# Optimising Gain

**URL:** <https://discussions.flightaware.com/t/optimising-gain/93240>\
**Category:** ADS-B Flight Tracking\
**Created:** [June 14, 2024, 2:26pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240 "2024-06-14T14:26:31Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 14, 2024, 2:26pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/1 "2024-06-14T14:26:31Z")

</div>

Presently piaware 6.1 running on Pi 3b+ buster is set with AGC on results in approx 11-14% of messages \> -3dbfs

I ran optimize-gain.py and got the following results  
Not sure whether to leave on AGC - appears to have gain at 49.6  
If not which gain setting would be best - it’s rather confusing

TIA

| test 1 of 5 | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| gain= | 49.60 | messages= | 54,661 | positions= | 2,746 | planes= | 57 |
| gain= | 48.00 | messages= | 52,748 | positions= | 2,590 | planes= | 59 |
| gain= | 44.50 | messages= | 48,169 | positions= | 2,308 | planes= | 56 |
| gain= | 43.90 | messages= | 49,875 | positions= | 2,451 | planes= | 57 |
| gain= | 43.40 | messages= | 46,902 | positions= | 2,318 | planes= | 59 |
| gain= | 42.10 | messages= | 46,433 | positions= | 2,287 | planes= | 52 |
| gain= | 40.20 | messages= | 46,175 | positions= | 2,288 | planes= | 52 |
| gain= | 38.60 | messages= | 43,013 | positions= | 2,259 | planes= | 49 |
| gain= | 37.20 | messages= | 44,168 | positions= | 2,307 | planes= | 49 |
| gain= | 36.40 | messages= | 46,145 | positions= | 2,257 | planes= | 46 |
| gain= | 33.80 | messages= | 42,327 | positions= | 2,018 | planes= | 48 |
| gain= | 32.80 | messages= | 39,686 | positions= | 2,034 | planes= | 50 |
| gain= | 29.70 | messages= | 42,365 | positions= | 2,284 | planes= | 49 |
| gain= | 28.00 | messages= | 46,034 | positions= | 2,496 | planes= | 45 |
| gain= | 25.40 | messages= | 42,605 | positions= | 2,274 | planes= | 45 |
| gain= | 22.90 | messages= | 39,285 | positions= | 2,144 | planes= | 44 |
| gain= | 20.70 | messages= | 38,644 | positions= | 2,119 | planes= | 51 |
| test | 2 of | 5 | | | | | |
| gain= | 49.60 | messages= | 41,193 | positions= | 2,252 | planes= | 51 |
| gain= | 48.00 | messages= | 42,596 | positions= | 2,235 | planes= | 54 |
| gain= | 44.50 | messages= | 42,345 | positions= | 2,113 | planes= | 52 |
| gain= | 43.90 | messages= | 41,633 | positions= | 2,045 | planes= | 52 |
| gain= | 43.40 | messages= | 41,603 | positions= | 2,230 | planes= | 55 |
| gain= | 42.10 | messages= | 42,987 | positions= | 2,273 | planes= | 56 |
| gain= | 40.20 | messages= | 45,086 | positions= | 2,481 | planes= | 52 |
| gain= | 38.60 | messages= | 46,126 | positions= | 2,553 | planes= | 53 |
| gain= | 37.20 | messages= | 50,541 | positions= | 2,843 | planes= | 55 |
| gain= | 36.40 | messages= | 50,039 | positions= | 2,806 | planes= | 55 |
| gain= | 33.80 | messages= | 48,125 | positions= | 2,788 | planes= | 58 |
| gain= | 32.80 | messages= | 47,244 | positions= | 2,676 | planes= | 55 |
| gain= | 29.70 | messages= | 49,429 | positions= | 2,839 | planes= | 61 |
| gain= | 28.00 | messages= | 50,832 | positions= | 2,823 | planes= | 61 |
| gain= | 25.40 | messages= | 53,873 | positions= | 2,949 | planes= | 61 |
| gain= | 22.90 | messages= | 56,442 | positions= | 3,150 | planes= | 57 |
| gain= | 20.70 | messages= | 53,847 | positions= | 2,926 | planes= | 61 |
| test | 3 of | 5 | | | | | |
| gain= | 49.60 | messages= | 55,600 | positions= | 2,904 | planes= | 64 |
| gain= | 48.00 | messages= | 55,856 | positions= | 2,915 | planes= | 68 |
| gain= | 44.50 | messages= | 58,439 | positions= | 2,980 | planes= | 70 |
| gain= | 43.90 | messages= | 59,170 | positions= | 3,073 | planes= | 73 |
| gain= | 43.40 | messages= | 57,225 | positions= | 2,883 | planes= | 73 |
| gain= | 42.10 | messages= | 59,060 | positions= | 2,959 | planes= | 76 |
| gain= | 40.20 | messages= | 59,550 | positions= | 2,943 | planes= | 80 |
| gain= | 38.60 | messages= | 62,489 | positions= | 3,105 | planes= | 76 |
| gain= | 37.20 | messages= | 58,711 | positions= | 2,862 | planes= | 78 |
