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qFT8 User Manual

Table of Contents

Disclaimer of Liability: By using qFT8, you assume all responsibility for legal compliance, safety, and equipment damage

What is qFT8?

qFT8 is an Android phone app for amateur radio that decodes and transmits FT8, FT4, FT2, LQ8, JS8, or WSPR digital data messages using a transceiver.

qFT8 Camera qFT8 Screenshot

Although qFT8 features out-of-the-box (plug-and-play) support for the QMX and ICOM 7300, you may also use it with any transceiver by placing the phone close to the speaker and microphone with VOX enabled, or using an audio link cable. You may also just try qFT8 without a transceiver: it transmits using the phone speaker and listens to signals using the phone microphone. Several phones running qFT8 can contact each other via audio when they are close enough.

qFT8 is a free app and does not contain ads. The license for its source code will be decided when the source code is released (LICENSE).

Luis Quesada Torres (HB9IPH) developed qFT8 in 2026, owns the copyright, and reserves all rights.

qFT8 includes parts from usb-serial-for-android (Copyright © 2011-2020 Google Inc., Mike Wakerly, Andreas Butti, Kai Morich, BSD-3-Clause), Roboto (Copyright © 2015 Google Inc. / Christian Robertson, Apache-2.0), Roboto Mono (Copyright © 2015 Google / The Roboto Mono Project Authors, OFL-1.1), Natural Earth (Public Domain), hamradio-zones-geojson (Copyright © 2024 HB9HIL, HA8TKS, MIT license), Big CTY (Copyright © Jim Reisert AD1C), and Eclipse Temurin (OpenJDK) Java Runtime (Copyright © Oracle and/or its affiliates and other contributors, GPLv2 with the Classpath Exception). None of these third-party authors or projects endorse or are affiliated with qFT8.

Key Features

Supported Devices

qFT8 supports three main ways of connecting your transceiver:

Direct CAT/Audio Transceivers (USB Cable Control)

These transceivers are directly supported via a USB cable, which handles both CAT control (for frequency tuning and PTT keying) and high-quality USB audio transmission:

Note on External Interfaces (Digirig, generic USB-serial cables): Auto-detection (AUTO) is designed for transceivers with native USB controllers or model-branded cables. When using a generic external interface (like Digirig), auto-detection only sees the generic interface chip and defaults to VOX mode. To use CAT control with radios connected via external interfaces (e.g., Lab599 TX-500), please manually select your transceiver model in the Transceiver Settings menu.

More devices are supported via VOX, which is a partial audio-only integration.

Note: For safety reasons, qFT8 does not allow changing the Tx power of the transceiver. Adjust power manually in your transceiver.

Other transceivers

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Quick Setup

Please ensure that you are using the right power supply for the transceiver (e.g. ≤12V for a QMX) or you will damage it.

Please also ensure that the USB cable and adapter you are using to connect the phone and the transceiver is rated for data transfer. Note that for devices that use connectors other than USB-C, a specific OTG (on-the-go) cable is often required. Most connectivity issues where qFT8 doesn't see the transceiver are due to using an incompatible cable or adapter.

Some Android devices have USB OTG disabled by default. This must be enabled in your device settings (the option may be hidden in advanced, system, or additional settings). If you are having connection issues—in particular if you are able to receive signal from qFT8 but not transmit and CAT commands don't work even when the device is fully supported (shown in the device dropdown, autorecognized in AUTO mode, etc.)—this is very likely the cause.

Grant Initial Permissions

When opening qFT8 for the first time, it will request several permissions:

Key Principle: qFT8 does not submit any information to a server dedicated to this app. All data processing happens locally on your device. You may explicitly authorize sharing callsign, date and time, and optionally approximate location if you enter a valid QRZ API Key.

For more details, see the qFT8 Privacy Policy - License.

Enter Callsign

Inputting a callsign is mandatory for qFT8 to function. If you do not intend to connect to an actual transceiver, any callsign can be input for testing purposes, e.g. XX1XXX.

qFT8 will ask you to input your callsign and acknowledge the following:

Grant USB Connection Permission

When the transceiver is plugged in and qFT8 is open, a system dialog will appear:

"Open qFT8 to handle Transceiver."

If you have issues connecting the Android device, check the Android device doesn't recognize the transceiver or it gets disconnected troubleshooting section.

qFT8 automatically configures the transceiver whenever it is connected.

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[QMX Only] Audio Check

Before you start operating, it is important to verify that the audio signal between your phone and the QMX is working correctly. Press the TX button and wait for the QMX to start transmitting in one of the next sequences.

Everything is working

If the TX button shows power output (e.g. 5W), everything is working correctly. On the QMX LCD, you should see a bar under the "A" VFO marker at the top-left of the screen — this means the QMX is receiving a good audio signal from the phone. You should also confirm that there is no "S" shown after the frequency on the LCD, which would indicate SWR protection.

"S" shown after the frequency

If the QMX LCD shows an "S" after the frequency, it means SWR protection has engaged. Your antenna is not properly tuned for the current band. You can use the SWR check option in the QMX menu to measure the SWR and will need to tune your antenna.

Two dots instead of a bar

If the QMX shows two dots instead of a bar under the "A" VFO marker at the top-left of the screen, the audio volume is either too low or too high.

Try: Go to qFT8 Settings, find the "Set system volume to [X] when transmitting" option, and try different values (e.g. 70%, 80%, 60%, 100%). One of these should turn the two dots into a bar.

On some phones, this option may not work. In that case, uncheck it and manually adjust your phone volume to different values (100%, 90%, 80%, etc.) until the bar appears.

Also, common-mode current may be impacting the QMX behavior, and adding a common-mode choke to the antenna may help with audio issues as well.

Nothing under the "A"

If there is no bar and no dots under the "A" VFO marker at the top-left of the QMX LCD screen, the phone may not be properly controlling the transceiver. This usually means USB permissions were not granted or were accidentally dismissed. Receiving will work, but transmitting will not.

Try: Unplug the QMX from the phone and plug it back in — the permission dialog should appear again. It may also be that the cable is not suitable for the QMX; try a different USB-C cable.

Once you see a bar under the "A" VFO marker at the top-left of the QMX LCD screen and power output in the TX button, your QMX is properly set up and ready to operate!

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[Optional] Import QSOs

You may now import your existing QSOs; there are two approaches. Both ways require going to settings using the right-most button in the bottom bar of qFT8.

qFT8 Camera qFT8 Settings Button

The manual approach: Go to the "ADIF File Import" section in settings, click the "IMPORT QSOs" button, and select the .adi file to import.

qFT8 Camera qFT8 ADIF Import

The QRZ automatic approach: Requires an active QRZ paid subscription. Go to the "QRZ Syncing" section in settings, enter the QRZ API Key for your callsign, press "VALIDATE", and then click the "IMPORT QSOs FROM QRZ" button. This will also set up automated uploads to QRZ and confirmation checks.

qFT8 Camera qFT8 QRZ Syncing

The LoTW automatic approach: Free of charge. Go to the "LoTW Syncing" section in settings, enter your Callsign and LoTW password, and enable background synchronization if desired. This will also allow you to perform the initial "IMPORT QSOs FROM LoTW".

