.. title: RF 自由空間パス損失
.. スラグ: rf-freespacepathloss
.. 日付: 2025-12-26 15:00:00 UTC
.. タグ: ネットワーキング、電卓、ツール
.. カテゴリ: 電卓
..リンク:
.. 説明: 周波数と距離を使用して自由空間経路損失 (FSPL) を計算します。ポイントツーポイントのマイクロ波リンク計画と屋外 WiFi カバレッジ分析に使用されます。
.. タイプ: テキスト
<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>RF自由空間経路損失計算機</h2>
<p>距離、周波数、アンテナ ゲインに基づいて、無線周波数伝送の自由空間パス損失を計算します。</p>
<div class="input-grid">
<div class="form-group">
<label for="distance">距離 (km):</label>
<input id="distance" placeholder="e.g., 5" type="text" value="5"/>
</div>
<div class="form-group">
<label for="frequency">周波数 (MHz):</label>
<input id="frequency" placeholder="e.g., 2400" type="text" value="2400"/>
</div>
<div class="form-group">
<label for="txGain">送信アンテナ利得 (dBi):</label>
<input id="txGain" placeholder="e.g., 0" type="text" value="0"/>
</div>
<div class="form-group">
<label for="rxGain">受信アンテナ利得 (dBi):</label>
<input id="rxGain" placeholder="e.g., 0" type="text" value="0"/>
</div>
</div>
<button class="submit-button" onclick="freeSpacePathLoss()" type="submit">計算する</button>
<div class="help-text">
<strong>注記：</strong>自由空間経路損失は、障害物のない理想的な環境における送信機と受信機間の信号の減衰を表します。パス損失を補償するためにアンテナ ゲインが追加されます。</div>
</div>
<div class="result-section" id="results" style="display: none;">
<div class="section-header">結果</div>
<div class="section-content">
<div class="data-row">
<div class="data-label">自由空間経路損失 (線形):</div>
<div class="data-value highlight" id="fsplResult">-</div>
</div>
<div class="data-row">
<div class="data-label">受信電力強度 (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>