diff --git a/.skills/compose-ui/strings-index.txt b/.skills/compose-ui/strings-index.txt
index ecab43248d..781c26a819 100644
--- a/.skills/compose-ui/strings-index.txt
+++ b/.skills/compose-ui/strings-index.txt
@@ -832,6 +832,7 @@ gps_receive_gpio
 gps_transmit_gpio
 grant_permission
 green
+ham_long_name_summary
 hardware
 hardware_model
 heading
diff --git a/core/domain/src/commonMain/kotlin/org/meshtastic/core/domain/usecase/settings/RadioConfigUseCase.kt b/core/domain/src/commonMain/kotlin/org/meshtastic/core/domain/usecase/settings/RadioConfigUseCase.kt
index 1e46dbb830..ba2cdb9306 100644
--- a/core/domain/src/commonMain/kotlin/org/meshtastic/core/domain/usecase/settings/RadioConfigUseCase.kt
+++ b/core/domain/src/commonMain/kotlin/org/meshtastic/core/domain/usecase/settings/RadioConfigUseCase.kt
@@ -52,8 +52,8 @@ open class RadioConfigUseCase constructor(private val radioController: RadioCont
     }
 
     /**
-     * Enables amateur-radio (ham) mode on the locally connected node via `set_ham_mode`. At protobufs 2.7.25 only
-     * `call_sign` and `short_name` are user-supplied; `long_name` becomes settable when meshtastic/protobufs#941 ships.
+     * Enables amateur-radio (ham) mode on the locally connected node via `set_ham_mode`. `call_sign`, `short_name` and
+     * the optional `long_name` are user-supplied; `tx_power`/`frequency` are filled in by the controller.
      *
      * @param destNum The node number to update (must be the local node).
      * @param hamParameters The ham onboarding parameters.
diff --git a/core/model/src/commonMain/kotlin/org/meshtastic/core/model/HamName.kt b/core/model/src/commonMain/kotlin/org/meshtastic/core/model/HamName.kt
new file mode 100644
index 0000000000..cc0b7d34f0
--- /dev/null
+++ b/core/model/src/commonMain/kotlin/org/meshtastic/core/model/HamName.kt
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2026 Meshtastic LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.meshtastic.core.model
+
+/**
+ * The owner name of a licensed (ham) node, which firmware builds from two `HamParameters` fields.
+ *
+ * `AdminModule::handleSetHamMode()` joins the call sign and the optional `long_name` with [SEPARATOR] — the form hams
+ * already use on the air — so `KD2ABC` plus `Attic Heltec` becomes `KD2ABC//Attic Heltec`, and a ham who supplied no
+ * long name is named after the bare call sign. The device only ever reports that composed name back as
+ * `User.long_name`, so editing either half means splitting it again: [split] and [compose] are inverses over every name
+ * firmware can produce.
+ */
+object HamName {
+
+    /** What firmware puts between the call sign and the long name. */
+    const val SEPARATOR = "//"
+
+    /** Usable bytes in `HamParameters.call_sign` (`max_size:8`, one byte of which is the NUL terminator). */
+    const val MAX_CALL_SIGN_BYTES = 7
+
+    /** Usable bytes in `HamParameters.long_name` (`max_size:15`, one byte of which is the NUL terminator). */
+    const val MAX_LONG_NAME_BYTES = 14
+
+    /**
+     * Joins the two halves the way firmware does. A blank [longName] yields the bare [callSign] — firmware treats unset
+     * and whitespace-only alike, so composing a separator for either would not match what the node stores.
+     */
+    fun compose(callSign: String, longName: String): String =
+        if (longName.isBlank()) callSign else callSign + SEPARATOR + longName
+
+    /**
+     * Splits an owner long name into its call sign and long name at the first [SEPARATOR].
+     *
+     * A name with no separator is all call sign, which is what firmware writes for a ham who supplied no long name.
+     */
+    fun split(ownerLongName: String): Pair<String, String> {
+        val at = ownerLongName.indexOf(SEPARATOR)
+        return if (at < 0) {
+            ownerLongName to ""
+        } else {
+            ownerLongName.substring(0, at) to ownerLongName.substring(at + SEPARATOR.length)
+        }
+    }
+
+    /**
+     * Reshapes an existing owner long name for ham onboarding, so enabling licensed mode does not discard a name the
+     * operator already chose.
+     *
+     * A name that can still serve as a call sign is returned untouched — including one this app composed during an
+     * earlier licensing, whose halves survive as they are. Anything wider is demoted to the descriptive half, clipped
+     * to [MAX_LONG_NAME_BYTES], leaving the call sign empty for the operator to fill in.
