.. tittel: RF Free Space Path Loss
.. slug: rf-freespacepathloss
.. dato: 2025-12-26 15:00:00 UTC
.. tags: nettverk, kalkulator, verktøy
.. kategori: Kalkulatorer
..lenke:
.. beskrivelse: Beregn tap av ledig plass (FSPL) ved hjelp av frekvens og avstand. Brukes for punkt-til-punkt mikrobølgekoblingsplanlegging og utendørs WiFi-dekningsanalyse.
.. type: tekst
<style>
    .rf-calc-container {
        max-width: 1000px;
        margin: 20px auto;
        padding: 20px;
    }

    .calc-header {
        margin-bottom: 30px;
        padding: 25px;
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        border-radius: 12px;
        box-shadow: 0 4px 6px rgba(0,0,0,0.1);
        color: white;
    }

    .calc-header h2 {
        margin-top: 0;
        color: white;
        font-size: 28px;
        margin-bottom: 10px;
    }

    .calc-header p {
        margin: 10px 0;
        opacity: 0.95;
        font-size: 15px;
    }

    .input-grid {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 15px;
        margin-top: 20px;
    }

    .form-group {
        display: flex;
        flex-direction: column;
    }

    .form-group label {
        font-size: 14px;
        margin-bottom: 8px;
        color: white;
        font-weight: 500;
    }

    .form-group input {
        padding: 14px;
        font-size: 16px;
        border: 2px solid rgba(255,255,255,0.3);
        border-radius: 6px;
        font-family: 'Courier New', monospace;
        background: rgba(255,255,255,0.95);
        transition: all 0.3s ease;
    }

    .form-group input:focus {
        outline: none;
        border-color: #4CAF50;
        background: white;
        box-shadow: 0 0 0 3px rgba(76, 175, 80, 0.1);
    }

    .submit-button {
        margin-top: 20px;
        padding: 14px 35px;
        font-size: 16px;
        background: #4CAF50;
        color: white;
        border: none;
        border-radius: 6px;
        cursor: pointer;
        font-weight: bold;
        transition: all 0.3s ease;
        box-shadow: 0 2px 4px rgba(0,0,0,0.2);
    }

    .submit-button:hover {
        background: #45a049;
        transform: translateY(-1px);
        box-shadow: 0 4px 8px rgba(0,0,0,0.3);
    }

    .submit-button:active {
        background: #3d8b40;
        transform: translateY(0);
    }

    .result-section {
        background: white;
        border: 1px solid #e0e0e0;
        border-radius: 8px;
        margin-top: 30px;
        overflow: hidden;
        box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        transition: all 0.3s ease;
    }

    .result-section:hover {
        box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    }

    .section-header {
        background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%);
        color: white;
        padding: 15px 20px;
        font-size: 18px;
        font-weight: bold;
    }

    .section-content {
        padding: 20px;
        background: #fafafa;
    }

    .data-row {
        display: flex;
        margin: 12px 0;
        padding: 10px;
        background: white;
        border-radius: 4px;
        border-left: 3px solid #4CAF50;
    }

    .data-label {
        font-weight: bold;
        color: #555;
        min-width: 300px;
        flex-shrink: 0;
    }

    .data-value {
        color: #333;
        font-family: 'Courier New', monospace;
        word-break: break-word;
    }

    .data-value.highlight {
        color: #4CAF50;
        font-weight: bold;
        font-size: 18px;
    }

    .help-text {
        margin-top: 15px;
        font-size: 14px;
        color: rgba(255,255,255,0.9);
        background: rgba(0,0,0,0.1);
        padding: 10px 15px;
        border-radius: 4px;
    }

    .help-text strong {
        color: white;
    }

    /* Responsive design */
    @media (max-width: 768px) {
        .input-grid {
            grid-template-columns: 1fr;
        }

        .data-row {
            flex-direction: column;
        }

        .data-label {
            margin-bottom: 5px;
            min-width: auto;
        }

        .submit-button {
            width: 100%;
        }
    }
</style>
<div class="rf-calc-container">
<div class="calc-header">
<h2>Kalkulator for RF-fri plassbanetap</h2>
<p>Beregn banetapet for ledig plass for radiofrekvensoverføringer basert på avstand, frekvens og antenneforsterkning.</p>
<div class="input-grid">
<div class="form-group">
<label for="distance">Avstand (km):</label>
<input id="distance" placeholder="e.g., 5" type="text" value="5"/>
</div>
<div class="form-group">
<label for="frequency">Frekvens (MHz):</label>
<input id="frequency" placeholder="e.g., 2400" type="text" value="2400"/>
</div>
<div class="form-group">
<label for="txGain">Sendende antenneforsterkning (dBi):</label>
<input id="txGain" placeholder="e.g., 0" type="text" value="0"/>
</div>
<div class="form-group">
<label for="rxGain">Mottaksantenneforsterkning (dBi):</label>
<input id="rxGain" placeholder="e.g., 0" type="text" value="0"/>
</div>
</div>
<button class="submit-button" onclick="freeSpacePathLoss()" type="submit">Kalkulere</button>
<div class="help-text">
<strong>Note:</strong>Tap av ledig plass representerer signaldempingen mellom sender og mottaker i et ideelt miljø uten hindringer. Antenneforsterkninger legges til for å kompensere for banetap.</div>
</div>
<div class="result-section" id="results" style="display: none;">
<div class="section-header">Resultater</div>
<div class="section-content">
<div class="data-row">
<div class="data-label">Tap av ledig plassbane (lineær):</div>
<div class="data-value highlight" id="fsplResult">-</div>
</div>
<div class="data-row">
<div class="data-label">Mottatt kraftstyrke (dB):</div>
<div class="data-value highlight" id="fsplResultindB">-</div>
</div>
</div>
</div>
</div>
<script>
function freeSpacePathLoss() {
    // Set variables from input
    var distance = Number(document.getElementById("distance").value);
    var frequency = Number(document.getElementById("frequency").value);
    var pi = Math.PI;

    var txGain = Number(document.getElementById("txGain").value);
    var rxGain = Number(document.getElementById("rxGain").value);

    // Free Space Path Loss
    var fspl = (Math.pow((4*pi*distance*frequency)/299792458,2))-txGain-rxGain;

    // Free Space Path Loss in dB
    var fsplResultindB = (20*Math.log10(distance)+20*Math.log10(frequency)+32.44)-txGain-rxGain;

    // Print results
    document.getElementById("fsplResult").innerHTML = fspl.toFixed(6);
    document.getElementById("fsplResultindB").innerHTML = fsplResultindB.toFixed(2) + " dB";

    // Show results section
    document.getElementById("results").style.display = "block";

    // Scroll to results
    document.getElementById("results").scrollIntoView({ behavior: 'smooth', block: 'start' });
}

// Add enter key support for all input fields
document.addEventListener('DOMContentLoaded', function() {
    const inputs = ['distance', 'frequency', 'txGain', 'rxGain'];
    inputs.forEach(function(id) {
        document.getElementById(id).addEventListener('keypress', function(e) {
            if (e.key === 'Enter') {
                freeSpacePathLoss();
            }
        });
    });

    // Auto-focus first input field
    document.getElementById('distance').focus();
});
</script>