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Your First QSO With qFT8

Note: Accurate time is critical for FT8. qFT8 automatically synchronizes time upon app initialization via NTP (internet) or GPS (satellites). If you are operating in the field without internet access, you can use the GPS SYNC button in the Settings tab to synchronize your clock directly from GPS satellites. This requires precise location permission and a clear view of the sky.

At this point, the transceiver should be connected to the right power supply and the antenna, and all permissions should be granted. Make sure that the antenna is tuned to a band with a reasonable SWR (ideally consistently below 2) that will not trigger SWR protections. It is a bad idea to disable SWR protection in the QMX; it could damage the finals or the antenna tuner.

You may now choose the band you want to use in the bottom bar of qFT8 or in the transceiver. Setting it in one of them will sync it to the other.

qFT8 Camera qFT8 Band Selector

At this point, the spectrogram will show signals and start decoding messages, and the Stations tab will be updating with the stations you're hearing.

qFT8 Camera qFT8 Stations Button

Pressing the TX button (left-most button in the bottom) will enable transmission.

If everything is correct, the TX button will eventually light up with "TX Transmitting" and will show the transmission power and SWR (e.g., "5.0W SWR 1.2").

qFT8 Camera qFT8 TX Button

Given the "AUTO" mode is selected by default, qFT8 will start making QSOs and logging them in the Log tab.

qFT8 Camera qFT8 Log Button

You may tap in the spectrogram to change the Tx frequency offset (additionally, tapping on the top part of the spectrogram, where the peak indicators are, allows you to input a frequency manually), you may change sequence by tapping the 0 and 1 buttons in the bottom bar, you may tap the different "CALL" buttons to call specific stations, or you may tweak the bar with the "AUTO" button in the Stations tab to decide on the strategy. More on all of these advanced features in the following sections.

Note that qFT8 will start calling stations or, if none of them are reachable, will start calling CQ. Eventually, if everything is properly set up and the propagation is good, qFT8 will achieve QSOs.

If qFT8 is not receiving proper signals and not decoding messages, that is a clear sign that something is wrong: propagation in that band may be closed, the antenna may not be properly tuned, the antenna may not be properly connected to the transceiver, the transceiver may not be properly connected to the phone, or some of your equipment may not be functioning correctly. See the troubleshooting section below for common issues.

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Intro to digital modes

Amateur radio digital modes encode text and data into audio frequency-shift keying (FSK) tones transmitted over single-sideband (SSB) radio. Combining narrow bandwidths, advanced forward error correction (FEC), and strict time synchronization, digital modes enable reliable worldwide communication even when signals are buried deep below the audible noise floor. qFT8 supports the leading modern digital modes—FT8, FT4, FT2, JS8, WSPR, and LQ8—each engineered for distinct operational goals ranging from ultra-weak-signal propagation beaconing to rapid contesting and conversational keyboard-to-keyboard messaging.

FT8

FT8 (Franke-Taylor design, 8-GFSK) is the world's most widely used weak-signal digital protocol, engineered for challenging HF/VHF conditions, multi-hop sporadic-E, and crowded bands. It operates with structured messages, precise 15-second time synchronization, and robust error correction.

Cycles and Sequences

FT8 operates in 15-second cycles. Every communication cycle is strictly timed, starting exactly at 00, 15, 30, and 45 seconds of every minute. For this reason, your device's clock must be accurately synchronized to UTC time.

There are two sequences within the protocol:

Stations generally alternate between transmitting and receiving. A station transmitting in Sequence 0 will listen for a response in Sequence 1, and vice versa. Within each 15-second cycle, the message is transmitted in a window between approximately +0.5s and +13s. This leaves time at the end of the cycle for decoding and at the beginning for preparing the next transmission.

Signal Characteristics

Each FT8 message is transmitted as a sequence of tones with slight frequency variations (sometimes described as "wiggliness"). An FT8 signal is very narrow, occupying only about 50Hz of bandwidth. This efficiency allows dozens of simultaneous conversations to fit within a single 3kHz radio band.

The 6 Stages of a QSO

A standard FT8 contact typically moves through six stages. Here is an example of an exchange between HB9IPH and XX1XXX:

  1. 1/6 CQ: A station looks for anyone to talk to.
    Example: CQ HB9IPH JN47
    Note: JN47 is a Maidenhead grid locator, which indicates the station's approximate geographic location. There may also be a CQ modifier, which is a note for other operators (e.g., CQ SOTA HB9IPH for the Summits On The Air program, or CQ US HB9IPH when trying to contact someone in the US). Both the modifier and location might not fit in the same message; in such cases, the location is omitted. If the callsign is very long, it is possible that neither the location nor the modifier will fit in the CQ!
  2. 2/6 CALL: Another station responds to the CQ.
    Example: HB9IPH XX1XXX JO21
    Note: The responder also shares their location (JO21), which may be omitted if the callsigns are too long to fit everything.
  3. 3/6 RPT: The first station sends a signal report.
    Example: XX1XXX HB9IPH -10
    Note: The signal report (e.g., -10) indicates the signal strength relative to the noise floor in dB.
  4. 4/6 RRPT: The second station acknowledges the report and sends their own.
    Example: HB9IPH XX1XXX R-12
    Note: The "R" prefix confirms the previous report was received, followed by the signal report for the first station.
  5. 5/6 RR73: The first station confirms everything and sends a "Roger-Roger 73".
    Example: XX1XXX HB9IPH RR73
  6. 6/6 73: The second station sends a final "73" to close the contact.
    Example: HB9IPH XX1XXX 73

Because of the Two Generals' Problem, it is theoretically impossible to know for certain that the other station received your last communication unless they confirm so. However, then you would need to confirm their confirmation, and they would need to confirm that, and so on. The FT8 digital mode mitigates this by having structured stages: a QSO can technically be considered complete after stage 4/6 (when both signal reports have been exchanged). In practice, to ensure both stations agree that the exchange happened, a QSO is logged when a station has received an RR73 and has sent out a 73. Effectively, either transmitting an RR73 or a 73 triggers the logging of a QSO.

Note that stations may also call other stations even if they haven't transmitted a CQ first. For example, stations in rare locations may have a "pile-up" of many stations calling them simultaneously; in such cases, the rare station may simply move from one QSO to the next without needing to invite new callers with a CQ.

Some stations may use RRR instead of RR73 in stage 5. In that case, the contact requires an extra exchange: the second station sends 73, and then the first station sends 73 again to finish.

FT8 also supports free text messages (up to 13 characters), but qFT8 does not currently support sending these custom messages.

