Upsate Fox Hunt / Beacon doc

Fox-Hunt-and-Beacon.md

@@ -3,16 +3,36 @@
 
 # Fox Hunt and Beacon
 
-`FOX HUNT / BEACON` is a programmable shortcut action with two complementary modes:
+`FOX HUNT / BEACON` is a programmable shortcut action with two complementary modes built for **ARDF** (Amateur Radio Direction Finding), the "fox hunting" or radio-orienteering discipline:
 
-* **Fox Hunt** is a receive-only signal-strength aid for radio direction finding.
+* **Fox Hunt** is a receive-only signal-strength aid used to home in on a hidden transmitter.
-* **Beacon** turns the radio into the hidden transmitter and periodically sends an identification message in Morse code.
+* **Beacon** turns the radio *into* the hidden transmitter and repeats a Morse identifier on a timed cycle.
 
 The feature opens in Fox Hunt mode. Press either side button while the feature is open to switch between Fox Hunt and Beacon.
 
 > [!WARNING]
 > Beacon starts transmitting immediately when it is selected. Before entering Beacon mode, verify the active TX frequency, power, antenna, `F Lock`, `TXLock`, identification requirements, and the regulations applicable in your country. Do not leave an unattended beacon transmitting where autonomous or periodic transmissions are prohibited.
 
+## About fox hunting (ARDF)
+
+In ARDF, several low-power transmitters (the "foxes") are hidden in the field and competitors use a directional receiver to find them. In the classic IARU format there are **five foxes sharing one frequency**. Each fox transmits **for 60 seconds in turn**, so the cycle repeats every 5 minutes and each fox is silent for the 4 minutes (240 seconds) while the other four are on.
+
+Every fox sends the same `MO` prefix followed by a rising number of dits, so you can tell which one you are hearing by counting the final dits:
+
+| Fox | Sends | Morse | Final dits |
+| --- | --- | --- | --- |
+| 1 | `MOE` | `-- --- ·` | 1 |
+| 2 | `MOI` | `-- --- ··` | 2 |
+| 3 | `MOS` | `-- --- ···` | 3 |
+| 4 | `MOH` | `-- --- ····` | 4 |
+| 5 | `MO5` | `-- --- ·····` | 5 |
+
+A separate **finish (home) beacon** marks the end of the course. It sends `MO` (`-- ---`) and, unlike the timed foxes, transmits *continuously*. This firmware offers `MO` as an identifier but still runs it on the normal transmit/silence cycle rather than a true continuous carrier (see [TX window and idle interval](#tx-window-and-idle-interval)); a short `IDLE` makes it near-constant.
+
+On the 2 m band the foxes use tone-modulated CW (A2A), which is exactly what this firmware transmits: the FM carrier stays up while the `1000 Hz` tone is keyed on and off for each Morse element (MCW).
+
+This feature lets one radio play either role: **Fox Hunt** to search, or **Beacon** to *be* one of the transmitters. With several radios you can lay out a full course — set each one to a different fox (`MOE`, `MOI`, `MOS`, …), one to the `MO` finish beacon, or use the `CALL` identifier for a properly identified beacon on the amateur bands.
+
 ## Assigning the shortcut
 
 Assign `FOX HUNT / BEACON` to one of the customizable shortcuts:
@@ -27,60 +47,90 @@ Trigger the assigned shortcut to open Fox Hunt on the currently selected VFO. Se
 
 ## Fox Hunt mode
 
-Fox Hunt displays the calibrated received level in `dBm`, an S-meter value, a peak reading, and the recent signal trend. The current RX frequency and battery state remain visible.
+Fox Hunt displays the calibrated received level in `dBm`, an S-meter value, held peak (`PK`) and minimum (`MN`) readings, and the recent signal trend. The current RX frequency and battery state remain visible.
 
 The signal scale runs from `S0` to `S9+40`. The main gauge can be either:
 
 * a 13-level staircase covering `S1` through `S9`, then `+10` through `+40`
 * a smoothed scrolling signal history covering approximately the last `18 seconds`
 
-The trend arrow and signed `dBm` difference compare the current level with the level measured roughly one second earlier. An upward arrow means the signal is increasing; a downward arrow means it is decreasing.
+The trend arrow and signed `dBm` difference compare the current level with the level measured roughly one second earlier. An upward arrow means the signal is increasing (you are getting closer); a downward arrow means it is decreasing.
 
