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Added Re slider, to capture additional external losses

pull/2/head
miguel 2021-09-22 23:12:41 +10:00
rodzic 76da27f05a
commit 9c65b3eaf2
2 zmienionych plików z 61 dodań i 10 usunięć
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2
magloop.css
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@ -98,7 +98,7 @@ section div.antennaSide-container {
section.gridLayoutClass {
display: grid;
grid-template-columns: repeat(2, 1fr);
grid-template-rows: repeat(3, 1fr) 150px 135px 300px;
grid-template-rows: repeat(3, 1fr) 150px 150px 300px;
justify-items: stretch;
}

69
magloop.html
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@ -35,6 +35,10 @@
<label for="transmit_power_slider">Tx:</label>
<input type="range" id="transmit_power_slider" min="5" max="1500" value="100" step="5">
</div>
<div class="sliders">
<label for="external_losses_slider">Re:</label>
<input type="range" id="external_losses_slider" min="0" max="1000" value="0" step="1">
</div>
<div class="radios">
<label>Met</label>
<input type="radio" name="unit_radio" id="metric_radio" value="metric" checked/>
@ -84,6 +88,10 @@
<li>c/a : is the spacing ratio; based on 'c' being the inter-winding spacing for multi-turn loops measured between conductor centers, and 'a' is the conductor diameter. (Must be >= 1.1)
A low-value will increase the resistance due to the proximity effect. (Ignore for single-turn loops.)</li>
<li>Tx : The transmit power in Watts. This affects the predicted voltage across the capacitor (Vcap), and the RMS loop current (Ia).</li>
<li>Re : Additional resistance due to external losses, due mainly from capacitor contact resistance and proximity-to-ground effects. Use Re=0.0 to assume the loop is in free-space.
Adding Re will reduce antenna efficiency, Q, Vcap and Ia, while increasing BW.
In a study [1], a 1 m diameter loop of 22 mm copper tubing at a height of 1.5 m above the ground at 7 MHz had a calculated capacitor contact resistance of ~190m&#937;
and an additional ground proximity loss resistance of ~30m&#937;. Note that ground effects are height-above-ground and frequency-dependent.</li>
<li>Metric or Imperial : selects the measuring system.</li>
<li>Cu or Al : selects the type of metal conductor (annealed copper or aluminum).</li>
<li>Circ, Oct, Hex or Sqr : selects the shape of the magloop.</li>
@ -108,7 +116,13 @@
<li>Perimeter (&#955): Antenna perimeter size relative to the wavelength.</li>
</ul>
<br>
<b><u>References:</u></b><br>
[1]: A. Boswell, A. J. Tyler and A. White, <b>"Performance of a Small Loop Antenna in the 3 - 10 MHz Band"</b> <i>, IEEE Antennas and Propagation Magazine, 47, 2, April 2005, pp. 5 1 -56.</i> <br>
<br>
<b><u>Change history:</u></b><br>
<b>[23-Sep-21]</b> <br>
* Changed Q equation back to the original Xl/Rtot.<br>
* Introduced a new slider to inject external losses to account for the combined losses due to capacitor contact resistance and ground losses.<br>
<b>[22-Sep-21]</b> <br>
* Added antenna perimeter size in wavelength to the chart display as a new item.<br>
* Changed maximum spacing ratio c/a from 4.0 to 10.0. Values higher than 4 have no further effect on proximity resistance, but does reduce coil inductance which drives up the SRF.<br>
@ -119,7 +133,7 @@
<b>[18-Sep-21]</b> <br>
* Updated to V5; Added support for octagon, hexagon and square shaped loops. Moved and hyperlinked equations-used to a separate page for clarity.<br>
<b>[16-Sep-21]</b> <br>
* Updated to V4; Updated equation used for Q to match the one use in the ARRL Antenna Book. This will affect predictions for V_cap, I_loop and BW. (Based on confirmation of correct Q equation used in
* Updated to V4; Updated equation used for Q to match the one use in the ARRL Antenna Book. This will affect predictions for V_cap, I_loop and BW. (Based on Q equation D.1 used in
<i>"Impedance, Bandwidth, and Q of Antennas"</i> by A D Yaghjian, IEEE Transactions on Antennas and Propagation, April 2005.)<br>
* Added equation graphics for V_cap, I_loop and BW formulas.<br>
* Flipped the main-loop graphic to have the capacitor above the coupling loop.<br>
@ -154,6 +168,7 @@
var metric_radio = document.getElementById("metric_radio");
var imperial_radio = document.getElementById("imperial_radio");
var shape_radio = document.getElementById("shape_radio");
var external_losses_slider = document.getElementById("external_losses_slider");