| gain= | 36.40 | messages= | 60,633 | positions= | 2,989 | planes= | 76 |
| gain= | 33.80 | messages= | 62,804 | positions= | 3,111 | planes= | 76 |
| gain= | 32.80 | messages= | 65,260 | positions= | 3,406 | planes= | 80 |
| gain= | 29.70 | messages= | 65,811 | positions= | 3,423 | planes= | 78 |
| gain= | 28.00 | messages= | 64,502 | positions= | 3,312 | planes= | 73 |
| gain= | 25.40 | messages= | 65,806 | positions= | 3,343 | planes= | 72 |
| gain= | 22.90 | messages= | 65,192 | positions= | 3,313 | planes= | 64 |
| gain= | 20.70 | messages= | 61,706 | positions= | 3,135 | planes= | 62 |
| test | 4 of | 5 | | | | | |
| gain= | 49.60 | messages= | 60,285 | positions= | 3,147 | planes= | 71 |
| gain= | 48.00 | messages= | 59,860 | positions= | 3,094 | planes= | 68 |
| gain= | 44.50 | messages= | 59,108 | positions= | 3,122 | planes= | 74 |
| gain= | 43.90 | messages= | 62,337 | positions= | 3,213 | planes= | 65 |
| gain= | 43.40 | messages= | 61,017 | positions= | 3,087 | planes= | 66 |
| gain= | 42.10 | messages= | 60,478 | positions= | 3,157 | planes= | 66 |
| gain= | 40.20 | messages= | 62,396 | positions= | 3,151 | planes= | 69 |
| gain= | 38.60 | messages= | 61,857 | positions= | 3,240 | planes= | 68 |
| gain= | 37.20 | messages= | 58,730 | positions= | 3,093 | planes= | 65 |
| gain= | 36.40 | messages= | 58,454 | positions= | 3,135 | planes= | 64 |
| gain= | 33.80 | messages= | 57,823 | positions= | 3,091 | planes= | 69 |
| gain= | 32.80 | messages= | 58,009 | positions= | 3,198 | planes= | 68 |
| gain= | 29.70 | messages= | 53,719 | positions= | 2,902 | planes= | 61 |
| gain= | 28.00 | messages= | 54,794 | positions= | 2,944 | planes= | 60 |
| gain= | 25.40 | messages= | 54,796 | positions= | 2,876 | planes= | 57 |
| gain= | 22.90 | messages= | 54,243 | positions= | 2,765 | planes= | 64 |
| gain= | 20.70 | messages= | 53,466 | positions= | 2,706 | planes= | 59 |
| test | 5 of | 5 | | | | | |
| gain= | 49.60 | messages= | 54,462 | positions= | 2,745 | planes= | 67 |
| gain= | 48.00 | messages= | 53,028 | positions= | 2,758 | planes= | 66 |
| gain= | 44.50 | messages= | 52,630 | positions= | 2,766 | planes= | 68 |
| gain= | 43.90 | messages= | 54,776 | positions= | 2,805 | planes= | 64 |
| gain= | 43.40 | messages= | 53,891 | positions= | 2,735 | planes= | 65 |
| gain= | 42.10 | messages= | 57,845 | positions= | 2,864 | planes= | 67 |
| gain= | 40.20 | messages= | 60,469 | positions= | 3,167 | planes= | 68 |
| gain= | 38.60 | messages= | 60,304 | positions= | 3,007 | planes= | 68 |
| gain= | 37.20 | messages= | 58,741 | positions= | 2,988 | planes= | 66 |
| gain= | 36.40 | messages= | 56,910 | positions= | 3,057 | planes= | 64 |
| gain= | 33.80 | messages= | 57,049 | positions= | 2,975 | planes= | 69 |
| gain= | 32.80 | messages= | 56,665 | positions= | 2,912 | planes= | 62 |
| gain= | 29.70 | messages= | 54,026 | positions= | 2,760 | planes= | 61 |
| gain= | 28.00 | messages= | 55,041 | positions= | 2,779 | planes= | 56 |
| gain= | 25.40 | messages= | 50,043 | positions= | 2,575 | planes= | 56 |
| gain= | 22.90 | messages= | 45,426 | positions= | 2,270 | planes= | 54 |
| gain= | 20.70 | messages= | 39,123 | positions= | 1,948 | planes= | 53 |
| | | | | | | | |
| ===Totals=== | | | | | | | |
| Gain, Messages, Positions, Aircraft | | | | | | | |
| 49.6 | 266,201 | 13,794 | 266 | | | | |
| 48.0 | 264,088 | 13,592 | 266 | | | | |
| 44.5 | 260,691 | 13,289 | 272 | | | | |
| 43.9 | 267,791 | 13,587 | 269 | | | | |
| 43.4 | 260,638 | 13,253 | 270 | | | | |
| 42.1 | 266,803 | 13,540 | 272 | | | | |
| 40.2 | 273,676 | 14,030 | 267 | | | | |
| 38.6 | 273,789 | 14,164 | 260 | | | | |
| 37.2 | 270,891 | 14,093 | 262 | | | | |
| 36.4 | 272,181 | 14,244 | 250 | | | | |
| 33.8 | 268,128 | 13,983 | 259 | | | | |
| 32.8 | 266,864 | 14,226 | 255 | | | | |
| 29.7 | 265,350 | 14,208 | 253 | | | | |
| 28.0 | 271,203 | 14,354 | 246 | | | | |
| 25.4 | 267,123 | 14,017 | 252 | | | | |
| 22.9 | 260,588 | 13,642 | 245 | | | | |
| 20.7 | 246,786 | 12,834 | 250 | | | | |

