Understanding UHF, VHF, AM, and FM in the F/A-18C Hornet
Effective radio communication in the F/A-18C Hornet depends not only on proper frequency presets but also on understanding the radio bands and modulation types used: UHF, VHF, AM, and FM. These terms describe how and where a signal is transmitted and received.
📡 Radio Bands: UHF and VHF
| Band | Frequency Range | Use in F/A-18C | Notes |
|---|---|---|---|
| UHF (Ultra High Freq.) | 225.000 – 399.975 MHz | Primary for military ATC, AWACS, strike coordination, and aircraft-to-aircraft comms | Most default military channels are UHF |
| VHF (Very High Freq.) | 30.000 – 174.000 MHz | Used for ground comms (JTAC), ATC (civilian), and some regional towers | VHF is often used for ground-based ops or coalition forces |
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The ARC-210 radios in the F/A-18C can operate in both UHF and VHF bands. Frequencies are manually entered or selected via preset channels.
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Most airborne assets (AWACS, tankers, flights) will use UHF.
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Ground-based assets (JTAC, civilian ATC, regional towers) may use VHF.
🎚️ Modulation Types: AM and FM
| Modulation | Use Case | Supported in F/A-18C | Notes |
|---|---|---|---|
| AM (Amplitude Modulation) | Standard for aviation comms | ✔ Yes | Used for most UHF/VHF radio calls (ATC, AWACS, flights) |
| FM (Frequency Modulation) | Ground forces, JTAC, and CAS | ✔ Yes | Typically used in VHF band (30–88 MHz); more resistant to static/interference |
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AM is default and is used for nearly all aviation communications in DCS.
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FM is used when talking to JTACs or ground units via VHF (e.g., 30.00–76.00 MHz). The ARC-210 supports this, and DCS will auto-modulate based on frequency.
🛠️ How to Know What You're Using
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When tuning radios in DCS, you don’t explicitly select AM or FM—the modulation is determined by the frequency entered.
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Example:
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251.000→ UHF AM -
30.000→ VHF FM -
127.500→ VHF AM
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As a rule:
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Above 108 MHz = AM
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Below 88 MHz = FM
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Between 108–174 MHz = AM unless specifically in FM JTAC band
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✅ Quick Comms Summary
| Frequency | Band | Modulation | Typical Use |
|---|---|---|---|
| 251.000 | UHF | AM | AWACS / Tower |
| 127.500 | VHF | AM | Carrier ATC / Civil ATC |
| 30.000 | VHF | FM | JTAC / Ground troops |
| 320.000 | UHF | AM | Strike package net |
| 268.000 | UHF | AM | Tanker (Texaco) |
🧠 In Practice (DCS Tips)
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Use AM for all aircraft/airfield comms unless you're talking to JTAC or infantry units.
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If using SRS (Simple Radio Standalone), make sure your SRS settings allow auto modulation switching based on frequency.
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The Hornet’s radios do not allow manually selecting modulation type—it’s automatic based on freq.