+     */
+    fun forOnboarding(ownerLongName: String): String {
+        val (callSign, longName) = split(ownerLongName)
+        if (callSign.utf8Size() <= MAX_CALL_SIGN_BYTES) return ownerLongName
+        return compose("", longName.ifBlank { callSign }.limitToBytes(MAX_LONG_NAME_BYTES))
+    }
+
+    /**
+     * Reshapes an owner long name on the way back out of licensed mode.
+     *
+     * A fully composed name survives untouched — `KD2ABC//Attic Heltec` is exactly what the node is called, and an
+     * operator clearing the toggle has no reason to lose it. Only the half-filled name left by an abandoned onboarding,
+     * where no call sign was ever entered, is flattened, so a stray separator cannot become the node's name.
+     */
+    fun forUnlicensing(ownerLongName: String): String {
+        val (callSign, longName) = split(ownerLongName)
+        return if (callSign.isBlank()) longName else ownerLongName
+    }
+}
+
+/** UTF-8 length in bytes, the unit every `max_size` in the protobuf options is counted in. */
+fun String.utf8Size(): Int = encodeToByteArray().size
+
+/** Clips to at most [maxBytes] of UTF-8, stepping whole code points so a surrogate pair is never cut in half. */
+private fun String.limitToBytes(maxBytes: Int): String {
+    if (utf8Size() <= maxBytes) return this
+    var end = 0
+    var used = 0
+    while (end < length) {
+        val step = if (this[end].isHighSurrogate() && end + 1 < length && this[end + 1].isLowSurrogate()) 2 else 1
+        val bytes = substring(end, end + step).utf8Size()
+        if (used + bytes > maxBytes) break
+        used += bytes
+        end += step
+    }
+    return substring(0, end)
+}
diff --git a/core/model/src/commonTest/kotlin/org/meshtastic/core/model/HamNameTest.kt b/core/model/src/commonTest/kotlin/org/meshtastic/core/model/HamNameTest.kt
new file mode 100644
index 0000000000..e54ed96224
--- /dev/null
+++ b/core/model/src/commonTest/kotlin/org/meshtastic/core/model/HamNameTest.kt
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2026 Meshtastic LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.meshtastic.core.model
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+/**
+ * Locks down the `CALLSIGN//Long name` composition the app has to agree with firmware's `handleSetHamMode()` on: the
+ * app builds it optimistically and re-splits whatever the device reports back, so a disagreement would show the
+ * operator a name their node does not have.
+ */
+class HamNameTest {
+
+    @Test
+    fun compose_joins_the_two_halves_with_the_separator() {
+        assertEquals("KD2ABC//Attic Heltec", HamName.compose("KD2ABC", "Attic Heltec"))
+    }
+
+    @Test
+    fun compose_omits_the_separator_when_the_long_name_is_unset() {
+        // Firmware reads unset and whitespace-only alike, so neither may leave a dangling separator behind.
+        assertEquals("KD2ABC", HamName.compose("KD2ABC", ""))
+        assertEquals("KD2ABC", HamName.compose("KD2ABC", "   "))
+    }
+
+    @Test
+    fun split_separates_a_composed_name() {
+        assertEquals("KD2ABC" to "Attic Heltec", HamName.split("KD2ABC//Attic Heltec"))
+    }
+
+    @Test
+    fun split_reads_a_name_without_a_separator_as_all_call_sign() {
+        assertEquals("KD2ABC" to "", HamName.split("KD2ABC"))
+        assertEquals("" to "", HamName.split(""))
+    }
+
+    @Test
+    fun split_keeps_a_later_separator_inside_the_long_name() {
+        // Only the first separator divides the halves; firmware composes on the first one too.
+        assertEquals("KD2ABC" to "a//b", HamName.split("KD2ABC//a//b"))
+    }
+
+    @Test
+    fun split_round_trips_every_name_compose_can_build() {
+        listOf(
+            "KD2ABC" to "Attic Heltec",
+            "KD2ABC" to "",
+            "" to "Attic Heltec",
+            "KD2ABC" to "a//b",
+        ).forEach { (callSign, longName) ->
+            assertEquals(callSign to longName, HamName.split(HamName.compose(callSign, longName)))
+        }
+    }
+
+    @Test
+    fun the_widest_pair_the_proto_can_carry_fits_the_firmware_owner_name() {
+        val widest = HamName.compose("KD2ABCD", "Attic Heltec 3")
+        assertEquals(HamName.MAX_CALL_SIGN_BYTES, "KD2ABCD".utf8Size())
+        assertEquals(HamName.MAX_LONG_NAME_BYTES, "Attic Heltec 3".utf8Size())
+        // MAX_LONG_NAME_BYTES in firmware's NodeDB is 24; the composed pair has to arrive whole.
