From 5dbb60613ffdd746a3fbed37a1ec1defaa34e9ba Mon Sep 17 00:00:00 2001 From: miguel <31931809+miguelvaca@users.noreply.github.com> Date: Tue, 21 Mar 2023 22:38:23 +1100 Subject: [PATCH] Update short_antenna.html --- short_antenna.html | 110 ++++++++++++++------------------------------- 1 file changed, 34 insertions(+), 76 deletions(-) diff --git a/short_antenna.html b/short_antenna.html index f2ae5c5..9750252 100644 --- a/short_antenna.html +++ b/short_antenna.html @@ -7,7 +7,7 @@ -
Miguel VK3CPU - Loaded Dipole Antenna Calculator
+
VK3CPU - Loaded Dipole Antenna Calculator
@@ -23,8 +23,8 @@
- - + +
@@ -34,15 +34,14 @@

Notes:
- RF Inductor Calculator was developed to help users predict the RF characteristics of a single-layer solenoid-style air-core inductor.

+ This loaded dipole antenna calculator was developed to quickly estimate the inductance required for a coil-loaded dipole antenna, using + slider widgets.

Inputs via the slider widgets:
    -
  • ⌀a : Conductor diameter slider changes AWG from 0-40. Actual diameter displayed in decimal inches.
    • -
  • ⌀b : Coil diameter in decimal inches.
    • -
  • c/a : 'c' is the winding-to-winding distance, measured from the conductor mid-points. The 'a' is the conductor diameter, so 'c/a' is the spacing ratio. (c/a >= 1.1) - A low-value will increase the resistance due to the proximity effect.
    • -
  • N : Number of turns or windings.
    • -
  • f : The frequency of interest (MHz) for some of the calculations. Frequency dependent results are shown on the top-right.
    • +
  • f : The frequency of operation in MHz.
    • +
  • l : Length in percent compared to a half-wave dipole.
    • +
  • d : Distance of the coil/inductor from the feedpoint to the end, in percent.
    • +
  • AWG : Conductor diameter slider changes AWG from 0-40. Actual diameter displayed in decimal inches and millimeters.

Characteristics on the left are independent of frequency, while the characteristics on the right are dependent on the selected frequency.

Each of the graphic representations attempt to keep the relative geometry correct, without exceeding the drawing boundary. The coil diameter @@ -62,15 +61,6 @@

  • SRF : Self-resonant frequency (MHz) for the unloaded coil.
  • wire : Length of wire required to wind the inductor.
    • -
      Frequency dependent:[R] (Text goes RED when selected frequency > SRF. Inductor model is not accurate once SRF is exceeded.) -
    • f : Selected frequency in MHz
      • -
    • δ : Skin depth due to skin effect (μm)
      • -
    • Rac : AC resistance is calculated using the skin effect and proximity resistance from empirical data collected by Medhurst using the spacing ratio, and length-to-diameter ratio.
      • -
    • Xₗ : Inductive reactance at the given frequency. (Ω) - pure inductive component, ignoring parasitic capacitance
      • -
    • Z : Complex impedance at the given frequency. (Ω) - includes losses due to series Rac and parallel parasitic C
      • -
    • |Z| : Impedance magnitude at the given frequency. (Ω)
      • -
    • Q : Effective Quality Factor of the inductor at the given frequency. - (|Z.im|/Z.re)
      • -
    @@ -133,16 +123,7 @@ frequency_hz : 0.0, L : 0.0, - C : 0.0, - Rdc : 0.0, - SRF : 0.0, - Xl : 0.0, - Xc : 0.0, - Z : 0.0, - skin_depth : 0.0, - Rac : 0.0, - Q : 0.0 }; // Solve all the parameters, and re-draw the canvas: @@ -154,18 +135,21 @@ dipole.length_feet = dipole.length_meters * 3.28084; dipole.cond_diameter_meters = 0.001 * awgToMm(40.0 - conductor_diameter_slider.value); dipole.cond_diameter_inches = dipole.cond_diameter_meters * 39.37008; - dipole.spacing_ratio = 0.01 * inductor_distance.value; - dipole.distance_meters = inductor_distance.value * 0.005 * dipole.length_meters; + dipole.spacing_ratio = 0.01 * inductor_distance_slider.value; + dipole.distance_meters = inductor_distance_slider.value * 0.005 * dipole.length_meters; dipole.distance_feet = dipole.distance_meters * 3.28084; // Frequency independent characteristics: - dipole.L = 0.0; - // Redraw the canvas: - //drawDesign(); + dipole.Xl = getInductanceFromDimensions(dipole.frequency_hz * 1e-6, + dipole.length_feet, + dipole.distance_feet, + dipole.cond_diameter_inches); + dipole.L = dipole.Xl / (2 * Math.PI * dipole.frequency_hz * 0.000001); } // Specify fonts for changing parameters controlled by the sliders: - var normal_font = "12px arial"; + var normal_font = "14px arial"; + //var normal_font = "14px courier"; var emphasis_font = "bold 14px arial"; const emphasis_delay = 1200; @@ -218,7 +202,7 @@ var spacing_timer_handler = 0; var spacing_font = normal_font; - inductor_distance.oninput = function() { + inductor_distance_slider.oninput = function() { recalculate(); if(spacing_timer_handler == 0) { spacing_font = emphasis_font; @@ -297,15 +281,8 @@ function drawInductor(ctx, x, y, angle) { const l1 = 12.0; ctx.clearRect(x-l1,y-l1,2*l1,2*l1); - /* - ctx.beginPath(); - ctx.moveTo(x + l1*Math.cos(angle-0.25*Math.PI), y + l1*Math.sin(angle-0.25*Math.PI)); - ctx.lineTo(x + l1*Math.cos(angle+0.25*Math.PI), y + l1*Math.sin(angle+0.25*Math.PI)); - ctx.lineTo(x + l1*Math.cos(angle+0.75*Math.PI), y + l1*Math.sin(angle+0.75*Math.PI)); - ctx.lineTo(x + l1*Math.cos(angle+1.25*Math.PI), y + l1*Math.sin(angle+1.25*Math.PI)); - ctx.lineTo(x + l1*Math.cos(angle-0.25*Math.PI), y + l1*Math.sin(angle-0.25*Math.PI)); - ctx.stroke(); - */ + + // Draw box outline: ctx.beginPath(); ctx.moveTo(x + l1, y - l1); ctx.lineTo(x + l1, y + l1); @@ -314,6 +291,7 @@ ctx.lineTo(x + l1, y - l1); ctx.stroke(); + // Draw the inductor wires: const last_width = ctx.lineWidth; ctx.lineWidth = 4; const last_cap = ctx.lineCap; @@ -328,18 +306,6 @@ ctx.stroke(); ctx.lineWidth = last_width; ctx.lineCap = last_cap; - /* - ctx.beginPath(); - ctx.moveTo(x , y - l1); - ctx.arcTo(x + l1, y - l1, x + l1, y - 0.33 * l1, 0.5*l1); - ctx.arcTo(x + l1, y + 0.33 * l1, x, y + 0.33 * l1, 0.5*l1); - ctx.arcTo(x - l1, y + 0.33 * l1, x - l1, y, 0.25*l1); - ctx.arcTo(x - l1, y - 0.33 * l1, x , y - 0.33 * l1, 0.25*l1); - ctx.arcTo(x + l1, y - 0.33 * l1, x + l1, y + 0.33 * l1, 0.5*l1); - ctx.arcTo(x + l1, y + l1, x, y + l1, 0.5*l1); - ctx.lineTo(x, y + l1); - ctx.stroke(); - */ } function drawArrow(ctx, x, y, angle) { @@ -370,29 +336,17 @@ const cond_diameter_mm = dipole.cond_diameter_meters * 1000.0; const cond_diameter_inches = cond_diameter_mm / 25.4; - fctx.font = "bold 14px arial"; - fctx.textAlign = "center"; - fctx.fillText("Wire : " + (40-conductor_diameter_slider.value).toString() + "AWG : " + - "\u2300 = " + cond_diameter_inches.toFixed(4).toString() + "\" " + - "(" + cond_diameter_mm.toFixed(3).toString() + " mm)", loopx, 16); - fctx.font = normal_font; const wire_x = win_width * 0.50; - const up_wire_top_y = 40; + const up_wire_top_y = 20; const up_wire_bot_y = win_height * 0.5 - 5; const down_wire_top_y = win_height * 0.5 + 5; - const down_wire_bot_y = win_height - 40; + const down_wire_bot_y = win_height - 20; var arrow_size = 10.0; - const Xl = getInductanceFromDimensions(dipole.frequency_hz * 1e-6, - dipole.length_feet, - dipole.distance_feet, - dipole.cond_diameter_inches); - //console.log(Xl); - // Draw the top antenna element: fctx.beginPath(); fctx.moveTo(wire_x, up_wire_top_y); @@ -420,18 +374,22 @@ //fctx.fillText("0.00 ft", wire_x + 60, down_wire_bot_y ); fctx.fillText("0.00", wire_x + 60, down_wire_bot_y + 5); //drawArrow(fctx, wire_x + 10, up_wire_bot_y, -0.5*Math.PI); - const L = Xl / (2 * Math.PI * dipole.frequency_hz * 0.000001); fctx.font = emphasis_font; - fctx.fillText("L = " + L.toFixed(1).toString() + " \u00B5H", wire_x + 20, d_pos - 4); + fctx.fillText("L = " + dipole.L.toFixed(1).toString() + " \u00B5H", wire_x + 30, d_pos - 4); fctx.font = normal_font; - fctx.fillText("X = " + Xl.toFixed(1).toString() + " \u03A9", wire_x + 20, d_pos + 12); + fctx.fillText("X = " + dipole.Xl.toFixed(1).toString() + " \u03A9", wire_x + 30, d_pos + 12); fctx.font = frequency_font; - fctx.fillText("f = " + (dipole.frequency_hz * 1e-6).toFixed(2).toString() + " MHz", 20, down_wire_bot_y - 36); + + const left_spacing = 15; + fctx.fillText("f = " + (dipole.frequency_hz * 1e-6).toFixed(2).toString() + " MHz", left_spacing, down_wire_bot_y - 72); fctx.font = loop_dia_font; - fctx.fillText("l = " + (antenna_length_slider.value * 1e2).toFixed(1).toString() + " %", 20, down_wire_bot_y - 18); + fctx.fillText("l = " + (antenna_length_slider.value * 1e2).toFixed(1).toString() + " %", left_spacing, down_wire_bot_y - 54); fctx.font = spacing_font; - fctx.fillText("d = " + (dipole.spacing_ratio * 1e2).toFixed(1).toString() + " %", 20, down_wire_bot_y ); + fctx.fillText("d = " + (dipole.spacing_ratio * 1e2).toFixed(1).toString() + " %", left_spacing, down_wire_bot_y - 36); fctx.font = cond_dia_font; + fctx.fillText("AWG = " + (40-conductor_diameter_slider.value).toString(), left_spacing, down_wire_bot_y - 18); + fctx.fillText("\u2300 = " + cond_diameter_inches.toFixed(4).toString() + "\" " + + "(" + cond_diameter_mm.toFixed(3).toString() + " mm)", left_spacing, down_wire_bot_y); //fctx.textAlign = "center"; //fctx.fillText("f = " + (dipole.frequency_hz * 1e-6).toFixed(2).toString() + " MHz", wire_x, down_wire_bot_y + 30);