// Global variables:
var units = "metric";
@ -166,6 +181,7 @@
var loop_capacitance = 0.0; // Effective capacitance of a single or multi-turn loop
var srf = 0.0; // Self-resonant frequency SRF
var conductor_length = 0.0; // Total conductor length
var R_ext = 0.0; // External losses due to capacitor resistance and ground effects, in ohms
var frequencies = [];
@ -191,6 +207,7 @@
loop_capacitance = (loop_turns_slider.value > 1) ? multiloopCapacitance() : (2.69e-12 * perimeter);
srf = calculateSRF();
conductor_length = ((((perimeter* loop_turns_slider.value) ** 2.0) + ((loop_spacing_slider.value * conductor_diameter_slider.value * 1e-3 * loop_turns_slider.value) ** 2.0)) ** 0.5);
R_ext = external_losses_slider.value * 0.001;
}
// Returns the loop area in square meters:
@ -451,7 +468,8 @@
frequencies.forEach(freq => {
const R_ohmic = lossResistance(freq * 1e6);
const R_rad = radiationResistance(freq * 1e6);
const efficiency = 100.0 / (1.0 + (R_ohmic / R_rad));
const efficiency = 100.0 * R_rad / (R_rad + R_ohmic + R_ext);
//const efficiency = 100.0 / (1.0 + (R_ohmic / R_rad));
//const efficiency = 10.0 * Math.log10(1.0 / (1.0 + (R_ohmic / R_rad))); // for Efficiency in dB
retval.push({x:freq, y:efficiency});
});
@ -462,7 +480,7 @@
const Xl = inductiveReactance(frequency);
const Rl = lossResistance(frequency);
const Rr = radiationResistance(frequency);
const Q = Xl / (2.0 * (Rl + Rr));
const Q = Xl / (Rl + Rr + R_ext);
return Q;
}
@ -854,6 +872,36 @@
myChart.update();
}
var external_losses_handler = 0;
var external_losses_font = normal_font;
external_losses_slider.oninput = function() {
if(external_losses_handler == 0) {
external_losses_font = emphasis_font;
external_losses_handler = setTimeout(function(){
external_losses_font = normal_font;
drawFrontDesign();
external_losses_handler = 0;
}, emphasis_delay);
} else {
clearTimeout(external_losses_handler);
external_losses_handler = setTimeout(function(){
external_losses_font = normal_font;
drawFrontDesign();
external_losses_handler = 0;
}, emphasis_delay);
}
setGlobals();
drawFrontDesign();
myChart.data.datasets[1].data = calculateCapacitorVoltage();
myChart.data.datasets[2].data = calculateBandwidth();
myChart.data.datasets[3].data = calculateEfficiencyFactor();
myChart.data.datasets[7].data = calculateQualityFactor();
myChart.data.datasets[8].data = calculateCirculatingCurrent();
myChart.update();
}
window.onresize = function() {
myChart.resize();
//myChart.update();
@ -1213,7 +1261,10 @@
// Write Tx power text:
fctx.font = tx_font;
fctx.fillText("Tx = " + transmit_power_slider.value + " W", 8, win_height * 0.8 + 20);
fctx.fillText("Tx = " + transmit_power_slider.value + " W", 8, win_height * 0.8 + 10);
fctx.font = external_losses_font;
fctx.fillText("Re = " + R_ext.toFixed(3).toString() + " \u03A9", 8, win_height * 0.8 + 24);
// Write loop diameter symbol:
fctx.font = normal_font;
@ -1241,7 +1292,7 @@
fctx.fillText("A = " + area.toPrecision(3).toString() + " m\u00B2", win_width-8, 18);
// Write Tx power text:
fctx.fillText("peri = " + perimeter.toPrecision(3).toString() + " m", win_width-8, win_height * 0.8 + 20);
fctx.fillText("peri = " + perimeter.toPrecision(3).toString() + " m", win_width-8, win_height * 0.8 + 24);
} else {
fctx.font = cond_dia_font;
fctx.fillText("\u2300a = " + (cond_dia/25.4).toPrecision(3).toString() + "\"", loopx, p1y+1);
@ -1251,7 +1302,7 @@
fctx.fillText("A = " + (area * 10.76391).toPrecision(3).toString() + " ft\u00B2", win_width-8, 18);
// Write Tx power text:
fctx.fillText("peri = " + (perimeter*3.28084).toPrecision(3).toString() + " ft", win_width-8, win_height * 0.8 + 20);
fctx.fillText("peri = " + (perimeter*3.28084).toPrecision(3).toString() + " ft", win_width-8, win_height * 0.8 + 24);
}
}
@ -1323,11 +1374,11 @@
sctx.fillText((srf*1e-6).toPrecision(3).toString() + " MHz", win_width-8, win_height * 0.1 + 33);
sctx.textAlign = "right";
sctx.fillText("cond = " , win_width-8, dim_y + 08);
sctx.fillText("cond = " , win_width-8, dim_y + 10);
if(units == "metric") {
sctx.fillText(conductor_length.toPrecision(4).toString() + " m", win_width-8, dim_y + 20);
sctx.fillText(conductor_length.toPrecision(4).toString() + " m", win_width-8, dim_y + 24);
} else {
sctx.fillText((conductor_length * 3.28084).toPrecision(4).toString() + " ft", win_width-8, dim_y + 20);
sctx.fillText((conductor_length * 3.28084).toPrecision(4).toString() + " ft", win_width-8, dim_y + 24);
}
// Draw spacing text: