Updated 2017-01-01 23:47:37 by gold

Twin Lead Folded Dipole Antenna and example demo eTCL calculator, numerical analysis  edit

This page is under development. Comments are welcome, but please load any comments in the comments section at the bottom of the page. Please include your wiki MONIKER in your comment with the same courtesy that I will give you. Its very hard to reply intelligibly without some background of the correspondent. Thanks,gold

gold Here is some eTCL starter code for a twin lead folded dipole antenna. The impetus for these calculations was checking calculations for a dipole antenna. Most of the testcases involve assumptions and rules of thumb.

The procedure starts with finding the radio wavelength in meters, wavelength = (velocity_factor*speed_of_light)/(megahertz* 1E6). The antenna length is set for half wavelength and is multipled by a correction factor for end distortion. The antenna height above ground is 2 wavelengths above ground.

# following statements can be pasted into eTCL console
 set project 1.0
 set wavelength [/ [* .95 300E6] [*  98.E6] ]   # 2.908 meters
 set wavelength [/ [* .95 300E6] [*  57.E6] ]   # 5.0 meters
 set wavelength [/ [* .95 300E6] [*  100.E6]]   # 2.85 meters

Testcases Section

In planning any software, it is advisable to gather a number of testcases to check the results of the program. The math for the testcases can be checked by pasting statements in the TCL console. Aside from the TCL calculator display, when one presses the report button on the calculator, one will have console show access to the capacity functions (subroutines).

Testcase 1

table 1printed in tcl wiki format
quantity value comment, if any
testcase number:1
98.1 :center frequency megahertz
1.0 :optional
1.0 :optional
2.90519877675841 :wavelength meters
1.452599388379205 :half wavelength meters
1.467125382262997 :corrected .5L antenna length meters or 57.18895412844037 inches
.5 :antenna lead meters
5.81039755351682 :height above ground meters

Testcase 2

testcase number:2
100.1 :center frequency megahertz
1.0 :optional
1.0 :optional
2.8471528471528473 :wavelength meters
1.4235764235764237 :half wavelength meters
1.437812187812188 :corrected .5L antenna length meters or 56.046317682317685 inches
.5 :antenna lead meters
5.694305694305695 :height above ground meters

Testcase 3

table 3printed in tcl wiki format
quantity value comment, if any
testcase number:3
57.1 :center frequency megahertz
1.0 :optional
1.0 :optional
4.991243432574431 :wavelength meters
2.4956217162872156 :half wavelength meters
2.5205779334500877 :corrected .5L antenna length meters or 98.25282661996499 inches
.5 :antenna lead meters
9.982486865148863 :height above ground meters


Screenshots Section

figure 1.

figure 2.

figure 3.

figure 4.

figure 5.

figure 6.

figure 7. Alternate Salvage Antenna stripped

figure 8. Alternate Salvage Antenna tinned

figure 9. Alternate Salvage Antenna Mounted on Scrap Board


References:

  • goggle "twin lead dipole"
  • Wikipedia on dipole
  • Antennas, see snowflake antenna, tikalon blog,
  • May 16, 2016, Dev Gualtieri, excellent article