+        assertTrue(widest.utf8Size() <= 24, "composed name is ${widest.utf8Size()} bytes")
+    }
+
+    @Test
+    fun forOnboarding_leaves_a_name_that_can_be_a_call_sign_alone() {
+        assertEquals("KD2ABC", HamName.forOnboarding("KD2ABC"))
+        assertEquals("KD2ABCD", HamName.forOnboarding("KD2ABCD"))
+        assertEquals("", HamName.forOnboarding(""))
+    }
+
+    @Test
+    fun forOnboarding_leaves_an_already_composed_name_alone() {
+        assertEquals("KD2ABC//Attic Heltec", HamName.forOnboarding("KD2ABC//Attic Heltec"))
+    }
+
+    @Test
+    fun forOnboarding_demotes_an_over_long_name_to_the_long_name_half() {
+        // "Attic Heltec" cannot be a call sign, but it is a perfectly good descriptive name — keep it rather than
+        // making the operator retype it.
+        assertEquals("" to "Attic Heltec", HamName.split(HamName.forOnboarding("Attic Heltec")))
+    }
+
+    @Test
+    fun forOnboarding_clips_a_demoted_name_to_the_proto_cap() {
+        val (callSign, longName) = HamName.split(HamName.forOnboarding("Attic Heltec Node Number Three"))
+
+        assertEquals("", callSign)
+        assertEquals("Attic Heltec N", longName)
+        assertEquals(HamName.MAX_LONG_NAME_BYTES, longName.utf8Size())
+    }
+
+    @Test
+    fun forOnboarding_clips_on_a_code_point_boundary() {
+        // Each emoji is a 4-byte, two-UTF-16-char code point, so 14 bytes of budget holds three. The fourth must be
+        // dropped whole rather than cut into an unpaired surrogate.
+        val grinning = "\uD83D\uDE00"
+        val (_, longName) = HamName.split(HamName.forOnboarding(grinning.repeat(5)))
+
+        assertEquals(12, longName.utf8Size())
+        assertEquals(longName, longName.encodeToByteArray().decodeToString(), "clipping split a code point")
+    }
+
+    @Test
+    fun forOnboarding_keeps_the_long_name_when_only_the_call_sign_is_over_long() {
+        assertEquals("" to "Attic Heltec", HamName.split(HamName.forOnboarding("Old Node Name//Attic Heltec")))
+    }
+
+    @Test
+    fun forUnlicensing_keeps_a_composed_name_the_node_actually_has() {
+        assertEquals("KD2ABC//Attic Heltec", HamName.forUnlicensing("KD2ABC//Attic Heltec"))
+        assertEquals("Attic Heltec", HamName.forUnlicensing("Attic Heltec"))
+    }
+
+    @Test
+    fun forUnlicensing_drops_the_separator_left_by_an_abandoned_onboarding() {
+        // Toggling licensed on and back off without entering a callsign must not name the node "//Attic Heltec".
+        assertEquals("Attic Heltec", HamName.forUnlicensing(HamName.forOnboarding("Attic Heltec")))
+        assertEquals("", HamName.forUnlicensing(""))
+    }
+}
diff --git a/core/repository/src/commonMain/kotlin/org/meshtastic/core/repository/AdminController.kt b/core/repository/src/commonMain/kotlin/org/meshtastic/core/repository/AdminController.kt
index 9bfab0acf4..552a56ffcd 100644
--- a/core/repository/src/commonMain/kotlin/org/meshtastic/core/repository/AdminController.kt
+++ b/core/repository/src/commonMain/kotlin/org/meshtastic/core/repository/AdminController.kt
@@ -60,11 +60,12 @@ interface AdminController {
      * Enables amateur-radio (ham) mode on a node via `AdminMessage.set_ham_mode`.
      *
      * Must target only the locally connected node — firmware ham onboarding is a local operation; the implementation
-     * ignores requests for any other node. The firmware handler rewrites the owner (long_name = call_sign), flips
-     * `is_licensed`, disables encryption, applies [HamParameters.tx_power]/[HamParameters.frequency] to the LoRa config
-     * verbatim, and reboots. The implementation echoes the local node's current LoRa values into those two fields so a
-     * re-send never wipes the node's overrides; caller-supplied [HamParameters.tx_power]/[HamParameters.frequency] are
-     * ignored. Intentionally absent from [AdminEditScope]: ham enablement is not a batch-edit operation.
+     * ignores requests for any other node. The firmware handler rewrites the owner (long_name = call_sign, with an
+     * optional [HamParameters.long_name] appended after `//`), flips `is_licensed`, disables encryption, applies
+     * [HamParameters.tx_power]/[HamParameters.frequency] to the LoRa config verbatim, and reboots. The implementation
+     * echoes the local node's current LoRa values into those two fields so a re-send never wipes the node's overrides;
+     * caller-supplied [HamParameters.tx_power]/[HamParameters.frequency] are ignored. Intentionally absent from
+     * [AdminEditScope]: ham enablement is not a batch-edit operation.
