Scanning
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This page groups all scan-related features: frequency scan, memory scan, scan lists, ScnRng, frequency copy, and DCS / CTCSS scanning.
For day-to-day VFO/channel operation, see Radio operation. For spectrum sweep usage, see Spectrum analyzer.
- Frequency scanning
- Memory channels scanning
- Scan engine mode: NORMAL vs FAST
- Scan indicators and detection
- Frequency copy and DCS / CTCSS scanning
- Related pages
Tip
If memory scan seems broken, the most common cause is an empty active scan list. See Troubleshooting for the quick checks.
To start a frequency scan, switch a VFO to frequency mode. Set a start frequency. Set a frequency step (menu Step). Start scanning with a custom scan button function or by long-pressing the * Scan button.
- switch to frequency mode
- set the upper and lower VFO frequencies to the scan range boundaries
- long-press
5 NOAA; theScnRnglabel should appear - start the scan by long-pressing
* Scan - the radio will scan between the selected boundaries
- long-press
5 NOAAorEXIT, or switch VFOs, to exitScnRngmode
The ScnRng function is also supported by the spectrum analyzer. If you have already enabled ScnRng, just start the spectrum analyzer.
If you use Air Copy and transfer Settings, the VFO area is included. This also copies the source radio's current ScnRng boundary frequencies to the target radio.
While a ScnRng scan is stopped on a received frequency, long-press MENU to exclude that frequency from the current range scan.
Up to 64 range-scan frequencies can be excluded. The list is circular: after 64 exclusions, adding another one replaces the oldest stored exclusion.
These exclusions are temporary. They are kept only for the active ScnRng setup and are not written to memory. They are cleared if the radio is restarted, and they are also cleared when the range identity changes: start frequency, stop frequency, or scan step.
Memory scan lets the radio scan saved memory channels instead of stepping through frequencies.
To use it, switch the VFO to Memory mode, then start scan with a programmed scan key or by long-pressing * Scan.
The radio provides 24 scan lists. Each memory channel can be assigned to:
-
OFF: the channel is excluded from scan lists -
1to24: the channel belongs to one specific scan list -
ALL: the channel is included in all scan lists
A memory channel can belong to only one of these states at a time.
To change the scan-list assignment of the current memory channel:
- open the
ScListmenu - or long-press
5 NOAAfor the quick assignment shortcut
The quick shortcut cycles the channel through:
OFF-
1to24 ALL
The current assignment is shown to the right of the channel name.
Scan lists can have short names.
When a list has a name, the radio shows that 3-character name instead of the numeric list number where possible:
- in scan-related status indicators
- in list selection menus
- in the channel list-assignment display
If a list has no name, the radio shows the list number instead.
Memory scan always uses one active scan list.
The currently active list is shown at the top-left of the screen while scanning:
-
01to24for a numbered list -
ALLfor all listed channels
If the selected list has a name, that short name is displayed instead of the number.
If the selected list is empty or invalid, the radio automatically switches to the next valid, non-empty list.
Once channels have been assigned to lists, start memory scan by:
- using a key assigned to the scan function
- or long-pressing
* Scan
The radio then scans the memory channels that belong to the currently active scan list.
The active scan list can be changed without stopping the scan.
- long-press
* Scan: switch to the next valid non-empty scan list -
F + navigation key: browse through scan lists while scanning (UP/DOWNon UV-K5,LEFT/RIGHTon UV-K1) - keypad direct entry:
-
01to24: select that scan list directly -
00: selectALL
-
If the requested list is empty, the radio beeps and jumps to the next valid, non-empty list.
While scanning, press a navigation key:
-
UP/DOWNon UV-K5 -
LEFT/RIGHTon UV-K1
This reverses the direction used to step through memory channels in the current scan list.
The radio supports two priority channels:
PriCh1PriCh2
These are configured in the menu and controlled by the ScPri setting.
When priority scan is enabled, the radio does not simply scan channels in list order. Instead, it repeatedly inserts the priority channels into the scan cycle.
The scan sequence becomes:
PriCh1PriCh2- next regular channel from the active scan list
This cycle then repeats continuously.
This allows the radio to check the two priority channels more often than regular channels, so activity on them is detected faster.
When priority scan is enabled:
- priority channels are handled separately from normal list scanning
- if a priority channel also belongs to the active scan list, it is removed from the regular scan path to avoid being scanned twice
- priority channels can still be checked even if they are outside the normal list progression
When the scanner finds activity on a channel, what happens next depends on the ScnRev setting.