Protocol Limitations and Fallbacks

FT8 messages are highly compressed into 77 bits. Sometimes, complex information (like long, non-standard callsigns) does not fit in the standard message format.

FT4

FT4 is a streamlined digital mode designed specifically for amateur radio contesting, where rapid contact turnover is vital:

FT2

FT2 is designed for ultra-high-speed exchanges under favorable signal conditions, VHF/UHF meteor scatter bursts, and high-rate contesting:

JS8

JS8 (Jordan Sherer design, 8-GFSK) is created for conversational ragchewing, keyboard-to-keyboard chat, and ad-hoc networking rather than structured contest exchanges:

WSPR

WSPR (Weak Signal Propagation Reporter) is designed exclusively for probing radio propagation paths and automated beaconing rather than two-way conversational QSOs:

LQ8

LQ8 is an advanced weak-signal digital mode developed by Luis Quesada (HB9IPH), the author and creator of qFT8:

For more information, specifications, and tools, visit https://lq8.org, the portal for the LQ modes.

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qFT8 User Interface

The qFT8 app is split in three parts:

qFT8 Camera qFT8 Overview
  1. The bottom bar: Always visible, to oversee and control transmission and to control qFT8.
  2. The spectrogram: Always visible, to see decoded messages, see UTC time live and tuned frequency, and control transmission frequency offset.
  3. The tab area: Shows one out of four tabs (Stations, Log, World Map, and Settings). Which one is shown here can be controlled with the buttons at the right-most part of the bottom bar.

The following sections describe all these components in detail.

The Bottom bar

The bottom bar shows important information: the transmission armed/disarmed state, whether qFT8 is transmitting, the transmission power, the Standing Wave Ratio (SWR), the message being transmitted, the current and selected sequence, the band selector, and the buttons to navigate the different tabs.

qFT8 Camera qFT8 Bottom bar

These are the components of the bottom bar in detail:

  1. The cycle progress bar: The yellow bar starts at 0s within the cycle (left-most) and ends at 15s within the cycle (right-most).
  2. The Tx trigger marker: The red dot at the left part of the bar indicates the Tx trigger time. If Tx is ON (see item #4) and the current sequence is the selected sequence (see item #6) transmission starts at this point.
  3. The decoding time marker: The white dot at the right part of the bar indicates the decoding time, that is, when messages are decoded from signals received and subsequently processed.
  4. The TX button: Can be disarmed (OFF) or armed (ON). It also shows when transmission is happening, and the transmit power and SWR. In QMX firmwares above 1_04, this button will show "HOLD: TUNE". Holding the button will enable tuning mode and report on SWR live.
  5. The message selector: It shows the message selected to be sent or being sent (if that is the case, highlighted in yellow). In AUTO mode, it is managed automatically. In CALL mode it is also managed automatically by default, but it can be tapped on to select the next message to send manually.
  6. The sequence selector: The yellow line on top of the buttons show the current sequence (0 or 1). Tapping on 0 or 1 selects that sequence for outgoing transmissions.
  7. The mode selector: It changes the transmission mode used (e.g. FT8, FT4, FT2, LQ8, JS8, or WSPR).
  8. The band selector: When a transceiver is connected, it changes the band in the transceiver.
  9. The Stations tab button: Opens the tab that lists all the stations you've heard or can communicate with.
  10. The Log tab button: Opens the tab that lists all the QSO you've made. This button will be marked with a yellow dot if you have QSOs that aren't uploaded to QRZ.
  11. The World Map tab button: Opens the tab that displays the interactive global world map.
  12. The Settings tab button: Opens the tab to configure qFT8.
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The Spectrogram

The spectrogram shows a peak view, and the waterfall with incoming signals and messages, outgoing signals and messages, markers for the change of sequence annotated with UTC time and time to decode, and the selected offset frequency for transmission.

qFT8 Camera qFT8 Spectrogram

These are the components of the spectrogram in detail:

  1. Waterfall view: Displays the recent history of received signals over time. Tapping in that view will change the selected frequency offset.
  2. Real-time peaks: Show the instantaneous strength of signals across the frequency range. Tapping in that view will open a dialog to input the precise selected frequency offset.
  3. Sequence separators: These red horizontal lines act as visual separators of cycles, and are annotated with UTC time and time spent decoding.
  4. Selected frequency offset: This vertical yellow overlay on the spectrogram indicates the currently selected frequency offset for transmission.
  5. Incoming messages, shown color-coded:
    • Green: CQ messages.
    • Cyan: Messages between other stations.
    • Yellow: Your transmitted messages.
    • Orange: Incoming messages directed to you.
  6. Current UTC time and sequence: Displayed at the top of the waterfall.
  7. Tuned frequency and band: Frequency and band the transceiver is currently tuned to.
  8. Frequency axis: Shows the frequency scale in Hz within the selected band.
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The Stations tab

The Stations tab is the command center for monitoring activity on the band and operating qFT8. It features filtering and automation controls at the top, followed by a list of active stations.

qFT8 Camera qFT8 Stations tab

These are the components of the Stations tab in detail:

  1. AUTO call mode button: Engaging "AUTO" will try to call the best station according to the criteria selected by the user.
  2. Manual CALL mode button: Engaging "CALL" for a station will insist on calling that station until achieving a QSO, then will fall back to "AUTO".
  3. Target: Sets the criteria for the AUTO mode:
    • Anyone: Any callsign that you don't have a QSO for yet.
    • Nearby: Prioritize nearest stations based on Maidenhead grid distance.
    • Far: Prioritize farthest stations based on Maidenhead grid distance.
    • Signal strength: Prioritize stations with the strongest signal (SNR).
    • Call CQ: Just calls CQ and replies to any station that calls your station.
    • POTA hunter: Prioritize Parks on the Air stations.
    • SOTA hunter: Prioritize Summits on the Air stations.
    • POTA + SOTA hunter: Prioritize both Parks on the Air and Summits on the Air stations, then stations that are neither, ordered by SNR.
    • DXCC: Prioritize new countries/entities.
    • Grid: Prioritize new Maidenhead grid squares.
    • ITU zone: Prioritize new ITU zones.
    • CQ zone: Prioritize new CQ zones.
    • I/C/D/G: Prioritize first ITU zone, then CQ zone, then DXCC, then Grid.
    In all cases, stations that meet the same criteria are sorted by signal strength. For example, Anyone will prioritize new callsigns first, but among them the strongest signals will be at the top of the list.
  4. Periodicity: How often to contact that target:
    • once: In a lifetime.
    • daily: Once per UTC date.
    • weekly: Once every 7 days rolling window.
    • monthly: Once every month rolling window.
    • yearly: Once every year rolling window.
  5. Qualifier: How those constraints apply:
    • per callsign
    • in different bands
    • in different modes
    • until zone confirmed
    • per band+until zone
    • per mode+until zone
    • in different bands or modes
    • per band/mode+until zone
  6. Spy mode: When enabled, qFT8 will also try to call stations you haven't heard call CQ yet (marked as DIRECT). This is useful to have more stations at reach and join pile-ups.
  7. Busy mode: When enabled, qFT8 will also try to call stations engaged in a QSO with someone else (marked as BUSY). This is useful to join a pile-up.
  8. + button: Manually call any arbitrary station by inputting their callsign.
  9. Station information: Displays detailed status for each decoded station.

Individual station entries consist of four information-rich rows:

The first row shows station details (left to right):

The second row shows communication status (left to right):

The third and fourth rows show message exchanges with that station, including UTC time, frequency offset, and the message text (prefixed with Rx: for received messages or Tx: for transmitted messages). Depending on the Stations display mode configured in Settings → Application → User interface (which defaults to Compact - Last Rx, with options for Compact - Alternating, Compact - Last Rx/Tx, and Expanded), station cards display either three rows or four rows with both Rx and Tx messages.

Key visual indicators to watch for:

Stations are automatically sorted by relevance. Changing your target criteria or constraints will immediately re-sort the list.

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The Log tab

The log tab shows achieved QSOs.

qFT8 Camera qFT8 Log tab

These are the components of the Log tab in detail:

  1. Callsign text filter: A filter for QSOs based on whether the callsign contains the text inputted.
  2. Status filter: A filter for QSOs that shows:
    • All: Shows all recorded QSOs.
    • Confirmed: Shows only QSOs that have been confirmed.
    • Not confirmed: Shows QSOs that are not yet confirmed.
    • Not uploaded: Shows QSOs that haven't been uploaded to QRZ.
    • Duplicated: Shows QSOs that QRZ recognizes as duplicates.
    • Rejected: Shows QSOs that were rejected by the other station in QRZ.
    • Wrong Callsign: Shows QSOs recorded with a callsign different from the one currently configured.
    • Non FT8/FT4: Shows QSOs recorded for a mode other than FT8 or FT4.
  3. Recent limit filter: A filter that shows only the most recent 100 QSOs with the given criteria.
  4. The list of QSOs: Displays the log entries with the following columns (from left to right):
    • QRZ: Indicates your history with this station:
      • ✗: No QSO records.
      • ✓: Logged locally / Pending upload.
      • ✓🕒: Uploaded to LoTW, awaiting confirmation.
      • ✓: Uploaded to QRZ.
      • ★: Confirmed on QRZ or LoTW (for QRZ-uploaded QSOs) or manually.
      • ⟳ / ♻️: Circular arrow: Reported as duplicate by QRZ (only shown when actual duplicate entries exist in the log; unique QSOs already on QRZ are automatically marked as uploaded with a green tick).
      • ❕: Station callsign mismatch, already uploaded.
      • ⚠️: Station callsign mismatch, not uploaded.
      • ⛔: Rejected status.
    • Callsign: The station's callsign.
    • DXCC: The country or entity this station's callsign belongs to.
    • Grid cell: The Maidenhead grid square this station is reporting.
    • CQ zone: The CQ zone this station's callsign belongs to.
    • ITU zone: The ITU zone this station's callsign belongs to.
    • Band: The band on which the station was last heard.

Key visual indicators to watch for:

Editing QSOs: Tapping on any QSO in the list will open a prompt that allows manually marking a QSO as confirmed/unconfirmed locally in qFT8, or deleting a QSO locally in qFT8. Note that these actions are only local and are not synced to QRZ. Deleting a QSO in the app is irreversible, unless you keep an exported copy of the log file or it was uploaded to QRZ.

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The World Map tab

The World Map tab displays a real-time, interactive global map showing station geography, decoded traffic, your QSO achievements, and solar propagation conditions.

qFT8 Camera qFT8 World Map tab

These are the components and features of the World Map tab in detail:

  1. Interactive Map Canvas & Controls:
    • Navigation: Drag to pan smoothly across the globe with horizontal wrapping across the antimeridian. Pinch with two fingers to zoom in and out.
    • Map Themes: Switch between four visual styles (Bright Future, Console, Earth, and Midnight Navy) from the top toolbar.
    • HUD Coordinates: Displays real-time geographic coordinates (latitude, longitude) and Maidenhead grid locator under your touch position.
  2. Left Toolbar (Overlay & Info Toggles):
    • INFO: Toggles the on-screen information overlay cards (time, solar terminator, subsolar position, and crosshair coordinates).
    • MSGs: Toggles direct message route overlays and markers: shown in Orange for received messages (addressed to your station) and Yellow for sent messages (transmitted from your station). Tapping the arrow midpoint opens the message text overlay.
    • QSOs: Toggles your recent session contact markers (Amber for logged, Emerald for confirmed).
    • Spot: Toggles live decoded traffic spots on the band heard by your station (Cyan for RX/CQ) and reverse spotters reporting your signal on PSKReporter / WSPRnet (Red diamonds).
    • SOTA: Toggles Summits On The Air summit references and active summit activators (⛰️).
    • POTA: Toggles Parks On The Air park references and active park activators (🌲).
    • Band: Shows band propagation from online reports and a blindspot around the user. This is updated in real time when switching band if there's internet connection.

    The SOTA, POTA, STATS, and Spot buttons may be blinking, this means it was not possible to download updates.

  3. Right Toolbar (Achievement & Boundary Layers):
    • STATS: Toggles the summary statistics panel showing total logged and confirmed counts for the active boundary layer.
    • DXCC: Displays country and territory boundaries color-coded by your log status (Green for logged/unconfirmed, Yellow for confirmed). Small island and micro-entities appear as visible markers.
    • GRID: Global Maidenhead grid squares (fields and 4-character squares) with achievement fills.
    • ITU: Overlays the 90 ITU radio zones with achievement fills.
    • CQ: Overlays the 40 CQ magazine WAZ zones with achievement fills.
  4. Entity Details Card & Quick CALL Action:

    Tapping on any station, spot, park, or summit opens an informative detail card displaying:

    • Callsign or reference name, DXCC entity, and park/summit title.
    • Decoded message text, frequency, band, and mode.
    • Signal strength (SNR) or signal report (RST).
    • Grid locator, distance (km / mi), bearing (°), and elapsed time.
    • CALL button: Instantly initiate contact with the station (automatically switching band and operating mode if necessary).
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The Settings tab

The settings tab allows configuration of qFT8.

qFT8 Camera qFT8 Settings tab

The settings tab is organized as follows:

Submenus and Options

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Automated operation (AUTO)

AUTO mode is the primary way to use qFT8. In this mode, the application automatically analyzes the decoded messages at the end of every cycle and selects the most relevant station to contact based on your target criteria.

How Target Selection Works

The Stations tab displays a list of active stations, sorted such that the most relevant candidates (based on your criteria) appear at the top. At the end of each decode cycle, qFT8 looks at this sorted list and attempts to call the first eligible station. If no eligible target is found, it will automatically start calling CQ to attract callers. qFT8 always replies to calls in AUTO mode.

Criteria and Filters

You can fine-tune the automation using the three dropdown menus at the top of the Stations tab:

Manual Override: You can always manually intervene by tapping the CALL button for a specific station. This enters CALL mode for that specific QSO. Once finished, qFT8 seamlessly drops back into AUTO mode.

Retry Mechanism

To prevent qFT8 from calling a non-responsive station indefinitely, qFT8 offers a built-in retry and ban system, enabled by default. You can configure these in the Settings tab under Retry Logic:

Example Optimized Setups

Here are some recommended combinations of criteria for common goals:

Goal Target Interval Condition
Maximize unique stations Anyone Once Per callsign or zone
Maximize unique stations per band Anyone Once In different bands
Maximize unique DXCC entities DXCC Once Per callsign or zone
Maximize unique DXCC per band DXCC Once In different bands
Maximize confirmed DXCC entities DXCC Once Until zone confirmed
Maximize confirmed DXCC per band DXCC Once Per band + Until zone
Collect unique Grids per band Grid Once Per band + Until zone
Work all Zones (CQ/ITU) I/C/D/G Once Until zone confirmed
Contest: Unique stations on different bands Anyone Once In different bands
Contest: Points for same station on different days Anyone Daily In different bands

Note that in all these cases, you may enable Spy and Busy to reach out to more stations and enter their pile-ups.

Note: If your callsign is not standard (e.g. with "/"-separated suffixes or prefixes, long callsigns, or other callsigns with numbers in rare positions), you probably want to set Target to Call CQ as your callsign will likely be sent out hashed and only stations who have seen you call CQ will be able to map the hash to your callsign. You may still call stations but they will only map the message to your callsign if they recently heard you call CQ.

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Manual operation (CALL)

While qFT8 is highly automated, you can take control at any time. Tapping the CALL button next to any station in the Stations tab will immediately enter CALL mode and attempt to establish a QSO with that specific station.

Once the QSO for the manual target is completed (successfully or not), qFT8 will automatically fallback to AUTO mode and resume your previous automated strategy (e.g., calling CQ).

Timing for Manual Operators

If you find that you'd like more time at the end of the cycle to make manual decisions, you can get yourself more margin by adjusting the FT8 Settings in the Settings tab:

Warning: Adjusting these values aggressively into the margins may make your messages much more difficult for other stations to decode, as you are reducing the effective time available for the actual FT8 signal within the sync window.

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ADIF Import/Export

qFT8 supports the standard ADIF (Amateur Data Interchange Format) for interoperability with other logging software, cloud services, and for manual backups.

Importing QSOs

The import feature allows you to bring records from other sources (like other logging programs or backups from other devices) into your local qFT8 log.

Exporting QSOs

Tapping EXPORT QSOs generates an ADIF 3.1.6 file and opens the system Share sheet, allowing you to save the log to your device or send it via email/messaging.

Note: For very large logs (over 100KB), qFT8 will display a warning as the deduplication and sorting process may take a few moments to complete on your mobile device.

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QRZ Integration

qFT8 offers deep integration with QRZ.com to keep your logbook automatically synchronized. Note that QRZ integration is a subscription service that requires a QRZ paid subscription (XML Logbook Data or higher). If you prefer a free alternative, consider using LoTW integration, which is provided at no charge by the ARRL.

How it Works

To enable QRZ integration, you need to provide your QRZ API Key in the settings tab. You can find your API Key on the official QRZ Logbook API page. Once entered and VALIDATED, you can enable "Upload QSOs to QRZ" for automatic background management.

Syncing Confirmations

The integration goes beyond just uploading. qFT8 also polls QRZ to see if your QSOs have been confirmed.

Pro Tip: You can see the sync progress in settings under "Oldest QSO synced for confirmation". There's no urgency in keeping this up to date, as qFT8 will take care of it over time.

Log Syncing Strategy

In the synchronization settings, you can choose how qFT8 determines if a QSO is "fully uploaded" via the "Consider a QSO uploaded when uploaded to:" option:

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Logbook of the World (LoTW) Integration

qFT8 provides a robust integration with the ARRL Logbook of the World (LoTW). Integrating with LoTW is highly recommended for confirming your contacts and earning awards like DXCC and WAS.

Setup Requirements

To fully enable LoTW features, including automatic uploads and confirmation checks, you need to provide four specific pieces of information in the settings tab:

Station Location Automation: Details such as ITU Zone, CQ Zone, and Station Name are automatically determined from your callsign. No manual configuration is required for these fields.

Features

Log Syncing Strategy

In the synchronization settings, you can choose how qFT8 determines if a QSO is "fully uploaded" via the "Consider a QSO uploaded when uploaded to:" option:

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Summits On The Air (SOTA)

qFT8 provides comprehensive, built-in tools for both SOTA (Summits On The Air) Chasers (Hunters) and Activators, complete with automated spot fetching, real-time reference tracking, achievement highlights, and dedicated ADIF export filters.

Live Summit Spot Auto-Fetching

When internet access is available, qFT8 automatically connects to the official SOTA API in the background (refreshing every 90 seconds) to fetch active summit activations worldwide.

Operating as a SOTA Chaser / Hunter

To hunt stations activating summits:

  1. In the Stations tab, set the target priority dropdown to SOTA hunter (or POTA + SOTA hunter).
  2. Visual Badges & Reference Column: Active SOTA stations (spotted online or transmitting CQ SOTA) are marked with a SOTA badge in Row 2. In addition, the DXCC column header switches to SOTA Reference, displaying the summit code directly.
  3. Worked vs. Needed Summit Highlights:
    • Unworked Summit: Marked with a vibrant purple SOTA badge and purple reference text, indicating a new summit to chase.
    • Already Worked Summit: Displayed in a subtle grey badge, allowing you to instantly distinguish fresh summits from those already in your log.
  4. AUTO Chasing: In AUTO mode, qFT8 automatically prioritizes calling unworked SOTA activators over regular CQers, ordering them by strongest signal strength (SNR).

Managing & Editing SOTA References in the Log

qFT8 offers dedicated tools to inspect and edit your SOTA chase history:

Operating as a SOTA Activator

To run a SOTA activation from a summit:

  1. Synchronize time: Ensure your device clock is accurate before heading into the field.
  2. Set your CQ Modifier: In the Settings tab, set CQ modifier to SOTA. Every CQ call will transmit CQ SOTA [Callsign].
  3. Configure AUTO Mode: In the Stations tab, set the target priority to Call CQ and engage AUTO mode.
  4. Start Activating: Enable TX. qFT8 will automatically call CQ and reply to incoming chasers in sequence.

Manual Overrides: If several chasers call you simultaneously and you wish to pick a specific station, tap CALL on their entry. Once that contact completes, qFT8 automatically returns to calling CQ.

Exporting your SOTA Logs (Chasers & Activators)

qFT8 allows generating tailored ADIF exports for both hunter submissions and activator logs:

  1. Go to Settings and tap ADIF File Export.
  2. For Chasers / Hunters:
    • Set Hunter criteria to Only SOTA contacts (summits) to export only QSOs where a summit reference was contacted (with <SOTA_REF> populated).
  3. For Activators:
    • Select Selected time range to match your activation start and end times.
    • In Event, choose SOTA and enter your activated summit code (e.g., HB/BE-001). qFT8 injects your reference into <MY_SOTA_REF> on every record.
  4. Summit-to-Summit (S2S): If you worked another activator while activating a summit, qFT8 includes both your activator summit (<MY_SOTA_REF>) and the contact's summit (<SOTA_REF>) in the exported file.
  5. Press EXPORT QSOs to share or save the standardized ADIF file.
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Parks On The Air (POTA)

qFT8 provides full, native integration with the POTA (Parks On The Air) program for both Hunters and Activators, featuring automatic spot retrieval, worked park tracking, reference editing, and flexible export options.

Live Park Spot Auto-Fetching

When connected to the internet, qFT8 automatically queries the official POTA API in the background (every 90 seconds) to retrieve all active park activations across the globe.

Operating as a POTA Hunter

To hunt stations activating parks:

  1. In the Stations tab, set the target priority dropdown to POTA hunter (or POTA + SOTA hunter).
  2. Visual Badges & Reference Column: Active POTA stations are tagged with a POTA badge in Row 2, and the DXCC header switches to POTA Reference to show the park code.
  3. Worked vs. Needed Park Highlights:
    • Unworked Park: Marked with a bright purple POTA badge and purple reference text, indicating a park you have not yet worked.
    • Already Worked Park: Displayed in a subtle grey badge, making it easy to prioritize unworked parks during busy band conditions.
  4. AUTO Chasing: In AUTO mode, qFT8 prioritizes unworked POTA activators over regular stations, ordering candidate targets by signal strength (SNR).

Managing & Editing POTA References in the Log

Inspect and maintain your park hunter logbook directly within the app:

Operating as a POTA Activator

To activate a park:

  1. Synchronize time: Ensure device clock accuracy before beginning your activation.
  2. Set your CQ Modifier: In the Settings tab, set CQ modifier to POTA to transmit CQ POTA [Callsign].
  3. Configure AUTO Mode: In the Stations tab, set target priority to Call CQ and engage AUTO mode.
  4. Start Activating: Enable TX. qFT8 will continuously call CQ and work incoming hunters automatically.

Manual Overrides: Tapping CALL on any queued station prioritizes that QSO before returning to AUTO CQ mode.

Exporting your POTA Logs (Hunters & Activators)

Generate standardized ADIF files ready for upload to pota.app:

  1. Go to Settings and tap ADIF File Export.
  2. For Hunters:
    • Set Hunter criteria to Only POTA contacts (parks) to export only QSOs where a park was hunted (with <POTA_REF> populated).
  3. For Activators:
    • Select Selected time range to match your activation window.
    • In Event, select POTA and enter your park reference (e.g., K-1234). qFT8 automatically populates <MY_SIG>POTA, <MY_SIG_INFO>, and <MY_POTA_REF> across all exported records.
  4. Park-to-Park (P2P) & Park-to-Summit (P2S): When hunting other parks or summits during your activation, both your activator park (<MY_POTA_REF>) and the remote contact's reference (<POTA_REF> / <SOTA_REF>) are exported simultaneously.
  5. Press EXPORT QSOs to share or save your log file.
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JS8 Chat

When operating in JS8 mode, qFT8 provides a conversational free-text chat interface alongside traditional FT8/FT4 QSO operations. JS8 enables robust, weak-signal keyboard-to-keyboard messaging at multiple configurable speeds (Slow 30s, Normal 15s, Fast 10s, and Turbo 6s slots).

qFT8 Camera qFT8 JS8 Chat

Channel Types & Routing

The chat panel on the right-hand side organizes incoming and outgoing traffic into separate channel tabs:

Over-the-Air Transmission (Not Private): All JS8 messages are transmitted in the clear as standard amateur radio digital signals. Direct station chats route conversation history into a dedicated tab for convenience, but they are not encrypted or private and can be received by any station monitoring the frequency.

Composing & Sending Messages

  1. Select a Target: In the right-hand panel, tap a channel tab ([GLOBAL], @CQ, @ALLCALL, a group, or a specific station callsign).
  2. Enter Message: Type your text in the input box at the bottom (supports full standard ASCII text up to 100 characters).
  3. Send: Tap the Send button.

Tapping on Messages (Quick Chat & Details)

Tapping on any message in the chat log opens a detail dialog showing the full UTC timestamp, audio frequency, SNR, Maidenhead grid, and message content:

Multi-Chunk Message Streaming

If your message is longer than what can fit inside a single JS8 transmission frame:

Managing Channels (Long-Press Actions)

Long-pressing (holding) on any station callsign tab or group channel tab in the right-hand panel opens a context menu with management options:

Automated Query Replies (AUTO Mode)

When the AUTO button is enabled, qFT8 automatically responds to incoming directed queries sent by other stations (such as SNR?, HW CPY?, GRID?, INFO?, STATUS?, and HEARING?) as well as heartbeat messages (@HB HEARTBEAT).

For example, if another station transmits YOURCALL SNR? or YOURCALL HW CPY?, qFT8 will automatically enqueue and transmit your signal report response (e.g. SNR -08) without requiring manual intervention. Similarly, when receiving a heartbeat transmission (@HB HEARTBEAT), qFT8 will automatically enqueue a heartbeat acknowledgment (HEARTBEAT SNR -08) to report reception back to the transmitting station.

Directed Queries & The Request Button

The Request button allows you to quickly send standard directed queries to the currently selected target station or group without having to type the command syntax manually:

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WSPR Mode

WSPR (Weak Signal Propagation Reporter) is a specialized digital protocol designed for probing radio propagation paths using very low power transmissions. WSPR signals use narrow 4-FSK modulation with robust convolutional coding and sequential Fano decoding, capable of decoding signals well below the noise floor down to −28 dB SNR.

2-Minute Cycles & Timing

WSPR transmissions take place in synchronized 2-minute UTC slots (transmitting for 110.6 seconds with 162 tone symbols). Transmissions always start exactly one second into even UTC minutes (:00, :02, :04, :06...). The spectrogram vertical scrolling automatically adapts to a smooth, slow scroll rate matching the 120-second cycle length.

Single-Pane Activity View

Because WSPR is a beaconing and propagation reporting protocol rather than a two-way conversational mode, qFT8 provides a streamlined, full-width single-pane activity log without QSO log splits:

  • Callsign: Station callsign.
  • DXCC Entity: Automatically resolved country / DXCC entity name (with flexible width).
  • Grid Locator: 4-character Maidenhead locator (e.g. JN45).
  • SNR: Received signal-to-noise ratio in dB.
  • Power Level: Transmit power reported by the station in dBm (e.g. 37 dBm).
  • Date & UTC Time: Timestamp of the transmission slot in UTC formatted as yyMMdd HH:mm.

