SSB — Single Sideband — is the primary voice mode on HF amateur radio. Understanding how it differs from FM (the mode most new licensees start on) and knowing the operating conventions that govern HF phone operation will make your first contacts cleaner, faster, and more enjoyable for everyone involved.
How SSB Differs from FM
On VHF/UHF FM, your radio transmits a constant carrier wave that varies in frequency with your voice. The receive squelch opens when it detects a carrier above the noise floor. FM is forgiving — you're either in or you're out, and the audio is relatively noise-free once the squelch opens.
SSB is fundamentally different. SSB suppresses the carrier entirely and transmits only one sideband of the audio. This makes SSB signals roughly 9 dB more efficient than AM and allows narrower bandwidth — critical on crowded HF bands. The tradeoff is that SSB is more sensitive to tuning. If you're off-frequency even 100 Hz, voices sound chipmunk-like or garbled. Always tune for natural-sounding voice before responding to a station.
On HF, the convention is LSB (Lower Sideband) below 10 MHz and USB (Upper Sideband) above 10 MHz. The crossover point means 40m and 80m voice use LSB; 20m, 17m, 15m, 12m, and 10m use USB. Virtually every HF radio auto-selects the correct sideband when you select a ham band — but know the rule in case you need to set it manually.
Essential HF Phone Frequencies
| Band | Phone Segment | SSB Calling Frequency | Notes |
|---|---|---|---|
| 80m | 3.600–4.000 MHz (USB) | 3.900 MHz | Regional, noisy evenings. LSB mode. |
| 40m | 7.175–7.300 MHz | 7.200 MHz | Most active domestic band. LSB mode. |
| 20m | 14.150–14.350 MHz | 14.225 MHz | Primary DX band. USB mode. |
| 17m | 18.110–18.168 MHz | 18.150 MHz | Less crowded DX. USB mode. |
| 15m | 21.200–21.450 MHz | 21.300 MHz | Excellent near solar max. USB mode. |
| 10m | 28.300–29.700 MHz | 28.400 MHz | Technician phone privileges here. USB. |
Making a Contact: The Procedure
Before transmitting on any frequency, listen for at least 30 seconds. HF propagation means a frequency that sounds clear to you may have two stations in contact that you simply can't hear from your location — but they can hear each other. Transmitting on an occupied frequency is poor operating practice and will earn you a polite (or not-so-polite) correction.
Check if the frequency is in use
Listen for 30 seconds. If it sounds clear, ask: "Is this frequency in use?" and pause. If no one responds, it's yours.
Call CQ
"CQ CQ CQ, this is Whiskey One Alpha Bravo Charlie, Whiskey One Alpha Bravo Charlie, calling CQ and standing by." Say your callsign phonetically. Repeat your CQ two or three times, then stand by and listen.
Respond to a station
When someone responds, give your callsign, a signal report, your name, and your QTH (location). Keep the initial exchange brief — you can elaborate once contact is established.
Signal report: RST
Give an honest RST report. On SSB, only R (Readability) and S (Signal Strength) apply — drop the T. "You're 59" means readability 5 (perfectly readable) and signal strength 9 (extremely strong). Don't always give 59 — if a station is genuinely weak or partially readable, say so. Honest reports help operators understand their propagation.
Closing the contact
End with your callsign: "This is W1ABC, 73 and thanks for the QSO." Giving your callsign at the end of each transmission is an FCC requirement when the contact spans more than 10 minutes or when ending communication.
Q-Codes in Everyday HF Phone Operation
Q-codes originated in CW operation but are widely used in SSB voice contacts, particularly for common situations where brevity matters:
- QSY: "Let's move to another frequency." "QSY up 5" means move 5 kHz up.
- QRM: Interference from another station. "I have some QRM here" means another signal is stepping on you.
- QRN: Static or atmospheric noise. Common in summer on 40m and 80m.
- QSB: Fading. "Your signal is QSB" means it's going up and down.
- QSL: Confirmation. "QSL that" or just "QSL" means "I copy/confirm."
- QRZ?: "Who is calling me?" Used when you hear a partial callsign or signal but can't make it out fully.
- QTH: Location. "My QTH is Dayton, Ohio."
Common Mistakes New Operators Make
Not listening before transmitting. Always monitor before keying up. HF skip means you may not hear a station that a station across the band can hear clearly.
Incorrect sideband selection. Using USB on 40m or LSB on 20m produces a signal other stations can't decode. Know LSB below 10 MHz, USB above.
Overdriving the microphone. Too much mic gain causes ALC (Automatic Level Control) action that distorts your transmitted audio. Most HF radios have a speech processor — use it carefully. An overprocessed signal is worse than a clean but quiet one. Ask for audio reports from other operators.
Calling CQ without listening. Find an actually clear frequency. The calling frequencies listed above are starting points, not reserved channels — confirm they're clear before using them.
Giving 59 automatically. If a station is barely copyable, saying "59" gives them useless information. "You're 53, significant QRM, readable but difficult" tells them something real.
HF Nets: Structured Operating Practice
HF nets are scheduled on-air gatherings where operators check in with a net control station and may exchange traffic (formal messages) or simply confirm their presence. Nets are excellent practice for new SSB operators — the format is structured, net control guides the flow, and you only need to transmit briefly when called. Find HF nets via the ARRL Net Directory at arrl.org/arrl-net-directory — filter by frequency, mode, and day of week.
Best way to develop SSB skills fast: Participate in a 40m or 20m ragchew net for 30 days straight. The repetition of introductions, signal reports, and comfortable conversation builds operating fluency faster than occasional solo contacts. Find a net where the operators are patient and experienced — most welcome new licensees explicitly.