Transmit controls change shared radio state. Before keying, confirm the transmitting slice, microphone route, antenna, intended drive, and current TX holder. A control can be visible but disabled because the radio is receive-only, the Core has no transmit permission, a TX inhibit or interlock is active, another device owns TX, the mode is not supported for TX, or the Core is applying a station change. Read the control's tooltip or status reason and resolve that condition before trying again. This build does not provide CW transmit for CWL/CWU, FM transmit, or DRM transmit; SPEC cannot transmit. For profile editing and detailed speech processing, see Voice processing and profiles; for antenna and PA calibration, see Radio hardware and calibration.
Begin with a connected, transmit-capable radio and the intended slice selected. Open File > Settings… > Audio > TX Input. Mic Source offers PC Mic, Radio Mic, and VAX TX (virtual device). The local desktop chooses the radio's source; a remote desktop chooses its authenticated session's input and waits for the Core's accepted readback. Choose PC Mic for a microphone captured by this computer, Radio Mic for a radio's supported hardware input, or VAX TX when an external digital program supplies audio through the virtual device. Radio Mic controls vary by radio family, and unavailable rows remain gated with their displayed reason.
For PC Mic, open File > Settings… > Audio > TX Input. In PC Mic, choose the Backend and Device that contain the intended input. Use Buffer to adjust capture buffering only when the current route reports dropouts or unacceptable delay; its label shows samples and approximate milliseconds at 48 kHz. A smaller buffer reduces latency but may be less tolerant of a busy computer or backend. Check Test Mic and its VU indicator. If the stream is unavailable, open Audio > Devices, confirm the selected capture device under TX Input (Microphone) and the operating system's microphone permission, then press Retry microphone and test again. Adjust Mic Gain only when the meter shows a level mismatch; its range depends on the connected board. These controls test local capture without putting RF on the air. The microphone group and selected source have separate Core permission gates.
When Radio Mic is selected, use only the group shown for the connected board. Radio Mic (Hermes / Atlas) offers Mic In or Line In, +20 dB Mic Boost, and Line In Gain. Radio Mic (Orion-MkII) offers Mic Tip-Ring (Tip is Mic), Mic Bias, Mic PTT Disabled, and +20 dB Mic Boost. Radio Mic (Saturn G2) offers 3.5 mm Jack or XLR plus its Mic PTT Disabled, Mic Bias, and +20 dB Mic Boost controls. Set these to match the microphone wiring and electrical requirements; Mic Bias or boost can be inappropriate for a particular microphone. Verify the selected source and test on an authorized, low-drive transmission. A control disabled with a reason is not configurable on this Core or radio. In the candidate, Hermes Lite 2 offers Radio Mic with an explicit audio-add-on requirement. A stock HL2 sends no microphone audio; selecting the row does not detect or supply the add-on. Verify the actual compatible audio hardware before using that input.
In a supported remote desktop session, Radio Mic selects the physical microphone at the Core's radio. Wait for the source-selection status to settle; the page explicitly reports that no computer microphone stream is used. Its VOX route is unavailable from this remote window, and program-audio keying requires PC/VAX input instead. Older Cores can refuse the radio-mic selection. PC Mic uses this computer's capture; VAX TX uses its digital application input. Changing that local device does not change the radio jack.
The Phone / CW applet is a quick radio-side control surface. Its source buttons include supported PC, MIC, BAL, and LINE radio inputs. Select a source there only after confirming what is physically connected to that input. ACC is unbuilt and must not be used as a source. Phone/CW MON is also unbuilt; the separate MON control in the TX applet is the implemented transmit-audio monitor. The Phone/CW page is not a CW keyer or FM transmit panel.
Use the evidence in order, and keep the transmitter unkeyed for the local check:
Select the intended mic/TX profile in the TX applet's profile selector. Its profile controls are described in Voice processing and profiles. Profile editing is reached from File > Profiles > TX Profiles…, File > Profiles > Mic Profiles…, or File > Settings… > Audio > TX Profile. Both File profile entries open the same profile editor. The File menu's Import… and Export… entries instead open Diagnostics configuration backup/restore; they do not transfer individual TX profiles. A profile is also separate from radio-authoritative power, antenna state and transmit ownership.
In the TX applet, select the letter for the slice that should transmit, or right-click its VFO flag and choose Make this the TX slice. The flag action is permission-gated and unavailable for a receiver you only listen to. Confirm the resulting TX selection, frequency and mode on the VFO flag. The TX slice determines the transmit frequency/mode; the active RX slice is not automatically the TX slice. If another connected device holds TX, the applet identifies the holder and displays Take transmit. Press it to request the handoff, wait for the owner/readback to change, then reselect the intended TX slice. Do not repeatedly press MOX or TUNE while the Core reports another holder.
The reviewed phone build has no general Take transmit action. When the phone already holds TX, its TX badge can select the desired slice. A first human PTT on an eligible original owned slice can acquire an unheld transmitter after all ordinary RF/microphone checks. A taken-only slice or another device's holder can refuse that request; use the supported starting states in phone transmit preparation and keep receiver handoffs receive-only when no valid TX route is offered. The physical headset, Bluetooth, Action-button, and locked-screen PTT button choices in the phone setup are disabled shell controls. They do not make those physical buttons supported transmit routes. The phone's on-screen PTT path and its timeout are covered in the mobile chapters.
