# Optimizing Gain **URL:** \ **Category:** ADS-B Flight Tracking\ **Created:** [June 1, 2020, 1:27pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561 "2020-06-01T13:27:11Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![anandks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/anandks/32/131694_2.png) [@anandks](https://discussions.flightaware.com/u/anandks)\ **Post date:** [June 1, 2020, 1:27pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/1 "2020-06-01T13:27:12Z")
Hi all: I have been playing with some scripts that were posted here in the forums, I would like to see for some more help in figuring out how many of you are running your feeders. I understand, no two feeders are alike, but there has to be some rule of thumb and pitfalls to watch out for. based on the scripts results, I settled on running the Prostick Plus on gain of 28 or 29.7 and I am getting the following ![dump1090-localhost-signal-24h](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/e/d/ede8624a0e710aa416d15c872b311a5392a45271.png) ![dump1090-localhost-local_trailing_rate-24h](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/a/8/a827e5235675daf91ca7b0735e996682fb63088b.png) ![dump1090-localhost-range-24h](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/b/4/b4494afa71409aff56e63a58740a4e5afb1b0352.png) Given that the noise floor seems to be lower , I would have thought my range would be pushing to the limits of the horizon, but seems to drop off well before that. Edited info below: 280’ AGL, ANT220K discone, 7/8 Heliax Discone is what I have access to - The feedline is terminated into a Minicircuits splitter ZESC-2-11+, one port feeds into a Minicircuits VBFZ-1065+ filter prior to going into ProStick Plus. without the filter, there is front end overload. The other port is a second RTL, I have been experimenting with UAT ---
**Author:** ![geckoVN](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/geckovn/32/136508_2.png) [@geckoVN](https://discussions.flightaware.com/u/geckoVN)\ **Post date:** [June 1, 2020, 2:03pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/2 "2020-06-01T14:03:54Z")
Usual set of questions: How high is your antenna? How obscured is your horizon? Knowing nothing of your location, I plotted your coordinates and got a predicted range of about 200 miles. ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/0/6/065324409fd5a355bc865ca9a8f3c6bf6400ce23.png) ---
**Author:** ![wiedehopf](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/wiedehopf/32/114045_2.png) [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)\ **Post date:** [June 1, 2020, 2:05pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/3 "2020-06-01T14:05:06Z")
[Thoughts on optimizing gain](https://discussions.flightaware.com/t/thoughts-on-optimizing-gain/44482) Gain seems a bit low. Also the noise floor you see is after the gain of the SDR, so it’s not an absolute thing. As only the SNR matters … well a low noise floor after reducing the gain a bunch doesn’t really give you anything. If you have the antenna in clear view of the horizon and would expect more due to your terrain, think about how lossy your coax is and maybe also consider a filter. Terrain limited reception: [GitHub - wiedehopf/tar1090: Provides an improved webinterface for use with ADS-B decoders readsb / dump1090-fa](https://github.com/wiedehopf/tar1090#heywhatsthatcom-range-outline) ---
**Author:** ![anandks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/anandks/32/131694_2.png) [@anandks](https://discussions.flightaware.com/u/anandks)\ **Post date:** [June 1, 2020, 2:12pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/4 "2020-06-01T14:12:33Z")
280’ AGL, ANT220K discone, 7/8 Heliax heywahtsthat range rings about 250nm ![download](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/2/b/2bf8fcc03734a853ac597012c56c68cd9e7b15d1.jpeg) ---
**Author:** ![geckoVN](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/geckovn/32/136508_2.png) [@geckoVN](https://discussions.flightaware.com/u/geckoVN)\ **Post date:** [June 1, 2020, 2:17pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/5 "2020-06-01T14:17:55Z")
> [@anandks](#): > > 280’ AGL, ANT220K discone, 7/8 Heliax Great height, fantastic coax, but the antenna … not so good. If you must run a discone, you’ll need a filter - it is after all designed to pick up everything. ---
**Author:** ![anandks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/anandks/32/131694_2.png) [@anandks](https://discussions.flightaware.com/u/anandks)\ **Post date:** [June 1, 2020, 2:29pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/6 "2020-06-01T14:29:57Z")
sorry , yes I thought I include this in my OP. Discone is what I have access to - The feedline is terminated into a Minicircuits splitter ZESC-2-11+, one port feeds into a Minicircuits VBFZ-1065+ filter prior to going into ProStick Plus. without the filter, there is front end overload. The other port is a second RTL, I have been experimenting with UAT ---
**Author:** ![technodevotee](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/technodevotee/32/136901_2.png) [@technodevotee](https://discussions.flightaware.com/u/technodevotee)\ **Post date:** [June 1, 2020, 6:26pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/7 "2020-06-01T18:26:11Z")
That seems like an awful lot of insertion loss between the receiver and the antenna to me, especially given that the antenna is a discone. ---
**Author:** ![LawrenceHill](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/lawrencehill/32/113365_2.png) [@LawrenceHill](https://discussions.flightaware.com/u/LawrenceHill)\ **Post date:** [June 1, 2020, 6:48pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/8 "2020-06-01T18:48:11Z")
> [@anandks](#): > > one port feeds into a Minicircuits VBFZ-1065+ filter I think you need a better filter. That one is much too wideband and is only giving about 4dB of rejection at GSM frequencies. ---
**Author:** ![anandks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/anandks/32/131694_2.png) [@anandks](https://discussions.flightaware.com/u/anandks)\ **Post date:** [June 1, 2020, 8:12pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/9 "2020-06-01T20:12:28Z")
ok, I would have thought, the internal filter would be narrow enough to suppress the gsm channels. I guess it doesnt ---
**Author:** ![LawrenceHill](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/lawrencehill/32/113365_2.png) [@LawrenceHill](https://discussions.flightaware.com/u/LawrenceHill)\ **Post date:** [June 1, 2020, 8:32pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/10 "2020-06-01T20:32:07Z")
> [@anandks](#): > > I would have thought, the internal filter would be narrow enough The problem is, with large levels of gsm signals, you can overload the amplifier that is in front of that filter. ---
**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 1, 2020, 8:50pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/11 "2020-06-01T20:50:23Z")
  # [RF Scan of Various Combinations of Dongles, Filter, and LNA](https://discussions.flightaware.com/t/rf-scan-of-various-combinations-of-dongles-filter-and-lna/59442)   ---
**Author:** ![anandks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/anandks/32/131694_2.png) [@anandks](https://discussions.flightaware.com/u/anandks)\ **Post date:** [June 15, 2020, 7:14pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/12 "2020-06-15T19:14:54Z")
been testing out various gain settings, and options, including combination of filters, amps and splitters. so, far I can claim - that I am getting closer. have almost tripled the # of crafts tracked and expanded the range by an additional 130nm ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/5/7/57f084cd9f5552d313e4f8a798bd3ef621289bf5.png) ![image](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/8/8/88e0db296060f2e687f5b2f06ee52ed8b905b874.png) ---
**Author:** ![system](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/system/32/38558_2.png) [@system](https://discussions.flightaware.com/u/system)\ **Post date:** [June 15, 2021, 7:14pm UTC](https://discussions.flightaware.com/t/optimizing-gain/65561/13 "2021-06-15T19:14:55Z")
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