P"#'1.414' * #'0.15' + g1 * #'50' /;

  \\ another comment
\DL1 measured voltage in X stack location

---


  \\ Required RPN header with optional comment
RPN.2\SWR Calc\

  \\ Name that appears in RPN's function selector drop down list
"SWR";

  \\ button label and calculation
  \\
  \\ computes square root "s" of (Pr/Pf)
  \\ dups it on the stack "g1"
  \\ add 1 "1 +" to X
  \\ rotates "r2" X Y on stack computes 1 - square root "s" of (Pr/Pf)
  \\ divides Y by X stack
  \\ equation from ARRL handbook
"Swr Y=Pr X=Pf"/ s g1 1 + r2 1 r2 - /;

  \\ comments
\Pr = reflected power in Y stack location
\Pf = forward power in X stack location
\ computes ( 1 + sqrt(Pr/Pf) ) / ( 1 - sqrt(Pr/Pf) )

                        * * *