Automated Beaconing & Tx Percentage

In the top header of the WSPR Activity screen:

  • BEACON Toggle: Arm or disarm automated beacon transmissions. When armed (highlighted in bright green), qFT8 automatically schedules beacon transmissions at deterministic intervals based on your configured Tx Percentage.
  • Tx % Selector: Configure the deterministic transmission duty cycle based on time elapsed since your last transmission (0% [Rx Only], 10%, 20%, 25%, 33%, 50%, or 100% Continuous). For example, 20% transmits deterministically every 10 minutes from your last transmission (50% = every 4 min, 33% = every 6 min, 25% = every 8 min, 10% = every 20 min, 100% = every 2-minute cycle continuously).
  • Send Button: Queue an immediate manual transmission for the upcoming 2-minute cycle boundary. After transmitting, automated deterministic beacon scheduling continues from that cycle.

WSPRnet & PSKReporter Spot Uploads

qFT8 can automatically upload received spots to the global WSPRnet database and PSKReporter:

  • Download spots from WSPRnet: Enabled by default, pulls real-time spots for your callsign and band to display on the World Map.
  • Upload reports to WSPRnet: When enabled under Settings → WSPRnet, received spots are batched and uploaded to WSPRnet with 15-minute deduplication and rate limiting.
  • Open WSPRnet in Browser: Directly opens the WSPRnet database filtered for your station's callsign.

Standalone ADIF Export

Tap the EXPORT button at the top right of the WSPR activity panel to export all spots recorded during the current session into standard ADIF format (.adi) for propagation study and record keeping.

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Remote Control Web Server

qFT8 includes an embedded HTTP server that allows you to monitor and control the application from any web browser on your network. This is particularly useful for remote operation or as a secondary display.

This is how the Spectrogram/Stations view looks like in the remote control web server:

Remote Control Web Server Stations

It allows operating with the AUTO button, criteria dropdown, + button to directly add callsigns, and the list of stations with CALL buttons to manually call them.

And this is how the Spectrogram/Log view looks like:

Remote Control Web Server Log

This view shows the most recent log entries.

Network & Connectivity

The server opens a specific TCP port (default 13497) on your phone. To access it, your devices must be able to "see" each other on the network:

  • Local Network: Both the qFT8 phone and your control device (computer, tablet, or another phone) must be on the same Wi-Fi network.
  • Router Settings: Some routers have a feature called AP Isolation (or Client Isolation) enabled by default. This must be disabled for devices to communicate with each other.
  • Mobile Hotspot Scenario: If you are in the field, you can open a Wi-Fi hotspot on one phone (with internet) and connect the qFT8 phone to that Wi-Fi network. After connecting, close and reopen the web server in qFT8 settings; the IP address shown will then be accessible from the hotspot-providing phone.
  • Internet Access: Accessing the server from outside your home (over the internet) requires Port Forwarding in your router settings (mapping the internal IP and port to an external one). Note that this generally will not work over 5G/LTE connections due to carrier NAT restrictions.

Access Levels

You can configure the remote security level in the settings pane:

  • Read only: Allows viewing the live spectrogram, active stations, and the QSO log. No actions can be performed.
  • Read + Stop TX: Primarily a safety mode. Allows viewing all data and permits disarming the transmitter (stopping TX) in case of an emergency, but does not allow starting TX or changing settings.
  • Full control: Grants complete authority over the application, enabling all interactive features.

Security Note: Anyone with access to your network, IP address, and port will have the level of control you have configured. If set to Full control, they could potentially start transmitting using your station.

Capabilities

In Full control mode, the web interface offers nearly everything the app UI does:

  • Operation Modes: Toggle between AUTO and manual CALL modes.
  • Strategy: Change the AUTO criteria (Anyone, DXCC, Grid, etc.) and search constraints.
  • Transmission: Manually start/stop TX, choose specific TX messages, and change the FT8 sequence (0/1).
  • Frequency & Band: Tap the web spectrogram to move your frequency offset or change the active radio band.

Note: The web UI is designed to remain responsive even if the physical phone's screen becomes sluggish due to RF interference, providing a reliable fallback for control.

Note: The web server will function when the screen is off if the settings to run in background are enabled (the default is to keep running in the background when qFT8 is connected to a transceiver).

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Troubleshooting

Android device doesn't recognize the transceiver or it gets disconnected

This is almost always a hardware connectivity or radio interference issue. USB connections are sensitive to vibration, cable quality, and fluff phone raccoons dwelling in the USB port. Another common cause is that USB OTG may be disabled by default in your Android device (in particular if you are able to receive signal from qFT8 but not transmit and CAT commands don't work even when the device is fully supported, shown in the device dropdown, autorecognized in AUTO mode, etc., this is very likely the cause).

Try:

  • Enabling USB OTG in your Android device settings (on some devices, OTG is disabled by default and may be located under advanced, system, or additional settings).
  • Using a high-quality, short USB cable (using a shorter cable can significantly help), and ensure the port on your phone is clean and the connection is tight.
  • If the issues occur specifically while transmitting, it could be caused by radio interference. Adding chokes or ferrites to the USB cable could help. You can also try transmitting in a different band, as some devices are only sensitive to interference in certain bands.

Instead of receiving signal from the transceiver, qFT8 is getting audio from the microphone

This indicates that the phone is using its internal microphone because it doesn't recognize the transceiver as an external audio source. The most common causes are:

  • The USB cable is not rated for data (charge-only cable).
  • The USB adapter (OTG) is faulty or incompatible.
  • The cable is plugged in the wrong direction (some cables are directional).

Try: Using a different USB cable, a different adapter, or flipping the cable connections.

Not receiving any signal at all; the waterfall is pitch black

If the waterfall remains entirely black both when the transceiver is connected or disconnected, qFT8 likely lacks the necessary permissions to access audio.

Try: Go to your phone's Settings > Apps > qFT8 > Permissions and ensure that Microphone (or Audio recording) is allowed while using qFT8. Alternatively, fully uninstall and reinstall qFT8 and accept all permission prompts on the first launch.

Signals are visible, but no messages are decoded

If you see vertical "wiggly lines" in the waterfall (FT8 signals) but no text appears in the Stations tab, perhaps your clock is not synchronized.

Try:

  • Ensure you have internet access and reopen the app to trigger an NTP sync.
  • If no internet is available, try a GPS sync.
  • If that also doesn't work but message tones are visible in the spectrogram, trigger an emergency time sync from the messages, from the time and location settings menu.
  • Ensure your radio is actually receiving signals from the air.

If no wiggly stripes appear at all in the waterfall, perhaps the band is closed or your antenna is disconnected/untuned.

Messages are decoded too late

The phone processor may be too slow to decode messages on time.

