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RS-UV3A

Frequency Commands

F – Set Frequency

Section titled “F – Set Frequency”

Sets the transmit and/or receive frequency.

Syntax

Section titled “Syntax”
Fz nnnnnn
F?

Parameters

Section titled “Parameters”
ParameterDescription
zMode selector (see below)
nnnnnnFrequency in kHz (all 6 digits required)

Mode selectors:

ModeDescription
RSet RX frequency only
TSet TX frequency only
SSet both TX and RX to same frequency (simplex)
DSet RX to frequency, TX to frequency minus standard offset
USet RX to frequency, TX to frequency plus standard offset

Standard repeater offsets:

  • 2m band: 600 kHz
  • 1.25m band: 1600 kHz
  • 70cm band: 5000 kHz

Examples

Section titled “Examples”
FS146520        # Simplex on 146.520 MHz
FD146940        # RX 146.940, TX 146.340 (-600 kHz)
FU147060        # RX 147.060, TX 147.660 (+600 kHz)
FR223500        # Set RX only to 223.500 MHz
FT222900        # Set TX only to 222.900 MHz
F?              # Query current frequencies

Response

Section titled “Response”

F? returns:

RX: 146520
TX: 146520

Notes

Section titled “Notes”
  • Frequency range: 136-174 MHz, 200-260 MHz, 400-520 MHz
  • The RS-UV3A is designed to transmit only on amateur frequencies
  • TX outside amateur bands may have reduced power due to filtering
  • Firmware 2.4+ supports 0.5 kHz steps by adding 5 to frequency

0.5 kHz Steps (Firmware 2.4+)

Section titled “0.5 kHz Steps (Firmware 2.4+)”

For frequencies like 146.5225 MHz:

FS1465225       # 146.5225 MHz (note: 7 digits)
Section titled “Related Commands”
  • FM — Measure signal on a frequency
  • ST — Store current frequency
  • RC — Recall stored frequency

FM – Measure Signal

Section titled “FM – Measure Signal”

Tunes to a frequency, measures signal strength, and returns to the original frequency.

Syntax

Section titled “Syntax”
FMnnnnnn

Parameters

Section titled “Parameters”
ParameterDescription
nnnnnnFrequency in kHz (all 6 digits required)

Examples

Section titled “Examples”
FM146520        # Measure signal on 146.520 MHz
FM445000        # Measure signal on 445.000 MHz

Response

Section titled “Response”

Returns signal strength in dBm:

FM: -95

Notes

Section titled “Notes”
  • Measurement takes approximately 100 ms
  • Returns to original frequency after measurement
  • Useful for channel activity monitoring
  • Can be used to build a basic spectrum display with a controller
  • Signal level is raw RSSI, not calibrated to a specific standard

Applications

Section titled “Applications”

Channel scanning:

FM144390        # Check APRS frequency
FM146520        # Check calling frequency
FM146940        # Check local repeater

Signal survey: Use with an Arduino or other controller to scan frequencies and log signal levels for propagation studies or interference hunting.

Section titled “Related Commands”
  • F — Set operating frequency
  • SS — Read current signal strength