      */
     suspend fun setHamMode(destNum: Int, hamParameters: HamParameters, packetId: Int)
 
diff --git a/core/resources/src/commonMain/composeResources/values/strings.xml b/core/resources/src/commonMain/composeResources/values/strings.xml
index beaeceecca..e4f2302607 100644
--- a/core/resources/src/commonMain/composeResources/values/strings.xml
+++ b/core/resources/src/commonMain/composeResources/values/strings.xml
@@ -190,7 +190,7 @@
     </plurals>
     <string name="calculating">Calculating…</string>
     <string name="call_sign">Call sign</string>
-    <string name="call_sign_summary">Your amateur radio call sign, up to 8 characters</string>
+    <string name="call_sign_summary">Your amateur radio call sign, up to 7 characters</string>
     <string name="camera_permission">Camera permission</string>
     <string name="camera_permission_rationale">Allow camera access to scan QR codes.</string>
     <string name="camera_unavailable">Camera could not start. Try again, or close the scanner and reopen it.</string>
@@ -862,6 +862,7 @@
     <string name="gps_transmit_gpio">GPS Transmit GPIO</string>
     <string name="grant_permission">Grant permission</string>
     <string name="green">Green</string>
+    <string name="ham_long_name_summary">Optional. Appended to your call sign, e.g. KD2ABC//Attic Heltec</string>
     <string name="hardware">Hardware</string>
     <string name="hardware_model">Hardware model</string>
     <string name="heading">Heading</string>
diff --git a/core/service/src/commonMain/kotlin/org/meshtastic/core/service/AdminControllerImpl.kt b/core/service/src/commonMain/kotlin/org/meshtastic/core/service/AdminControllerImpl.kt
index 68345c86c4..ec4596d4af 100644
--- a/core/service/src/commonMain/kotlin/org/meshtastic/core/service/AdminControllerImpl.kt
+++ b/core/service/src/commonMain/kotlin/org/meshtastic/core/service/AdminControllerImpl.kt
@@ -30,6 +30,7 @@ import okio.ByteString.Companion.toByteString
 import org.meshtastic.core.common.util.handledLaunch
 import org.meshtastic.core.common.util.nowMillis
 import org.meshtastic.core.common.util.nowSeconds
+import org.meshtastic.core.model.HamName
 import org.meshtastic.core.model.Position
 import org.meshtastic.core.repository.AdminController
 import org.meshtastic.core.repository.AdminEditScope
@@ -110,7 +111,7 @@ internal class AdminControllerImpl(
         nodeManager.handleReceivedUser(
             destNum,
             currentUser.copy(
-                long_name = hamParameters.call_sign,
+                long_name = HamName.compose(hamParameters.call_sign, hamParameters.long_name),
                 short_name = hamParameters.short_name,
                 is_licensed = true,
             ),
diff --git a/core/service/src/commonTest/kotlin/org/meshtastic/core/service/RadioControllerImplTest.kt b/core/service/src/commonTest/kotlin/org/meshtastic/core/service/RadioControllerImplTest.kt
index 685695eb28..0b812c5730 100644
--- a/core/service/src/commonTest/kotlin/org/meshtastic/core/service/RadioControllerImplTest.kt
+++ b/core/service/src/commonTest/kotlin/org/meshtastic/core/service/RadioControllerImplTest.kt
@@ -1558,14 +1558,42 @@ class RadioControllerImplTest {
                 sentMessage = (it.args[3] as () -> AdminMessage)()
             }
 
-        controller.setHamMode(123, HamParameters(call_sign = "KK7ABC", short_name = "KK7A"), 42)
+        controller.setHamMode(
+            123,
+            HamParameters(call_sign = "KK7ABC", short_name = "KK7A", long_name = "Attic Heltec"),
+            42,
+        )
 
         val ham = sentMessage?.set_ham_mode
         assertEquals("KK7ABC", ham?.call_sign)
         assertEquals("KK7A", ham?.short_name)
+        assertEquals("Attic Heltec", ham?.long_name)
         // Current LoRa values are echoed so a re-send never wipes the node's overrides.
         assertEquals(20, ham?.tx_power)
         assertEquals(915.5f, ham?.frequency)
+        // The optimistic name has to match what firmware composes, or the node reads as renamed until its NodeInfo
+        // lands and silently corrects it.
+        verify {
+            nodeManager.handleReceivedUser(
+                123,
+                existingUser.copy(long_name = "KK7ABC//Attic Heltec", short_name = "KK7A", is_licensed = true),
+                0,
+                false,
+            )
+        }
+    }
+
+    @Test
+    fun setHamModeWithoutALongNameNamesTheNodeAfterTheCallSignAlone() = runTest {
+        val controller = createController(scope = backgroundScope, myNodeNum = 123)
+        val existingUser = User(id = "!0000007b", long_name = "Old Name", short_name = "OLD")
+        every { nodeManager.nodeDBbyNodeNum } returns mapOf(123 to Node(num = 123, user = existingUser))
+        every { radioConfigRepository.localConfigFlow } returns MutableStateFlow(LocalConfig())
+        everySuspend { commandSender.sendAdmin(any(), any(), any(), any()) } returns Unit
+
+        controller.setHamMode(123, HamParameters(call_sign = "KK7ABC", short_name = "KK7A"), 42)
+
+        // long_name is optional: firmware leaves the bare call sign rather than a dangling "//".
         verify {
             nodeManager.handleReceivedUser(
                 123,
diff --git a/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModel.kt b/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModel.kt
index 053f371b35..53229fb43a 100644
--- a/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModel.kt
+++ b/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModel.kt
@@ -57,6 +57,7 @@ import org.meshtastic.core.domain.usecase.settings.ProcessRadioResponseUseCase
 import org.meshtastic.core.domain.usecase.settings.RadioConfigUseCase
 import org.meshtastic.core.domain.usecase.settings.RadioResponseResult
 import org.meshtastic.core.model.ConnectionState
+import org.meshtastic.core.model.HamName
 import org.meshtastic.core.model.MqttConnectionState
 import org.meshtastic.core.model.MqttProbeStatus
 import org.meshtastic.core.model.MyNodeInfo
@@ -446,12 +447,13 @@ open class RadioConfigViewModel(
     private fun setHamMode(destNum: Int, user: User) {
         safeLaunch(tag = "setHamMode") {
             _radioConfigState.update { it.copy(userConfig = user) }
-            // The form's long-name field carries the callsign while licensed (iOS parity).
-            // When meshtastic/protobufs#941 ships, add long_name here.
+            // While licensed the form's long name is the composed `CALLSIGN//Long name`; firmware rebuilds that same
+            // composition from the two HamParameters fields, so send the halves rather than the whole.
+            val (callSign, longName) = HamName.split(user.long_name)
             expectRestartIfLocal(RebootBehavior.ALWAYS)
             radioConfigUseCase.setHamMode(
                 destNum,
-                HamParameters(call_sign = user.long_name, short_name = user.short_name),
+                HamParameters(call_sign = callSign, short_name = user.short_name, long_name = longName),
                 onRequestId = ::registerWriteRequestId,
             )
         }
diff --git a/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/component/UserConfigItemList.kt b/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/component/UserConfigItemList.kt
index 26553ef905..db541d3d82 100644
--- a/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/component/UserConfigItemList.kt
+++ b/feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/radio/component/UserConfigItemList.kt
@@ -16,6 +16,8 @@
  */
 package org.meshtastic.feature.settings.radio.component
 
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.text.KeyboardActions
 import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.material3.CardDefaults
@@ -23,16 +25,21 @@ import androidx.compose.material3.HorizontalDivider
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalFocusManager
+import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.text.input.ImeAction
 import androidx.compose.ui.text.input.KeyboardType
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import org.jetbrains.compose.resources.stringResource
 import org.meshtastic.core.model.Capabilities
+import org.meshtastic.core.model.HamName
 import org.meshtastic.core.model.isUnmessageableRole
+import org.meshtastic.core.model.utf8Size
 import org.meshtastic.core.resources.Res
 import org.meshtastic.core.resources.call_sign
 import org.meshtastic.core.resources.call_sign_summary
+import org.meshtastic.core.resources.ham_long_name_summary
 import org.meshtastic.core.resources.hardware_model
 import org.meshtastic.core.resources.long_name
 import org.meshtastic.core.resources.node_id
@@ -46,9 +53,14 @@ import org.meshtastic.core.ui.component.RegularPreference
 import org.meshtastic.core.ui.component.SwitchPreference
 import org.meshtastic.core.ui.component.TitledCard
 import org.meshtastic.feature.settings.radio.RadioConfigViewModel
+import org.meshtastic.proto.User
 
 private const val LONG_NAME_MAX_LENGTH = 39 // long_name max_size:40
-private const val CALL_SIGN_MAX_LENGTH = 8 // iOS parity; firmware sets long_name from the callsign
+private const val SHORT_NAME_MAX_LENGTH = 4 // short_name max_size:5
+
+internal const val USER_LONG_NAME_TEST_TAG = "user_long_name"
+internal const val HAM_LONG_NAME_TEST_TAG = "ham_long_name"
+internal const val USER_SHORT_NAME_TEST_TAG = "user_short_name"
 
 @Composable
 fun UserConfigScreen(viewModel: RadioConfigViewModel, onBack: () -> Unit) {
@@ -60,11 +72,11 @@ fun UserConfigScreen(viewModel: RadioConfigViewModel, onBack: () -> Unit) {
 
     // Ham onboarding repurposes the long-name field as the callsign, for the local node only (iOS parity).
     val hamMode = formState.value.is_licensed && state.isLocal
-    val longNameMax = if (hamMode) CALL_SIGN_MAX_LENGTH else LONG_NAME_MAX_LENGTH
-    val validLongName = formState.value.long_name.isNotBlank() && formState.value.long_name.length <= longNameMax
+    val longNameValue = if (hamMode) HamName.split(formState.value.long_name).first else formState.value.long_name
+    val longNameMax = if (hamMode) HamName.MAX_CALL_SIGN_BYTES else LONG_NAME_MAX_LENGTH
+    val validLongName = longNameValue.isNotBlank() && longNameValue.utf8Size() <= longNameMax
     val validShortName = formState.value.short_name.isNotBlank()
     val validNames = validLongName && validShortName
-    val focusManager = LocalFocusManager.current
 
     RadioConfigScreenList(
         title = stringResource(Res.string.user),
@@ -83,29 +95,12 @@ fun UserConfigScreen(viewModel: RadioConfigViewModel, onBack: () -> Unit) {
                     onClick = {},
                 )
                 HorizontalDivider()
-                EditTextPreference(
-                    title = stringResource(if (hamMode) Res.string.call_sign else Res.string.long_name),
-                    value = formState.value.long_name,
-                    summary = if (hamMode) stringResource(Res.string.call_sign_summary) else null,
-                    maxSize = longNameMax,
+                UserNameFields(
+                    formState = formState,
+                    hamMode = hamMode,
                     enabled = state.connected,
-                    isError = !validLongName,
-                    keyboardOptions =
-                    KeyboardOptions.Default.copy(keyboardType = KeyboardType.Text, imeAction = ImeAction.Done),
-                    keyboardActions = KeyboardActions(onDone = { focusManager.clearFocus() }),
-                    onValueChanged = { formState.value = formState.value.copy(long_name = it) },
-                )
-                HorizontalDivider()
-                EditTextPreference(
-                    title = stringResource(Res.string.short_name),
-                    value = formState.value.short_name,
-                    maxSize = 4, // short_name max_size:5
-                    enabled = state.connected,
-                    isError = !validShortName,
-                    keyboardOptions =
-                    KeyboardOptions.Default.copy(keyboardType = KeyboardType.Text, imeAction = ImeAction.Done),
-                    keyboardActions = KeyboardActions(onDone = { focusManager.clearFocus() }),
-                    onValueChanged = { formState.value = formState.value.copy(short_name = it) },
+                    isLongNameError = !validLongName,
+                    isShortNameError = !validShortName,
                 )
                 HorizontalDivider()
                 RegularPreference(
@@ -131,12 +126,18 @@ fun UserConfigScreen(viewModel: RadioConfigViewModel, onBack: () -> Unit) {
                     signingSupported = state.metadata?.has_xeddsa,
                     onCheckedChange = { licensed ->
                         val longName = formState.value.long_name
-                        // The field becomes the callsign: clear an over-long name so the user enters one.
-                        val clearForCallsign = licensed && state.isLocal && longName.length > CALL_SIGN_MAX_LENGTH
+                        // The long-name field becomes the callsign while licensed, so reshape the name for the mode
+                        // being entered: one too wide to be a callsign is demoted to the ham long name rather than
+                        // discarded, and abandoning onboarding does not leave a stray separator behind.
                         formState.value =
                             formState.value.copy(
                                 is_licensed = licensed,
-                                long_name = if (clearForCallsign) "" else longName,
+                                long_name =
+                                when {
+                                    !state.isLocal -> longName
+                                    licensed -> HamName.forOnboarding(longName)
+                                    else -> HamName.forUnlicensing(longName)
+                                },
                             )
                     },
                 )
@@ -144,3 +145,72 @@ fun UserConfigScreen(viewModel: RadioConfigViewModel, onBack: () -> Unit) {
         }
     }
 }
+
+/**
+ * The owner name fields: long name (relabelled "Call sign" during ham onboarding), the ham-only long name, and the
+ * short name.
+ *
+ * While licensed, a node's owner long name is the `CALLSIGN//Long name` firmware composes from the two
+ * [org.meshtastic.proto.HamParameters] name fields. The device only ever reports that composed name back, so the two
+ * halves are split apart for editing and rejoined on every keystroke — [formState] stays the single source of truth,
+ * which is what keeps Discard, the dirty check and process-death restore working unchanged.