Jun 14 13:45:22 piaware dump1090-fa[30797]: adaptive: available dynamic range (33.7dB) \>= required dynamic range (30.0dB), continuing upw  
Jun 14 13:45:22 piaware dump1090-fa[30797]: adaptive: changing gain from 48.0dB (step 27) to 49.6dB (step 28) because: probing dynamic ra  
Jun 14 13:45:22 piaware dump1090-fa[30797]: rtlsdr: tuner gain set to 49.6 dB (gain step 28)  
Jun 14 13:45:32 piaware dump1090-fa[30797]: adaptive: available dynamic range (33.6dB) \>= required dynamic range (30.0dB), continuing upwJun 14 13:45:32 piaware dump1090-fa[30797]: adaptive: changing gain from 49.6dB (step 28) to 58.6dB (step 29) because: probing dynamic raJun 14 13:45:32 piaware dump1090-fa[30797]: rtlsdr: tuner gain set to about 58.6 dB (gain step 29) (tuner AGC enabled)  
Jun 14 13:45:42 piaware dump1090-fa[30797]: adaptive: available dynamic range (23.3dB) \< required dynamic range (30.0dB), switching to do  
Jun 14 13:45:42 piaware dump1090-fa[30797]: adaptive: changing gain from 58.6dB (step 29) to 49.6dB (step 28) because: probing dynamic ra  
Jun 14 13:45:42 piaware dump1090-fa[30797]: rtlsdr: tuner gain set to 49.6 dB (gain step 28)  
Jun 14 13:45:52 piaware dump1090-fa[30797]: adaptive: available dynamic range (33.3dB) \>= required dynamic range (30.0dB), stopping downw

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<div class="post-metadata">

**Author:** ![CraigWoodThomas](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/craigwoodthomas/32/121258_2.png) [@CraigWoodThomas](https://discussions.flightaware.com/u/CraigWoodThomas)\
**Post date:** [June 14, 2024, 2:53pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/2 "2024-06-14T14:53:18Z")

</div>

I don’t like AGC controlling my gain. I am in central florida and have the luxury of flat terrain surrounding me with some nearby tall oaks that are out of my control. My Vinnant antenna is 35 foot above ground level and above the peak of my single story ranch style house. I run a fixed gain of 43.9 and it keeps me within the 5% messages threshold that is advised. Everyone is different but maybe that could be a starting point for you with a fixed gain setting.

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<div class="post-metadata">

**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\
**Post date:** [June 14, 2024, 4:10pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/3 "2024-06-14T16:10:35Z")

</div>

> [@jhgreene](#):
>
> I ran optimize-gain.py

It is hard to get any conclusive gain setting using optimize-gain.py.  
This script was created several years ago, and subsequently updated, as an initial attempt to find optimum gain.

I have stopped using this script since several years. After quitting use of this script, I resorted to manually best setting by trial-and-error. I will set gain to 49.6 and leave it there for a day or two, then from graphs1090, note the plane count, message rate, and messages \> -3 dBFS. Next reduce gain to 46, and repeat above excercise. Kept on reducing gain in steps of say 3 dB, till I could find the best setting.