Appendix Code edit

appendix TCL programs and scripts

        # pretty print from autoindent and ased editor
        # Twin Lead Dipole Antenna calculator
        # written on Windows XP on eTCL
        # working under TCL version 8.5.6 and eTCL 1.0.1
        # gold on TCL WIKI, 15dec2016
        package require Tk
        namespace path {::tcl::mathop ::tcl::mathfunc}
        frame .frame -relief flat -bg aquamarine4
        pack .frame -side top -fill y -anchor center
        set names {{} {center frequency megahertz :} }
        lappend names {optional, :}
        lappend names {optional, :}
        lappend names {answers: whole wavelength meters :}
        lappend names {half wavelength  meters :}
        lappend names {corrected .5L antenna length  meters: }
        lappend names {lead meters: }
        lappend names {height above ground meters:} 
        foreach i {1 2 3 4 5 6 7 8} {
            label .frame.label$i -text [lindex $names $i] -anchor e
            entry .frame.entry$i -width 35 -textvariable side$i
            grid .frame.label$i .frame.entry$i -sticky ew -pady 2 -padx 1 }
        proc about {} {
            set msg "Calculator for Twin Lead Folded Dipole Antenna 
            from TCL WIKI,
            written on eTCL "
            tk_messageBox -title "About" -message $msg } 
       proc pi {} {expr acos(-1)}       
       proc calculate {     } {
            global answer2
            global side1 side2 side3 side4 side5
            global side6 side7 side8
            global testcase_number
            incr testcase_number 
            set side1 [* $side1 1. ]
            set side2 [* $side2 1. ]
            set side3 [* $side3 1. ]
            set side4 [* $side4 1. ]
            set side5 [* $side5 1. ]
            set side6 [* $side6 1. ]
            set side7 [* $side7 1. ]
            set side8 [* $side8 1. ]
            set megahertz $side1  
            set conv_factor $side5 
            set speedoflight 300E6
            #set velocityfactor .87 ; alternate velocity factor
            set velocityfactor .95
            set wavelength [/ [* $velocityfactor $speedoflight] [* $megahertz 1E6 ] ]
            set halfwavelength [* $wavelength .5 ]
            set antennacorrection [* $halfwavelength 1.01 ]
            set antennalead .5
            set heightaboveground [* 2. $wavelength ]
            set side4 $wavelength
            set side5 $halfwavelength
            set side6 $antennacorrection 
            set side7 $antennalead
            set side8 $heightaboveground
                    }
        proc fillup {aa bb cc dd ee ff gg hh} {
            .frame.entry1 insert 0 "$aa"
            .frame.entry2 insert 0 "$bb"
            .frame.entry3 insert 0 "$cc"
            .frame.entry4 insert 0 "$dd"
            .frame.entry5 insert 0 "$ee"
            .frame.entry6 insert 0 "$ff" 
            .frame.entry7 insert 0 "$gg"
            .frame.entry8 insert 0 "$hh" 
             }
        proc clearx {} {
            foreach i {1 2 3 4 5 6 7 8 } {
                .frame.entry$i delete 0 end } }
        proc reportx {} {
            global side1 side2 side3 side4 side5
            global side6 side7 side8 
            global testcase_number
            console show;
            puts "%|table $testcase_number|printed in| tcl wiki format|% "
            puts "&| quantity| value| comment, if any|& "
            puts "&| testcase number:|$testcase_number | |&"
            puts "&| $side1 :|center frequency megahertz |   |&"
            puts "&| $side2 :|optional| |& "
            puts "&| $side3 :|optional| |& "
            puts "&| $side4 :|wavelength meters| |&"
            puts "&| $side5 :|half wavelength meters  | |&"
            puts "&| $side6 :|corrected .5L antenna length meters or [expr $side5*39.37008] inches  |  |&"
            puts "&| $side7 :|antenna lead meters |  |&"
            puts "&| $side8 :|height above ground meters|  |&"
            }
        frame .buttons -bg aquamarine4
        ::ttk::button .calculator -text "Solve" -command { calculate   }
        ::ttk::button .test2 -text "Testcase1" -command {clearx;fillup 98.1 1. 1.0 2.908  1.45 1.46 .5 5.8}
        ::ttk::button .test3 -text "Testcase2" -command {clearx;fillup 100.10 1. 1.0 2.85  1.425  1.439 0.5 5.7 }
        ::ttk::button .test4 -text "Testcase3" -command {clearx;fillup 57.10 1. 1.0 5.0  2.5  2.525 0.50 10.10 }

        ::ttk::button .clearallx -text clear -command {clearx }
        ::ttk::button .about -text about -command about
        ::ttk::button .cons -text report -command { reportx }
        ::ttk::button .exit -text exit -command {exit}
        pack .calculator  -in .buttons -side top -padx 10 -pady 5
        pack  .clearallx .cons .about .exit .test4 .test3 .test2   -side bottom -in .buttons
        grid .frame .buttons -sticky ns -pady {0 10}
               . configure -background aquamarine4 -highlightcolor brown -relief raised -border 30
        wm title . "Twin Lead Folded Dipole Antenna Calculator"      

Pushbutton Operation

For the push buttons, the recommended procedure is push testcase and fill frame, change first three entries etc, push solve, and then push report. Report allows copy and paste from console.

For testcases in a computer session, the eTCL calculator increments a new testcase number internally, eg. TC(1), TC(2) , TC(3) , TC(N). The testcase number is internal to the calculator and will not be printed until the report button is pushed for the current result numbers. The current result numbers will be cleared on the next solve button. The command { calculate; reportx } or { calculate ; reportx; clearx } can be added or changed to report automatically. Another wrinkle would be to print out the current text, delimiters, and numbers in a TCL wiki style table as
  puts " %| testcase $testcase_number | value| units |comment |%"
  puts " &| volume| $volume| cubic meters |based on length $side1 and width $side2   |&"  

gold This page is copyrighted under the TCL/TK license terms, this license.

Comments Section edit

Please place any comments here, Thanks.