Update README.md Autogain Section (#135)

Updated autogain section to reflect correct default values as presented in the following files:

- rootfs/usr/local/bin/autogain978
- rootfs/scripts/autogain.sh

Co-authored-by: kx1t <[email protected]>

README.md

@@ -347,13 +347,13 @@ These variables control the autogain system (explained further below). These sho
 
 | Variable | Description | Default |
 |----------|-------------|---------|
-| `DUMP978_AUTOGAIN_INITIAL_TIMEPERIOD` | How long the autogain initialization phase should take (ie: "roughing in"), in seconds. | `21600` (6 hours) |
-| `DUMP978_AUTOGAIN_INITIAL_INTERVAL` | How often autogain should measure and adjust the gain during the initialization phase, in seconds. | `600` (10 minutes) |
+| `DUMP978_AUTOGAIN_INITIAL_TIMEPERIOD` | How long the autogain initialization phase should take (ie: "roughing in"), in seconds. | `32400` (9 hours) |
+| `DUMP978_AUTOGAIN_INITIAL_INTERVAL` | How often autogain should measure and adjust the gain during the initialization phase, in seconds. | `900` (15 minutes) |
 | `DUMP978_AUTOGAIN_SUBSEQUENT_INTERVAL` | How often autogain should measure and adjust the gain after the initialization phase is done, in seconds. | `84600` (24 hours) |
 | `DUMP978_AUTOGAIN_ADJUSTMENT_LIMITS` | If set to `true`/`on`/`yes`/`1`, while in the initialization phase, autogain will only adjust the gain during the timeframe set by the `DUMP978_AUTOGAIN_ADJUSTMENT_TIMEFRAME` parameter. | `true` |
 | `DUMP978_AUTOGAIN_ADJUSTMENT_TIMEFRAME` | Timeframe limits for autogain during the initializaion phase, in `HHMM-HHMM` (start hours/minutes to end hours/minutes). If an adjustment "run" falls outside these limits, the autogain adjustment is delayed until the start of the next timeframe. Times are based on the container's Timezone (`TZ`) setting. | `0900-1800` (9 AM - 6 PM, local container time) |
-| `DUMP978_AUTOGAIN_LOW_PCT` | If the percentage of "strong signals" (>3dB) over a measuring period is less than this parameter, the gain will be increased by 1 position | `2.5` (2.5%) |
-| `DUMP978_AUTOGAIN_HIGH_PCT` | If the percentage of "strong signals" (>3dB) over a measuring period is more than this parameter, the gain will be decreased by 1 position | `6.0` (6.0%) |
+| `DUMP978_AUTOGAIN_LOW_PCT` | If the percentage of "strong signals" (>3.5dB) over a measuring period is less than this parameter, the gain will be increased by 1 position | `5.0` (5.0%) |
+| `DUMP978_AUTOGAIN_HIGH_PCT` | If the percentage of "strong signals" (>3.5dB) over a measuring period is more than this parameter, the gain will be decreased by 1 position | `10.0` (10.0%) |
 | `READSB_AUTOGAIN_MIN_SAMPLES` | Minimum number of received samples for autogain to be able to consider adjusting the gain | `1000` |
 | `READSB_AUTOGAIN_USE_RAW` |  If set to `true`/`on`/`yes`/`1`, the autogain function will use the "raw" message count rather than the "accepted" message count. | `true` |
 | `SUBSEQUENT_INTERVAL_MINIMUM_COMPLETION_PCT` | Minimum percentage of `DUMP978_AUTOGAIN_SUBSEQUENT_INTERVAL` time that needs to be completed before autogain will use the collected data during the subsequent/long-term process | `50` |
@@ -362,12 +362,12 @@ These variables control the autogain system (explained further below). These sho
 
 An automatic gain adjustment system is included in this container, and can be activated by setting the environment variable `DUMP978_SDR_GAIN` to `autogain`. You should also map `/var/globe_history/` to persistent storage, otherwise the autogain system will start over each time the container is restarted.
 
-Autogain will take several hours to initially work out a reasonable gain. This is the so-called "initialization period", which is by default 6 hours. It will then perform a daily measurement to see if your gain needs further adjusting.
+Autogain will take several hours to initially work out a reasonable gain. This is the so-called "initialization period", which is by default 9 hours. It will then perform a daily measurement to see if your gain needs further adjusting.
 
 The autogain system will work as follows; values are based on the default parameter settings from above:
 
 1. `dump978` is set to maximum gain.
-2. Initial results are collected every 10 minutes, for up to 6 hours (initialization phase). If `DUMP978_AUTOGAIN_ADJUSTMENT_LIMITS` is set to true, measurements are suspended if the time is outside the set time limits (0900 - 1800 local container time). Every 10 minutes, the gain is adjusted by 1 position if the average percentage of "strong" signals (>-3dB) is less than 2.5% or more than 6.0%.
+2. Initial results are collected every 15 minutes, for up to 9 hours (initialization phase). If `DUMP978_AUTOGAIN_ADJUSTMENT_LIMITS` is set to true, measurements are suspended if the time is outside the set time limits (0900 - 1800 local container time). Every 15 minutes, the gain is adjusted by 1 position if the average percentage of "strong" signals (>-3.5dB) is less than 5.0% or more than 10.0%.
 3. After the initialization phase is over, the average percentage of "strong signal" is calculated on a daily basis, and an adjustment is made accordingly.
 
 ### Forcing autogain to re-run from scratch