+ */
+@Composable
+internal fun UserNameFields(
+    formState: ConfigState<User>,
+    hamMode: Boolean,
+    enabled: Boolean,
+    isLongNameError: Boolean,
+    isShortNameError: Boolean,
+) {
+    val focusManager = LocalFocusManager.current
+    val (callSign, hamLongName) = remember(formState.value.long_name) { HamName.split(formState.value.long_name) }
+    val keyboardOptions = KeyboardOptions.Default.copy(keyboardType = KeyboardType.Text, imeAction = ImeAction.Done)
+    val keyboardActions = KeyboardActions(onDone = { focusManager.clearFocus() })
+
+    Column(modifier = Modifier.fillMaxWidth()) {
+        EditTextPreference(
+            title = stringResource(if (hamMode) Res.string.call_sign else Res.string.long_name),
+            value = if (hamMode) callSign else formState.value.long_name,
+            summary = if (hamMode) stringResource(Res.string.call_sign_summary) else null,
+            maxSize = if (hamMode) HamName.MAX_CALL_SIGN_BYTES else LONG_NAME_MAX_LENGTH,
+            enabled = enabled,
+            isError = isLongNameError,
+            keyboardOptions = keyboardOptions,
+            keyboardActions = keyboardActions,
+            modifier = Modifier.testTag(USER_LONG_NAME_TEST_TAG),
+            onValueChanged = {
+                val longName = if (hamMode) HamName.compose(it, hamLongName) else it
+                formState.value = formState.value.copy(long_name = longName)
+            },
+        )
+        if (hamMode) {
+            HorizontalDivider()
+            // Optional: firmware appends it to the callsign, so an empty field names the node after the callsign.
+            EditTextPreference(
+                title = stringResource(Res.string.long_name),
+                value = hamLongName,
+                summary = stringResource(Res.string.ham_long_name_summary),
+                maxSize = HamName.MAX_LONG_NAME_BYTES,
+                enabled = enabled,
+                isError = false,
+                keyboardOptions = keyboardOptions,
+                keyboardActions = keyboardActions,
+                modifier = Modifier.testTag(HAM_LONG_NAME_TEST_TAG),
+                onValueChanged = { formState.value = formState.value.copy(long_name = HamName.compose(callSign, it)) },
+            )
+        }
+        HorizontalDivider()
+        EditTextPreference(
+            title = stringResource(Res.string.short_name),
+            value = formState.value.short_name,
+            maxSize = SHORT_NAME_MAX_LENGTH,
+            enabled = enabled,
+            isError = isShortNameError,
+            keyboardOptions = keyboardOptions,
+            keyboardActions = keyboardActions,
+            modifier = Modifier.testTag(USER_SHORT_NAME_TEST_TAG),
+            onValueChanged = { formState.value = formState.value.copy(short_name = it) },
+        )
+    }
+}
diff --git a/feature/settings/src/commonTest/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModelTest.kt b/feature/settings/src/commonTest/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModelTest.kt
index 4af73ef6dd..ca85eb8a49 100644
--- a/feature/settings/src/commonTest/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModelTest.kt
+++ b/feature/settings/src/commonTest/kotlin/org/meshtastic/feature/settings/radio/RadioConfigViewModelTest.kt
@@ -958,6 +958,28 @@ class RadioConfigViewModelTest {
         verifySuspend(exactly(0)) { radioConfigUseCase.setOwner(any(), any(), any()) }
     }
 
+    @Test
+    fun `saveUserConfig splits a composed ham name into call sign and long name`() = runTest {
+        val node = Node(num = 123, user = User(id = "!123"))
+        nodeRepository.setNodes(listOf(node))
+        nodeRepository.setMyNodeInfo(myNodeInfo(myNodeNum = 123))
+        viewModel = createViewModel()
+
+        // The User form carries the composed name firmware builds; set_ham_mode wants the halves back.
+        val user = User(long_name = "KK7ABC//Attic Heltec", short_name = "KK7A", is_licensed = true)
+        everySuspend { radioConfigUseCase.setHamMode(any(), any(), any()) } returns 42
+
+        viewModel.saveUserConfig(user)
+
+        verifySuspend {
+            radioConfigUseCase.setHamMode(
+                123,
+                HamParameters(call_sign = "KK7ABC", short_name = "KK7A", long_name = "Attic Heltec"),
+                any(),
+            )
+        }
+    }
+
     @Test
     fun `saveUserConfig sends setOwner for unlicensed user`() = runTest {
         val node = Node(num = 123, user = User(id = "!123"))
diff --git a/feature/settings/src/commonTest/kotlin/org/meshtastic/feature/settings/radio/component/UserNameFieldsTest.kt b/feature/settings/src/commonTest/kotlin/org/meshtastic/feature/settings/radio/component/UserNameFieldsTest.kt
new file mode 100644
index 0000000000..52558d1f02
--- /dev/null
+++ b/feature/settings/src/commonTest/kotlin/org/meshtastic/feature/settings/radio/component/UserNameFieldsTest.kt
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2026 Meshtastic LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.meshtastic.feature.settings.radio.component
+
+import androidx.compose.ui.semantics.SemanticsProperties
+import androidx.compose.ui.semantics.getOrNull
+import androidx.compose.ui.test.ComposeUiTest
+import androidx.compose.ui.test.ExperimentalTestApi
+import androidx.compose.ui.test.SemanticsNodeInteraction
+import androidx.compose.ui.test.hasAnyAncestor
+import androidx.compose.ui.test.hasSetTextAction
+import androidx.compose.ui.test.hasTestTag
+import androidx.compose.ui.test.onNodeWithTag
+import androidx.compose.ui.test.performTextClearance
+import androidx.compose.ui.test.performTextInput
+import androidx.compose.ui.test.v2.runComposeUiTest
+import org.meshtastic.core.ui.theme.AppTheme
+import org.meshtastic.proto.User
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+/**
+ * A licensed node's owner long name is the `CALLSIGN//Long name` firmware composes, edited here as two fields. These
+ * lock down that the split and the rejoin stay inverses through the UI — a regression would silently send the operator
+ * a name they never typed.
