Editing SimTX API v24/Packets/TransmitterSessionRequest (section)

== Fields ==
Numeric payloads are a single big-endian <code>f32</code> or <code>i32</code> with <code>length = 4</code>. String payloads (callsign, modulation, source type) are standard UTF-8 without any further length prefix. GeoPoint and AntennaConfig payloads use their usual encoding, with <code>length</code> giving their total size.

The ''Live'' column marks fields that can later be changed with [[SimTX API v24/Packets/TxUpdate|TxUpdate]].

{| class="wikitable sortable"
! ID !! Field !! Payload !! Required !! Valid range !! Default !! Live
|-
| 1 || <code>callsign</code> || UTF-8 || Yes || 1–64 printable characters, ≤ 64 bytes || — ||
|-
| 2 || <code>location</code> || [[SimTX API v24/Data types#GeoPoint|GeoPoint]] (24 bytes) || Yes || Valid coordinates || — ||
|-
| 3 || <code>antenna</code> || [[SimTX API v24/Data types#AntennaConfig|AntennaConfig]] || Yes || See Data types || — ||
|-
| 4 || <code>modulation</code> || UTF-8 || Yes || A [[SimTX API v24/Data types#Modulation|Modulation]] name, ≤ 64 bytes || — ||
|-
| 5 || <code>frequencyHz</code> || f32 || Yes || > 0; values above 3 GHz are reduced to 3 GHz || — || Yes
|-
| 6 || <code>powerWatts</code> || f32 || Yes || ≥ 0; reduced to at most 1,000,000 and then to the account's <code>tx.pa_limit</code> || — || Yes
|-
| 7 || <code>sourceType</code> || UTF-8 || Yes || A [[SimTX API v24/Data types#TransmissionSourceType|TransmissionSourceType]] name || — ||
|-
| 8 || <code>sampleRate</code> || i32 || Yes || > 0 || — ||
|-
| 9 || <code>audioGain</code> || f32 || Yes || ≥ 0; values above 100 are reduced to 100 || — ||
|-
| 10 || <code>txBandwidthHz</code> || f32 || Yes || > 0; values above 10 MHz are reduced to 10 MHz || — || Yes
|-
| 11 || <code>audioLowCutHz</code> || f32 || Yes || ≥ 0 || — || Yes
|-
| 12 || <code>toneHz</code> || f32 || Yes || ≥ 0 || — ||
|-
| 13 || <code>dutyCycle</code> || f32 || Yes || 0–1 || — ||
|-
| 14 || <code>finalDriveDb</code> || f32 || No || −40 to 40 || 0 || Yes
|-
| 15 || <code>paHeadroomDb</code> || f32 || No || 0.1 to 40 || 12 || Yes
|-
| 16 || <code>audioCompressionDb</code> || f32 || No || 0 to 30 || 1.5 || Yes
|-
| 17 || <code>paSoftness</code> || f32 || No || 0.5 to 10 || 2.8 ||
|-
| 18 || <code>paAmPmDeg</code> || f32 || No || 0 to 45 || 6 ||
|-
| 19 || <code>carrierLeakDb</code> || f32 || No || 0 to 120 (dB below carrier) || 60 ||
|-
| 20 || <code>oppositeSidebandSuppressionDb</code> || f32 || No || 0 to 120 || 60 ||
|-
| 21 || <code>frequencyOffsetHz</code> || f32 || No || −10,000 to 10,000 || 0 ||
|-
| 22 || <code>mainsHumDb</code> || f32 || No || 0 to 120 (dB down) || 120 ||
|-
| 23 || <code>mainsHumHz</code> || f32 || No || 0 to 400 || 0 ||
|-
| 24 || <code>amModulationIndex</code> || f32 || No || 0 to 1.2 || 0.85 ||
|-
| 25 || <code>paSupplySagDb</code> || f32 || No || 0 to 30 || 0 ||
|-
| 26 || <code>txNoiseFloorDb</code> || f32 || No || 0 to 160 || 120 ||
|-
| 27 || <code>oscillatorPhaseNoiseDb</code> || f32 || No || 0 to 160 || 120 ||
|-
| 28 || <code>cwKeyRiseMs</code> || f32 || No || 0 to 50 || 5 ||
|}

Fields 14 to 28 model the transmitter's own imperfections: amplifier compression and AM-to-PM conversion, carrier leakage, unwanted sideband, frequency error, mains hum, supply sag, broadband noise and phase noise. They are rendered '''in-band''', around the carrier; harmonics and far-out spurious emissions are not simulated. [[Advanced Transmitter Settings]] explains what each one sounds like. A client that does not care may omit them all.

<code>toneHz</code> and <code>dutyCycle</code> are required for historical reasons. Clients that do not use them send <code>0</code> and <code>1</code>.