Recently, I have started using “Adaptive Gain” setting given in file `/etc/default/dump1090-fa. I am very satisfied with the results. Please see screenshots below.

&nbsp;

![dump1090-localhost-misc-24h](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/5/8/585784c9f9df92adff0ce6aebe1845cb3c6d43de.png)

&nbsp;

 ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/e/1/e1b199197b441be49c098e3387ecbc77a277679b.png)

&nbs;

 ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/0/0/00f7b0a2418710e45d7595aabb9acba3d7e1083e.png)

&nbsp;

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 16, 2024, 9:02pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/4 "2024-06-16T21:02:24Z")

</div>

applied advised settings re adaptive gain. results in 13.3 % of messages \> - 3dbfs…

 ![Screenshot_20240616_215551_com.opera.browser](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/e/b/eb407d4bb201e722168fdc6def3417929c040539.jpeg)  
should I leave as per your image or make further changes. trying maximise feed contribution. TIA

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<div class="post-metadata">

**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\
**Post date:** [June 16, 2024, 9:24pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/5 "2024-06-16T21:24:40Z")

</div>

> [@jhgreene](#):
>
> applied advised settings re adaptive gain. results in 13.3 % of messages \> - 3dbfs…

The screenshot of your graph was taken how many hours after making changes & restarting dump1090-fa?

You have to wait for at least 24 hrs after making changes and restarting dump1090-fa. Then only graph will show the affect of the changes.

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 17, 2024, 6:24pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/6 "2024-06-17T18:24:03Z")

</div>

left it another 20+ hours now down to 12.5%…

 ![Screenshot_20240617_191937_com.opera.browser](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/f/7/f774a8fbfc3038f1388aba0dccff23a35255e9ae.jpeg)

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<div class="post-metadata">

**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\
**Post date:** [June 17, 2024, 6:57pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/7 "2024-06-17T18:57:30Z")

</div>

> [@jhgreene](#):
>
> left it another 20+ hours now down to 12.5%…

**(1) Reduce Maximum gain to 49.6.**  
The method depends on which image you are using (Piaware SD Card or Raspberry Pi OS?)

(1-a) If using **Raspberry Pi OS image** , edit file /etc/default/dump1090-fa, and change:  
`ADAPTIVE_MAX_GAIN= `  
TO  
`ADAPTIVE_MAX_GAIN=49.6`

Save file after making above changes, then restat dump1090-fa

`sudo systemctl restart dump1090-fa `

(1-b) If using **piaware sd card image** issue following commands:

`sudo piaware-config adaptive-max-gain 49.6 `

`sudo reboot `

&nbsp;

**(2) Please post screenshot of graph “Misc”.**  
Mine is given below for your reference.

![dump1090-localhost-misc-24h](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/2/5/25c5f4e275b4b9de86ff937de397cbf675fc0699.png)

&nbsp;

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 17, 2024, 7:44pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/8 "2024-06-17T19:44:09Z")

</div>

am using piaware sd image. Will apply change as advised and post upgated graph in 24 hours. I only updated your graphs app today so only have last few hours in misc

 ![Screenshot_20240617_204053_com.opera.browser](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/d/b/dbbf5753160e5ce0623bcd59aa2e9f1d92291ea6.jpeg)

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<div class="post-metadata">

**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\
**Post date:** [June 17, 2024, 9:26pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/9 "2024-06-17T21:26:57Z")

</div>

> [@jhgreene](#):
>
> I only updated **your** graphs app today

This is not my graphs app, it is @wiedehopf’s graph app.

&nbsp;

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 17, 2024, 10:30pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/10 "2024-06-17T22:30:48Z")

</div>

oops apologies no offence meant. 😳

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 18, 2024, 6:09pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/11 "2024-06-18T18:09:40Z")

</div>

left it 20+hours now down to 11.4% pi was rebooted around 12 utc

 ![Screenshot_20240618_190518_com.opera.browser](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/e/f/ef1bdbc24973aa3faea1e6e588d16834f7ce6114.jpeg)  
 ![Screenshot_20240618_190538_com.opera.browser](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/f/9/f901f721057a1cf77e6583d9a09e10e07a5e5b2a.jpeg)

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 18, 2024, 8:44pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/12 "2024-06-18T20:44:06Z")

</div>

my adaptive gain wants to stay at the max…

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<div class="post-metadata">

**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\
**Post date:** [June 19, 2024, 12:05am UTC](https://discussions.flightaware.com/t/optimising-gain/93240/13 "2024-06-19T00:05:37Z")