+ */
+@OptIn(ExperimentalTestApi::class)
+class UserNameFieldsTest {
+
+    /** Renders [UserNameFields] over [user] and returns an accessor for the edited message. */
+    private fun ComposeUiTest.showNameFields(user: User, hamMode: Boolean): () -> User {
+        lateinit var formState: ConfigState<User>
+        setContent {
+            AppTheme {
+                formState = rememberConfigState(user)
+                UserNameFields(
+                    formState = formState,
+                    hamMode = hamMode,
+                    enabled = true,
+                    isLongNameError = false,
+                    isShortNameError = false,
+                )
+            }
+        }
+        return { formState.value }
+    }
+
+    /** The text field itself: [EditTextPreference] tags its wrapping column, which carries no text actions. */
+    private fun ComposeUiTest.field(tag: String): SemanticsNodeInteraction =
+        onNode(hasSetTextAction() and hasAnyAncestor(hasTestTag(tag)))
+
+    private fun ComposeUiTest.fieldText(tag: String): String =
+        field(tag).fetchSemanticsNode().config.getOrNull(SemanticsProperties.EditableText)?.text.orEmpty()
+
+    @Test
+    fun `the ham long name field only exists while licensed`() = runComposeUiTest {
+        showNameFields(User(long_name = "Attic Heltec", short_name = "ATTC"), hamMode = false)
+
+        onNodeWithTag(HAM_LONG_NAME_TEST_TAG).assertDoesNotExist()
+        assertEquals("Attic Heltec", fieldText(USER_LONG_NAME_TEST_TAG))
+    }
+
+    @Test
+    fun `the call sign field shows only the call sign half of a composed name`() = runComposeUiTest {
+        showNameFields(User(long_name = "KD2ABC//Attic Heltec", short_name = "ABC"), hamMode = true)
+
+        assertEquals("KD2ABC", fieldText(USER_LONG_NAME_TEST_TAG))
+        assertEquals("Attic Heltec", fieldText(HAM_LONG_NAME_TEST_TAG))
+    }
+
+    @Test
+    fun `editing the call sign keeps the long name half`() = runComposeUiTest {
+        val user = showNameFields(User(long_name = "KD2ABC//Attic Heltec", short_name = "ABC"), hamMode = true)
+
+        field(USER_LONG_NAME_TEST_TAG).performTextClearance()
+        field(USER_LONG_NAME_TEST_TAG).performTextInput("N0CALL")
+
+        assertEquals("N0CALL//Attic Heltec", user().long_name)
+    }
+
+    @Test
+    fun `editing the long name keeps the call sign`() = runComposeUiTest {
+        val user = showNameFields(User(long_name = "KD2ABC", short_name = "ABC"), hamMode = true)
+
+        field(HAM_LONG_NAME_TEST_TAG).performTextInput("Garage")
+
+        assertEquals("KD2ABC//Garage", user().long_name)
+    }
+
+    @Test
+    fun `clearing the long name leaves the node named after the call sign alone`() = runComposeUiTest {
+        val user = showNameFields(User(long_name = "KD2ABC//Attic Heltec", short_name = "ABC"), hamMode = true)
+
+        field(HAM_LONG_NAME_TEST_TAG).performTextClearance()
+
+        assertEquals("KD2ABC", user().long_name)
+    }
+
+    @Test
+    fun `the widest pair the proto can carry composes whole`() = runComposeUiTest {
+        val user = showNameFields(User(long_name = "KD2ABCD", short_name = "ABC"), hamMode = true)
+
+        field(HAM_LONG_NAME_TEST_TAG).performTextInput("Attic Heltec 3")
+
+        assertEquals("KD2ABCD//Attic Heltec 3", user().long_name)
+    }
+}