 ### Fox Hunt controls
 
+Every setting has its own key — there are no navigation arrows to remember, and each press cycles to the next value.
+
 | Control | Action |
 | --- | --- |
-| `UP` / `DOWN` | Change the receiver attenuation; direction follows the hidden `SetNav` setting |
+| `1` | Toggle between the S-meter staircase and the signal-history graph |
-| `1` | Cycle audio: silent → Geiger-style beeps → received station audio → silent |
+| `2` | Cycle audio: silent → Geiger-style beeps → received station audio → silent |
-| `2` | Toggle between the S-meter staircase and the signal-history graph |
+| `3` | Cycle the receiver attenuation: `0` → `6` → `15` → `27 dB`, then back to `0` |
-| `M` | Reset the peak reading and trend reference |
+| `M` | Reset the peak (`PK`), minimum (`MN`) and trend references |
 | Either side button | Switch immediately to Beacon mode |
 | `EXIT` | Leave Fox Hunt / Beacon and return to the normal radio screen |
 
-Four attenuation levels are available: `0 dB`, `6 dB`, `15 dB`, and `27 dB`. Increase the attenuation when a nearby transmitter drives the meter close to full scale; this makes close-range comparisons easier.
+### Finding the fox
+
+Direction finding with a handheld relies on watching *how the level changes*, not its absolute value:
+
+* **Attenuation** is the key tool as you close in. When a nearby transmitter drives the meter to full scale you lose the ability to tell "closer" from "farther"; add attenuation (`3`) to bring the reading back into the middle of the scale so small changes stay visible. Four levels are available: `0`, `6`, `15`, and `27 dB`.
+* **Body scan** is how you get a bearing without a directional antenna. Hold the radio against your chest and turn slowly through a full circle: your body shields the antenna when it faces the transmitter, producing a clear **minimum (null)** in one direction. Reset with `M`, sweep once, and read the bearing where the level dips.
+* **Peak (`PK`) and minimum (`MN`) hold** keep the strongest and weakest levels seen since the last reset. They bracket a rotation — the deeper `MN` sits below `PK`, the sharper and more reliable the null. Reset both with `M` before each sweep.
+* **Trend** shows whether the signal is rising or falling over the last second — useful while walking a bearing.
+
+The signal-history graph (`1`) also shows the shape of a rotation directly: the valleys in the scrolling trace are your nulls.
 
 In Geiger audio mode, the beeps become faster and higher-pitched as the received level rises. In station-audio mode, the received audio is routed to the speaker. Both audio modes remain silent below approximately `-120 dBm` to avoid continuous noise-floor output.
 
 ## Beacon mode
 
-Beacon uses the active TX VFO frequency, output power, and transmit configuration. As soon as Beacon mode is entered, the radio sends one identification burst, waits for the configured silent interval, and repeats.
+Beacon uses the active TX VFO frequency, output power, and transmit configuration. As soon as Beacon mode is entered, the radio keys up and **repeats the chosen identifier for the whole TX window**, then goes silent for the idle interval, and starts again.
 
-The transmitted message is:
+### Fox identifier
 
-```text
+The `FOX` setting selects what is transmitted:
-<CALLSIGN> BEACON
-```
 
-`<CALLSIGN>` comes from `Message Line 1`, which can be edited with the dedicated Fusion [CHIRP driver](./Programming-with-CHIRP#beacon-identification). Letters are converted to uppercase; letters, digits, and `/` are supported. Unsupported characters are removed. If the line is empty or contains no supported characters, the message falls back to `FOX BEACON`.
+| `FOX` | Message | Notes |
+| --- | --- | --- |
+| `MOE` … `MO5` | `MOE`, `MOI`, `MOS`, `MOH`, `MO5` | The five standard IARU ARDF foxes |
+| `MO` | `MO` | The ARDF finish/home beacon identifier |
+| `CALL` | `<CALLSIGN> MOE` | Your callsign followed by `MOE` — an identified beacon for the amateur bands |
 
-The Morse identification uses a `1000 Hz` tone at approximately `15 WPM`. The FM carrier remains active for the complete message while the tone modulation is keyed on and off for the Morse elements.
+`<CALLSIGN>` comes from `Message Line 1`, which can be edited with the dedicated Fusion [CHIRP driver](./Programming-with-CHIRP#beacon-identification). Letters are converted to uppercase; letters, digits, and `/` are supported, and unsupported characters are removed. If the line is empty or contains no supported characters, `CALL` falls back to a bare `MOE`.
 
