Unofficial compilation note: this library is unofficial material compiled and rewritten by BG7BAG Radio from public sources, for study reference only, and is not affiliated with the equipment manufacturers. For takedown requests, contact contact@bg7bag.com.
UV-5R CTCSS / DCS Tones
Understand tones to reliably open repeaters and avoid "hear but not heard".
What are sub-audible tones
CTCSS (Continuous Tone-Coded Squelch System) is an analogue sub-tone that opens squelch only when a specific low tone is present; DCS is the digital version (code). They reduce interference and let a repeater respond only to authorised users.
Set the transmit tone (most common)
Steps: Frequency Mode → MENU 13 MENU choose T-CTCS → enter the tone (e.g. 0885 = 88.5 Hz) → MENU to save. This is the key to “let the repeater hear you”.
Set the receive tone
MENU 11 MENU choose R-CTCS. Note: only enable it when you want to hear only signals carrying that tone. For everyday repeater use, set the transmit tone only and leave receive OFF — otherwise you’ll “not hear others”.
DCS digital tone
Menu 12 T-DCS (transmit) / 10 R-DCS (receive). DCS uses a 3-digit code (e.g. 023, 754). Pick CTCSS or DCS per the repeater’s requirement.
Practical tip
!
“Hear but not heard” is almost always a missing transmit tone; “total silence” is almost always a receive tone left on. Telling them apart fixes 90% of tone issues.
CTCSS or DCS — which to use?
Whatever the repeater requires. Most analogue repeaters use CTCSS; some use DCS. Follow the listing.
What is TSQL?
TSQL = same tone for transmit and receive. In CHIRP, set Tone Mode to TSQL.
Where do I find the tone value?
Published by the repeater listing/trustee — common values 67.0 / 88.5 / 100.0 / 103.5 / 114.8 / 156.7 Hz.