Take transmit can ask for confirmation naming the current device and the impact, including unkeying an on-air holder. Read that question and coordinate before confirming; wait for the accepted holder and TX slice. A changed holder or a holder that keyed after the first question can require another confirmation. The Core rechecks this session's transmit permission when applying the answer. Unkeying does not release ownership, and a refused take does not grant it.
Wait for the radio to settle fully in receive before another key or TX-slice move. The TX-to-RX tail or a frozen TX flag can produce an on-air refusal even when MOX has just cleared. On a hosting desktop, a radio footswitch/mic PTT keeps a flag on its own chosen slice (including a split TX slice) or an unowned slice. If the flag belongs to another device, an admitted radio-side PTT can move it to the hosting desktop's active slice. With a headless Core, radio-side PTT uses the flag's slice. Check the actual flag, holder and station wiring before relying on a physical PTT; a shared receiver view does not determine that target.
The TX applet's RF Power slider sets transmit drive. Tune Pwr stores the transmit band's tune drive. TUNE and 2-Tone each have a selectable drive source; check that source before keying. Their numerical labels are relative drive values unless a supported PA profile is configured with MAX watts @ 100%. Do not read either slider as watts by default. Hardware-specific scales differ; Hermes Lite 2 uses fewer drive steps and displays its own dB values. The Power page can expose radio/PA limits and controls according to hardware and permissions. Use the station's verified output meter, not the slider number, to establish RF power.
Before a first transmission, move RF and Tune drive to a conservative setting appropriate to the radio, amplifier, and load. Watch forward power and SWR meters during a brief authorized test. A meter with no reading can mean no transmit, a radio/PA without that telemetry, an unavailable feedback path, or an incorrect output route; it is not proof of zero RF. Keep the Tune setting conservative because TUNE produces a continuous single-tone carrier while active.
For a PA-scaled watts workflow, use File > Settings… > PA > PA Gain only when a supported PA profile is offered. Follow that page's bands, gain and maximum-watts controls and the displayed calibration readiness. The profile's maximum-watts setting is what permits a drive control to be interpreted on that scale; it is not a power measurement by itself. The hardware chapter covers Watt Meter, PA Values, and calibration controls. If no supported profile is active, keep describing RF Power and Tune Pwr as drive and use an independent station meter for actual watts.
Open File > Settings… > Transmit > Power while receiving. In Tune, choose the Drive Source intentionally:
| Choice | Value used for TUNE |
|---|---|
| Use Drive Slider | The current RF Power drive. |
| Use Tune Slider | The saved Tune Pwr for the transmit band. |
| Use Fixed Drive | Fixed Tune Power on this page, using the radio's displayed scale. |
Moving the TX applet's RF Power slider selects Use Drive Slider; moving Tune Pwr selects Use Tune Slider. The last change can therefore replace a previous source selection. Recheck the Tune group's radio button and value before a test, especially after changing ordinary transmit drive. A remote window uses the Core's permitted tune settings and readbacks; a refused edit must be resolved before assuming the new drive is in effect. The separate TX TUN Meter selector is not a working meter-routing control in this build. Use the implemented meter readouts rather than relying on that selection.
The Power group also has Max Power (W):, which writes the same transmit drive setting as RF Power. Its caption does not establish measured watts. ATT on TX enables transmit-time receive/feedback attenuation, and ATT on TX (dB): supplies its value. The allowed minimum is radio-specific; the page obtains the connected radio's range. Force ATT on Tx to 31 when PS-A is off applies the offered forced-attenuation policy. These are shared radio settings, not microphone gain or a reduction in PA output drive.
Record the present attenuation and policy before editing, then set only values established for the connected receiver/feedback path. Confirm the readback and PureSignal feedback indication during the controlled test. With automatic feedback attenuation active, a changing attenuation readback can be the controller's adjustment. If feedback worsens, unkey and inspect the path and policy; raising RF drive is not the remedy for a receiver attenuation problem.
2-Tone starts a transmitted test signal. Configure it while receiving in File > Settings… > Test > Two-Tone IMD. This page edits shared transmitter settings; in a remote window a Core/version/permission refusal can prevent an edit. These controls do not themselves start the generator.
| Control | Meaning and interaction |
|---|---|
| Freq #1, Freq #2 | Tone frequencies in Hz, each −20,000 to +20,000. Choose frequencies appropriate to the intended mode and measurement bandwidth. |
| Defaults | Sets only the two frequencies to 700 and 1900 Hz. Other test settings remain as shown. |
| Stealth | Sets only the frequencies to 70 and 190 Hz. It does not make a transmission silent or exempt it from normal keying gates. |
| Level | Generated audio level, −96 to 0 dB. This is separate from RF drive. |
| Drive Power Source | Drive Slider uses RF Power; Tune Slider uses the transmit band's tune value; Fixed uses Drive Power (Fixed mode). This choice is separate from the TUNE source above. |
| Drive Power (Fixed mode) | Fixed two-tone drive percentage, 0 to 100, used only with Fixed selected. |
| Pulsed two-tone | Chooses the pulsed test instead of continuous generation. It is still a keyed RF test. |
| Invert for LS Modes | Negates both tone frequencies for lower-sideband modes, reversing their signed audio-frequency direction. |
| Freq #2 delay | Delay before the second tone is enabled, 0 to 1000 ms. |
In the desktop TX applet, choose SPEAKERS or PHONES, set Mon Vol: to a comfortable level, then enable MON for a controlled transmit check. This selector and volume route the monitor to this computer's output; they do not change RF drive. MON is off when NereusSDR starts. Check that the radio is actually keyed before judging silence, and check the selected output and its local volume if MON is silent. With PHONES selected, no open headphone device means no audible monitor. Turn MON off after the check to avoid unexpected audio or feedback.
Keep the evidence distinct: Test Mic is local capture before transmit; the TX applet MON is a local listen to audio during transmit; TX mic/ALC meters show only the values that the connected radio/Core supplies; and an independent receiving station is needed to verify the received signal. None of the first three alone establishes over-the-air audio quality.
For a single-tone check, press TUNE instead of MOX. The button changes to TUNING… while the carrier is active; press it again to stop. TUNE is not a voice test and should be used only into an appropriate antenna/load system with station precautions. The TX applet's 2-Tone control is a separate keyed measurement path, configured as described below. PureSignal uses that test path in PureSignal and diversity.
Open File > Settings… > Transmit > Power. Enable Protection SWR > turns on the visual SWR warning threshold; SWR Limit sets that threshold. Ignore when Tune Pwr < and Tune Pwr (W) specify whether SWR protection is ignored below the selected Tune power. That option disables SWR protection during low-power Tune; use it only when that is the intended station policy. Reduce Pwr if protected asks the radio to wind back drive when high-SWR protection engages. These controls apply immediately and affect the Core's protection behavior, including from a remote desktop when the Core offers the setting.
In the same Power page, External TX Inhibit contains Update with TX Inhibit state and Reversed logic. Enable monitoring when the connected radio's external inhibit input is wired and intended to control the TX gate. Reverse logic only when the hardware's asserted/deasserted levels require it. Confirm the resulting inhibit state in the TX readiness indication before keying. Do not mask an inhibit by changing logic as a troubleshooting guess.
Open File > Settings… > General > Options > Time Out Timers to review station key timeouts. MOX sets a maximum duration for MOX and other radio/computer keys. Ping stops MOX if the configured host cannot be pinged for the selected interval; choose a host that this station can reliably reach, since a blocked ICMP path can unkey a healthy RF link. The Def button restores the displayed default ping host. Phone and iPad sets the separate timeout for mobile transmissions. These timeout values are Core/station settings, apply immediately, and are evaluated from key-down. Choose limits that suit the station, then verify the enabled state and seconds readback. A timeout ending TX is a protective unkey; inspect the corresponding timer and network condition before keying again.
The General > Options page also includes Prevent TX'ing on a different band to the RX band. When enabled, it can block a TX slice whose band differs from the receive band; confirm both slice bands before changing that station-wide policy. Receive Only is a broader station mode that disables TX controls. Turning off a safeguard merely to clear a refusal can permit an unintended transmission, so first identify why the current selection violates the policy.
If a TX inhibit, high SWR condition, PA fault, band protection, receive-only setting, or shared transmit lock prevents keying, read the status message beside the blocked control. Check the physical antenna/load and accessory interlock first, correct the identified station condition, and then confirm the blocker clears. A red/disabled button is not a request to bypass a protection. Some protection and radio settings are unavailable while transmitting or while another Core operation is in progress; unkey and wait for the stated operation to finish.
Open File > Settings… > General > Options while the station is receiving. These choices affect the Core/radio, including requests from a remote window.
Extended, on the same Options page, changes the Core's shared extended transmit policy. In this build it bypasses the software frequency/passband restrictions and the affected region-specific mode-policy branch. Supported TX-mode and different-band checks remain in place, along with ownership and station interlocks. It grants no operating permission and changes no displayed band-plan presentation.
Set it only for an intentional station policy while off air. The hosting desktop can hold the edit while another device owns TX; a remote window needs the Core's supported transmit-setting version and transmit permission. A disabled checkbox gives that reason. After an edit, check the Core's returned check state and any refusal; a reverted check means the policy did not change. Restore the previous state when ending the intended extended-policy session. An old saved per-computer Extended value is not the active Core policy.
After any request, use the accepted check/selection and readiness state as the result. A reverted value or displayed refusal means the requested policy has not become operative. Reconnect and recheck before trying to key after a link-loss event.
Figure 4. The TX applet while receiving: RF Power (1), Tune Pwr (2), TUNE (3), MOX (4), monitor output and volume (5), processing (6), profile selector (7), and TX BW (8). Neither MOX nor TUNE is keyed in this capture. The displayed values are not recommended starting levels.