Depending on this setting, the radio may:
- resume scanning automatically after a delay
- remain stopped on the active channel until scan is restarted manually
Pause and resume behavior are therefore controlled by the scan resume mode, not by the scan list itself.
While memory scan is stopped on a received memory channel, long-press MENU to exclude that channel from future memory scans.
This exclusion is temporary.
The channel remains excluded until the next restart of the transceiver.
If you switch off the transceiver while it is scanning, the scan will automatically resume the next time you restart it.
The following controls apply to both frequency scan and memory scan:
- press a navigation key while scanning to reverse the scan direction (
UP/DOWNon UV-K5,LEFT/RIGHTon UV-K1) - press
EXITto stop scan and return to the frequency or channel that was selected before scan began - press
PTTorMENUto stop scan and keep the last frequency or channel where activity was found
Builds with fast scan support add the SetScn menu. It selects the scan engine used by memory scan and ScnRng.
NORMAL uses the standard scan path. Each frequency or memory channel is fully applied to the radio, with normal VFO configuration, squelch/output-power setup, receiver register setup, and the usual scan pause timing.
This mode is the most conservative choice. It is useful if you prefer the older scan behavior or want to compare results against the fast engine.
FAST is the default mode in current builds. It adds a lightweight RSSI pre-check before the full receive setup:
- for memory scan, the firmware probes the next channel frequency and skips it quickly if it is clearly quiet
- for
ScnRng, the firmware probes a small batch of range steps before doing a full tune - quiet batches are skipped faster, so scanning spends less time on empty spectrum
- possible signals are promoted back to the normal full receive path, so squelch and normal scan-resume behavior still decide what happens next
- in
ScnRng, fine steps can be refined around a candidate so the scan lands closer to the strongest nearby signal - if the scan loop stalls after the normal
ScnRevpause has expired, a short watchdog resumes scanning
The fast pre-check learns a local RSSI noise floor and compares each probe against that floor and the configured squelch threshold. If squelch is fully open, or if the fast path cannot safely pre-check a channel, the firmware falls back to the normal full tune for that step.
Note
In ScnRng, FAST mode can scan around 150+ frequencies per second in favorable conditions, especially when most of the range is quiet and the scan can skip silent batches without doing a full receive setup for every step.
Plain frequency scan outside ScnRng still advances one frequency step at a time; SetScn = FAST mainly changes memory scan and scan-range behavior.
Current fast-scan builds can show a small RSSI sparkline while scanning. It is a compact history of recent RSSI samples; quiet samples stay low, while stronger candidates stand out as taller marks.
During memory scan, the scan-list indicator keeps showing the active list:
-
01to24 ALL- the 3-character scan-list name, when the list has one
When priority scan is enabled, a + is appended to the scan-list indicator.
During ScnRng, builds with subaudible scan-range support can detect CTCSS / DCS while the radio is stopped on a received signal. If a code is found, the scan UI can show the detected tone or DCS code together with the received frequency.
The scan display also refines the placement of the VFO lock indicator while scanning, so TX-lock state remains visible without overlapping the active scan information.
This function lets you detect and copy frequency and coding settings. The frequency search works only for strong signals, so the transmitting radio has to be close. To start frequency copy (FC), use the 4 FC function button. The scanner screen will open. Push and hold the PTT button on the other radio. Wait a couple of seconds until the frequency and code (if used) appear on the screen. The settings can be saved with the MENU button. They will be saved either to a channel or to the main VFO, depending on which mode you started the scan in.
In current builds, the scanner screen makes the state more explicit:
-
Search Freq: frequency search is running -
Search Tone: subaudible tone/code search is running -
Scan Complete: a result was found -
Scan Failed: no usable result was found -
Freq:shows the detected frequency -
Tone:/CTCSS:/DCS:shows the detected subaudible setting when one is found
You can also search only for the DCS / CTCSS code for a frequency set on the main VFO. Choose the desired frequency or channel and press F + * SCAN. The same screen will appear, but the frequency search will be omitted; the frequency of the main VFO will be used instead. Wait for a signal to appear or press the PTT on the other radio. It takes 1 to 2 seconds for the code to be found. The save procedure is the same as above.
There is another way to scan for a DCS / CTCSS code. Choose the desired frequency or channel. Go to the RxDCS or RxCTCS menu. Enter the menu option and press the * SCAN button. A SCAN label will appear. Wait for a radio signal or press the PTT button on the other radio. When the code is found, the SCAN label will disappear. To save it, confirm the option with the MENU button. It does not matter which of the two menu items you start from: both DCS and CTCSS can be found, and the menu entry will be changed to the correct one.