</div>

> [@jhgreene](#):
>
> my adaptive gain wants to stay at the max

This normally happens when ADAPTIVE\_BURST is NOT set to yes

Check file `/etc/default/dump1090-fa`

&nbsp;

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 19, 2024, 1:04am UTC](https://discussions.flightaware.com/t/optimising-gain/93240/14 "2024-06-19T01:04:59Z")

</div>

🥴🥴🥴spot on. thought I had done that as instructed. Will report again in 24. Ty ty

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<div class="post-metadata">

**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\
**Post date:** [June 19, 2024, 2:59am UTC](https://discussions.flightaware.com/t/optimising-gain/93240/15 "2024-06-19T02:59:37Z")

</div>

> [@jhgreene](#):
>
> thought I had done that as instructed

Do you use vanila Raspberry Pi OS or Piaware SD card image?

If you are using piaware sd card image, then changes made to file `/etc/default/dump1090-fa` will disappear on reboot. In case of piaware sd card image, issue following commands:

`sudo piaware-config adaptive-burst yes `

`sudo reboot `

&nbsp;

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 19, 2024, 3:39am UTC](https://discussions.flightaware.com/t/optimising-gain/93240/16 "2024-06-19T03:39:38Z")

</div>

I use piaware sd card image. burst is now set. thank you. Will post new graphs in 24

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<div class="post-metadata">

**Author:** ![jhgreene](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jhgreene/32/121883_2.png) [@jhgreene](https://discussions.flightaware.com/u/jhgreene)\
**Post date:** [June 19, 2024, 7:07pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/17 "2024-06-19T19:07:56Z")

</div>

last 24 hours graphs below now down to 3.4% with gain auto set to 37.2. what do you think?

 ![Screenshot_20240619_200326_com.opera.browser](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/1/6/165d93b067e9746be86a5aa1b63f5ff156f11ddf.jpeg)  
 ![Screenshot_20240619_200353_com.opera.browser](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/3/6/36eeaff7995da8ee043d5e712265fe4b022443de.jpeg)

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**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\
**Post date:** [June 19, 2024, 10:48pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/18 "2024-06-19T22:48:21Z")

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> [@jhgreene](#):
>
> graphs below now down to 3.4% with gain auto set to 37.2. what do you think?

Messages \> -3 dBFS (3.3% of messages) is good.

If adaptive-gain is used, then the gain=37.2 or any other value (for example gain=60) is just the starting point. Once adaptive-gain starts controlling the gain, the gain=xxx setting has no impact.

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**Author:** ![jimMerk2](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jimmerk2/32/127232_2.png) [@jimMerk2](https://discussions.flightaware.com/u/jimMerk2)\
**Post date:** [June 20, 2024, 5:17pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/19 "2024-06-20T17:17:46Z")

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I found that using adaptive gain, the range was noticeably reduced. That was because the gain gets adjusted too far down (about 15 dB in my setup). But you can set an adaptive minimum gain in `/etc/default/dump1090-fa`. So I set that to 20 dB.  
`ADAPTIVE_MIN_GAIN=20`. I’m trying that now. May even need to be set a little higher.

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**Author:** ![Jsbird69](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jsbird69/32/135684_2.png) [@Jsbird69](https://discussions.flightaware.com/u/Jsbird69)\
**Post date:** [June 20, 2024, 9:32pm UTC](https://discussions.flightaware.com/t/optimising-gain/93240/20 "2024-06-20T21:32:02Z")

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I hope it’s OK if I jump into this thread, as ‘gain’ is currently on my plate.

On or about June 12, my gain jumped from 49.6 to something in the 50’s. It’s done this before, and then after a period of time, reverted back to 49.6.  
Here’s a 90 day look at that graph.  
 ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/c/7/c7b0317e193ce68dc94cc4f066b7ac598943a64b.png)  
When my gain increases like that, it causes the red area on this graph to go up to +30%,and I read recently that I want my red area below 3%.  
Here’s a 14 day look at that.

 ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/1/0/10df903c971932ee5775c9fe909091a2ecdbd634.png)

So, upon reading this thread today, I decided to give adaptive gain an audition. Here is the result after a few hours.  
 ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/b/c/bc36ac2e9e4a03aa4efab70d994d64fa99afac24.png)  
And my red area has gone way down, to less than 1%. Is that OK?

 ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/8/8/88f35ebc5fe7cc9f2e878dc9188b6c1b87c91e0c.png)

Thanks,

Jay

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