Fine Tuning the Pre-Amplifier

[foxhunter]

Setting the gain properly is very often try&error

It heavily depends on the area and the possible obstacles including frequencies around you.
A good starting point is installing the graphs1090 of @wiedehopf he provides on his Github page.
Then change the gain for one day and compare the results.
You should also check on heywhatsthat.com your max. possible range

There are also some great threads in this forum with plenty of information. e.g.

Thoughts on optimizing gain

The topic of gain comes up often enough and unlike some i don’t like the gain optimization script. Aircraft fading in and out of view make short term number gathering not that useful. The metric i like most for optimizing gain is the percentage of what dump1090 calls “strong_signals”. Those “strong_signals” are messages that get close to getting clipped. If you don’t care about some background you can scroll down to the next post for the HOWTO This is a clipped signal, the wa…

For Beginners - How to Set / Change Gain

Most likely you won’t get good range anyway because of the buildings. It might be beneficial to reduce gain quite a bit further if you want to receive all the close-in signals. See this thread for some advice on the topic: Thoughts on optimizing gain - #2 by wiedehopf (the first post of the linked thread is some more explanation on the topic)