Getting Started

Getting Started with UV-K5

What's Different in rfsplatter Firmware

rfsplatter v0.1 is based on the egzumer fork of the open-source Quansheng UV-K5 firmware. It includes all egzumer features (spectrum analyzer, AM fix, wide RX, SSB/USB reception) plus several additions specific to rfsplatter:

  • Band labels on VFO display — The VFO info line shows a short band name (2M, 70cm, AIR, SW/6M, VHF+, 350, UHF+) based on the current frequency, making it easier to know your operating band at a glance.
  • Radio-to-radio text messaging — A built-in messenger lets UV-K5 radios exchange short text messages over FM frequencies using FSK. Supports T9 input, broadcast (CQ) mode, and directed messages with automatic acknowledgment. See the Messaging Guide.
  • Custom splash screen — Upload your own 128×64 monochrome image at rfsplatter.com/build and it will be compiled into the firmware and shown at boot.
  • RFSPLATTER v0.1 branding — The boot screen and version string identify the firmware as RFSPLATTER v0.1, distinguishing it from stock or other community builds.
  • Based on egzumer fork — All egzumer features are included: spectrum analyzer, AM fix, wide RX (18 MHz–1.3 GHz), SSB/USB reception, improved scanning, DTMF decoding, and more.
Main VFO showing band labels 2M and 70cm on VFO info lines
rfsplatter band labels — VFO A shows "2M" on 146.520 MHz, VFO B shows "70cm" on 446.000 MHz

What is the UV-K5?

The Quansheng UV-K5 is an inexpensive handheld transceiver covering 50 MHz – 600 MHz. It transmits on VHF (136–174 MHz) and UHF (400–470 MHz) and can receive across a much wider range, including AM aircraft band (108–136 MHz), FM broadcast (76–108 MHz), and more.

rfsplatter firmware replaces the stock Quansheng software with a community-developed alternative that adds the spectrum analyzer, extended receive coverage, USB/SSB reception, improved scanning, DTMF decoding, a flashlight, and dozens of other features — all configurable from rfsplatter.com.

Powering On & Volume

Boot screen showing RFSPLATTER v0.1
Boot screen shown while the radio initializes
  • Power/Vol knobRotate clockwise to power on. Continue rotating to increase volume. Rotate counter-clockwise to decrease volume; turn past minimum to power off.
  • VolumeAdjust the knob at any time during normal operation. The audio level indicator on the center bar shows the current level during TX.
Keypad locked — long press # to unlock
Keypad locked — long press # to unlock
Low battery warning
Low battery warning

Display Layout Overview

Main VFO display — dual frequency view
Main VFO screen — VFO A active on 146.520 MHz FM, VFO B on 446.000 MHz FM

The display is split into five zones from top to bottom:

ZoneContents
Status barTX/RX indicator, scan mode, dual watch, VOX, key lock, F-key active, battery level
VFO A — line 1VFO marker (▲/▼), TX/RX icon, channel number or frequency, scan list icons
VFO A — line 2Modulation (FM/AM/USB), power (L/M/H), offset, reverse, bandwidth (W/N), DTMF, scrambler, signal bars
Center lineRSSI bar with dBm + S-unit, audio bar during TX, DTMF decode, charge level during charging
VFO B — lines 1 & 2Same layout as VFO A

See the Display Guide for a full breakdown of every icon and indicator.

VFO Mode vs Channel Mode

The radio operates in one of two modes per VFO:

  • VFO Mode — Displays a raw frequency. You can tune directly by entering digits on the keypad, change steps, and adjust modulation, power, and tones freely. Changes are temporary.
  • Channel Mode — Recalls a stored memory channel (0–199). All settings (frequency, name, tones, power, scan lists) come from the channel. Great for programmed repeaters and nets.
F + 3Toggle between VFO mode and channel mode for the active VFO.

Tuning by Frequency Entry

In VFO mode, type a frequency directly on the numeric keypad. The radio accepts digits as you type and jumps to the frequency when all digits are entered.

  • Enter 1 4 6 5 2 5 to go to 146.525 MHz.
  • Frequencies are entered in MHz with implied decimal: 6 digits total for MHz (e.g., 146.525) or 7 digits for kHz (e.g., 446.000).
  • Press EXIT to cancel an in-progress entry.
  • Use the up/down arrow keys to step through frequencies in the current step size.

Band Selection

Quickly jump to the start of a band using the band shortcut.

F + 1Open the band selector. Use up/down arrows to choose a band, then press MENU to confirm. Available bands depend on firmware configuration.

Switching Between VFO A and B

The radio has two independent VFOs — A (upper) and B (lower). The active VFO (shown by the triangle marker ▲ or ▼) responds to tuning, scanning, and transmit actions.

F + 2Switch the active VFO between A and B. The triangle marker moves to indicate which is active.

Basic Transmitting

  • Press and hold PTT to transmit. The TX indicator appears on the display.
  • Release PTT to return to receive.
  • Transmission requires: sufficient battery, no active TX lock, frequency within an allowed TX band.
  • Power level is shown in VFO line 2: L (Low), M (Mid), or H (High).
  • Quick-toggle power with F + 6.

See the Transmission Guide for repeater setup, CTCSS/DCS, VOX, and TX restrictions.

Basic Receiving

  • The radio monitors the active VFO frequency continuously. When a signal breaks squelch, audio plays through the speaker.
  • The center bar RSSI graph shows signal strength in real time even when squelch is closed.
  • If you hear nothing on a busy frequency, the squelch may be too tight. Lower it via the SQL menu item (0 = open, 9 = tightest).
  • For weak or marginal signals, try squelch level 1 or 0 (open squelch).
  • For aircraft, switch to AM modulation. For amateur SSB, switch to USB mode.

See the Reception Guide for modulation modes, AM Fix, Dual Watch, and S-meter details.

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