-### Beacon interval and controls
+Use the pure `MOE` … `MO5` and `MO` identifiers for ARDF practice or casual "hide the radio" games (for example on PMR); use `CALL` when you must identify with your callsign on the amateur bands. The default is `CALL`. For a finish-beacon feel, select `MO` and set a short `IDLE` so it repeats almost without a gap — note that this is still a cyclic transmission, not a true continuous carrier.
 
-The setting shown as `IDLE` is the silent time after each identification, not the total period between the start of two transmissions.
+The Morse identification uses a `1000 Hz` tone at approximately `12 WPM` (the slow, beginner-friendly pace typical of ARDF foxes). The FM carrier remains active for the whole window while the tone modulation is keyed on and off for the Morse elements.
 
-* default: `30 seconds`
+### TX window and idle interval
-* minimum: `5 seconds`
+
-* maximum: `60 seconds`
+Two timers shape the cycle:
-* adjustment step: `5 seconds`
+
+* **`TX`** — how long the identifier is repeated each time the beacon keys up.
+  * default `30 s`, range `5 s` to `60 s`, step `5 s`
+* **`IDLE`** — the silent time after the window, before the next transmission.
+  * default `30 s`, range `5 s` to `240 s`, step `5 s`
+
+The full period between two transmissions is `TX` + `IDLE`. To reproduce a **classic ARDF fox**, set `TX = 60 s` and `IDLE = 240 s` (on for one minute, silent for four).
+
+During transmission the top line shows the seconds remaining in the current window, counting down live. During the silent phase the screen shows `IDLE` with the countdown to the next burst.
+
+### Beacon controls
+
+The three settings map to the number keys in the order they appear on screen, and **all three can be changed at any time — during transmission as well as during the silent interval**:
 
 | Control | Action |
 | --- | --- |
-| `UP` / `DOWN` | Change the silent interval; direction follows `SetNav` |
+| `1` | Cycle the `TX` window: `5` → `60 s`, then back to `5` |
-| Either side button | Interrupt the current transmission if necessary and return to Fox Hunt |
+| `2` | Cycle the `IDLE` interval: `5` → `240 s`, then back to `5` |
-| `EXIT` | Interrupt the current transmission if necessary and leave Fox Hunt / Beacon |
+| `3` | Cycle the `FOX` identifier: `MOE` → `MOI` → `MOS` → `MOH` → `MO5` → `MO` → `CALL` → `MOE` |
+| `M` | Stop the current transmission and begin a fresh silent interval; during the silent phase, restart the `IDLE` countdown |
+| Either side button | Return to Fox Hunt (interrupts the current transmission if necessary) |
+| `EXIT` | Leave Fox Hunt / Beacon (interrupts the current transmission if necessary) |
 
-The interval can also be changed while the Morse identification is being transmitted. The new value is used for the silent phase that follows.
+A `TX` or `IDLE` change applies to the next window or silent phase; a `FOX` change applies to the next repeat of the identifier, so switching fox mid-transmission never corrupts the message in flight.
+
+Pressing `M` while transmitting is a quick way to yield the frequency without leaving Beacon: it cuts the identifier short, drops the carrier, and starts a full `IDLE` silence before the next burst. Pressing `M` during the silent phase simply restarts that countdown, so `M` always means "stay silent for the full `IDLE` time, starting now".
 
 ## Transmission protections
 
@@ -101,7 +151,9 @@ The following Fox Hunt / Beacon settings are stored in external flash:
 * attenuation level
 * staircase or signal-history gauge
 * audio mode
-* Beacon silent interval
+* fox identifier
+* Beacon `TX` window
+* Beacon `IDLE` interval
 
 Changes are saved automatically and restored the next time the feature is opened. They are also included in an Air Copy `Settings` transfer. A full factory reset clears them.
 
@@ -112,4 +164,3 @@ Changes are saved automatically and restored the next time the feature is opened
 * [Programming with CHIRP](./Programming-with-CHIRP)
 * [Radio operation](./Radio-operation)
 * [Menu](./Menu)
-