Try: Make sure you switch to Fast decode in the settings, and feel free to move decoding time earlier (e.g. to 13000ms) to create more margin for decoding, at the expense of potentially missing some late messages every cycle.

Error "SWR exceeded threshold — transmission stopped" in the QMX transceiver

If qFT8 shows 0W while transmitting, there are several likely causes:

1. SWR Protection

If the QMX LCD display shows an "S" after the frequency, it means SWR protection kicked in. This means your antenna is not properly tuned for the current band, and the QMX has stopped transmitting to protect its circuitry.

Additionally, qFT8 has its own configurable SWR threshold setting in the app settings. When measured SWR exceeds this threshold, qFT8 will automatically stop transmission to protect your equipment.

  • Firmware 1_04_004+: qFT8 automatically resets SWR protection at the end of the cycle.
  • Firmware 1_03_000+: You can set "SWR Protection reset options" to Timer or TX->RX in the QMX menu. This allows qFT8 to continue operating without you having to touch the transceiver physically.
  • Legacy Firmware: On QMX firmware older than 1_03_000, you must manually reset the transceiver (off/on) or enter and leave the TUNE menu on the QMX to clear the error.

Note: qFT8 waits 1 second after the start of transmission before checking for 0W to avoid false positives while the QMX ramps up. If the QMX recovers and power rises above 1W, the problem indicator clears automatically.

2. Firmware doesn't support power measurement

If the QMX does not show that SWR protection is engaged, and it shows that transmission is happening properly, it may be that the firmware is old and does not support power measurement. Devices like the QDX also do not support power measurement. qFT8 does not know how to interpret 0W and it gets confused.

Try: If your QMX firmware is old, update it. If you are using a QDX, there is no way around this.

3. Audio signal not reaching the QMX

If the QMX does not show the "S" icon after the frequency, then it is likely that the transceiver is simply not receiving a suitable audio signal from the phone. The volume may be too low (not enough signal) or too high (clipping/distortion causes the QMX to reject the signal).

Try: Check the signal indicator on your QMX. A single dot means no audio, two dots mean there's audio but it's not loud enough. Go to the FT8 Settings section and adjust the "Set system volume to [X] when transmitting" setting to different values (e.g. 70%, 80%, 90%) to find the right level for your device.

4. SWR is low during tuner but SWR protection kicks in

This seems like SWR is spiking or peaking at high power for some instants during actual transmission, which triggers SWR protection. This is an indicator of a finnicky antenna (e.g. magloops), a bad cable, a bad connection, or an issue in the setup.

Try: adding common-mode current chokes (such as ferrite beads) should decrease common-mode current.

What is the qFT8 Android notification?

This notification allows qFT8 to continue processing audio and managing QSOs when you minimize the app or turn off the screen.

  • By default, it triggers automatically when a transceiver is plugged in.
  • You can disable this in qFT8 settings, but qFT8 will stop working in the background.
  • You can press STOP in the notification to fully close qFT8.

qFT8 stops working when the screen is off

Some Android manufacturers implement very aggressive battery optimizations that may kill background apps even if you granted the initial permissions.

Double check that you granted the permissions: Go to your phone's Settings > Apps > qFT8 > Battery and select "Unrestricted" (or "Don't optimize").

Buttons act weird or the screen is unresponsive during TX

This is caused by RF Interference (RFI). If your antenna is close to the phone or the cable is poorly shielded, the radio energy can interfere with the touch digitizer.

  • Tip: Use a shielded USB cable or clip a ferrite bead onto the cable.

qFT8 looks different than the screenshots in this manual

The app's user interface is occasionally updated, so some minor visual elements may have changed since the screenshots were taken. However, if significant parts of the UI are completely missing or the colors look heavily altered (e.g. the yellow progress bar, the sequence selectors, etc.), your phone's system dark mode may be incorrectly overriding and messing up the application's color palette.

Try: If your system's dark mode is causing issues, you can try temporarily disabling it or adding qFT8 to its exclusion list to restore the correct design.

qFT8 says "NO RADIO" even though transceiver is connected

The issue is likely that you didn't grant the permissions to connect qFT8 to the transceiver. Sometimes this happens because you tap somewhere out of the permission dialog and the dialog closes.

Try: Disconnect and reconnect the transceiver, this should trigger the prompt again. For comfort, mark the option "Always open qFT8 when transceiver is connected" so you never hit this issue again.

qFT8 shows distance in miles and I want it in kilometers (or vice versa)

This comes from the operating system locale (i.e. language selection).

Try: Switching that configuration to the right country (e.g. English (United States) for miles, English (United Kingdom) for kilometers) will fix it.

qFT8 shows low transmission power (e.g. 0.1W) when transmitting at >10W in QMX

This is a known bug in the QMX firmware (up to at least 1.03.000). If you are using the 2x4 mods (e.g. in a QMX+) and your transmission power exceeds 9.9W, the radio's formatting wraps around. For example, 10.1W is reported by the transceiver to the app as 0.1W over the secondary CAT protocol.

Try: There is no workaround inside qFT8, as the app is directly displaying the value it receives. You can safely ignore this display error or reduce your power below 10W to keep the readings accurate until this bug is patched in the transceiver firmware.

Cannot export ADIF logs to the local storage using Share

The default Share method relies on the native Android share mechanism to export logs. Sometimes, your device's built-in file sharing menu does not offer a direct option to save to your local filesystem.

Try: Change the export Method to Local save in the settings. This uses the Android file picker to directly save the file to your local storage without relying on the sharing menu.

qFT8 fails to decode some messages

Try: Enable deep decode in the settings. Deep decode does recursive decoding and is able to decode more messages when the band is busy, at the expense of extra processing power. Keep an eye on the spectrogram: if deep decode time is too high in your device (e.g. greater than 1 second) and the app is not able to make decisions on time, disable deep decode.

qFT8 hangs or behaves strangely

If this happens only during transmission, it is likely extreme RFI as mentioned above. If it happens at other times, please scroll to the bottom of the Settings tab and use the "Email me to report issues and bugs" link.

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Copyright © 2026, Luis Quesada Torres (HB9IPH). All rights reserved.

Includes parts from usb-serial-for-android (Copyright © 2011-2020 Google Inc., Mike Wakerly, Andreas Butti, Kai Morich, BSD-3-Clause), Roboto (Copyright © 2015 Google Inc. / Christian Robertson, Apache-2.0), Roboto Mono (Copyright © 2015 Google / The Roboto Mono Project Authors, OFL-1.1), Natural Earth (Public Domain), hamradio-zones-geojson (Copyright © 2024 HB9HIL, HA8TKS, MIT license), Big CTY (Copyright © Jim Reisert AD1C), and Eclipse Temurin (OpenJDK) Java Runtime (Copyright © Oracle and/or its affiliates and other contributors, GPLv2 with the Classpath Exception). None of these third-party authors or projects endorse or are affiliated with qFT8.

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