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  • abcd567
    replied
    Originally posted by magnum View Post
    There is potentially too much noise around you. Having an LNA with this range increases also the noise where then the ADS-B signals are hidden behind it.
    Reducing gain can help a bit, but a filter optimized to 1090 Mhz would be better

    Do I need a Filter? - Find RF Signals In Area


    .

    Leave a comment:


  • magnum
    replied
    Originally posted by matysldn View Post
    Has any of you used this LNA? range from 0.1 to 2000 MHz sounds great. I just instaled it but I can see a sudden drop from eg. 100 planes to only 30 and messages from 400 to almost 0. Ive tried with different power supply from 5v to 12v and doesn't make any difference. Any thoughts?

    [ATTACH=CONFIG]11215[/ATTACH]
    There is potentially too much noise around you. Having an LNA with this range increases also the noise where then the ADS-B signals are hidden behind it.
    Reducing gain can help a bit, but a filter optimized to 1090 Mhz would be better

    Leave a comment:


  • wiedehopf
    replied
    There is a reason they built a triple-filtered LNA for ADS-B: https://www.rtl-sdr.com/new-product-...mhz-ads-b-lna/

    The reason is: broadband amplifiers don't work well for ADS-B unless you have your own filters to go with it and even then the above product i likely superior.

    Leave a comment:


  • abcd567
    replied
    Too much gain can also cause this. Reduce gain of dump1090 to 20 dB and see if it improves.

    Leave a comment:


  • petercr
    replied
    Amplification range is too broad and if you have any local interference (eg local GSM towers) it will more than likely make the situation worse. Dropping plane count and messages that low seems to suggest that maybe the amplifier itself is faulty or there's a bad connector on the pcb (it can happen).

    Leave a comment:


  • matysldn
    replied
    Has any of you used this LNA? range from 0.1 to 2000 MHz sounds great. I just instaled it but I can see a sudden drop from eg. 100 planes to only 30 and messages from 400 to almost 0. Ive tried with different power supply from 5v to 12v and doesn't make any difference. Any thoughts?

    LNA.jpg

    Leave a comment:


  • abcd567
    replied
    Dark blue (1090 mhz) will remove both GSM800 and GSM900

    https://discussions.flightaware.com/...s-filter/45287

    .

    Leave a comment:


  • IZ8292SWL
    replied
    Originally posted by abcd567 View Post
    I cannot read frequencies on your scan (scan image too small on my phone).
    If the interfereing signal is around 900 ~950 Mhz, then you have to use FA's dark blue one. (1090 mhz only). The light blue one (978+1090) will not remove 900~950 mhz interference
    I have both interference from 800 and 900 mhz!

    Leave a comment:


  • abcd567
    replied
    I cannot read frequencies on your scan (scan image too small on my phone).
    If the interfereing signal is around 900 ~950 Mhz, then you have to use FA's dark blue one. (1090 mhz only). The light blue one (978+1090) will not remove 900~950 mhz interference

    Leave a comment:


  • IZ8292SWL
    replied
    Yes, i suppose....
    Pretty strong GSM signal isn't it?
    Do you think that the Flightaware filter will do the trick?

    Leave a comment:


  • abcd567
    replied
    Originally posted by IZ8292SWL View Post
    So this afternoon i ran the test that i found in a Flightaware forum post

    You dont have to go to flightaware to find this how-to. I have posted the how-to in both Flightaware and Flightradar24 forums

    Do I need a Filter? - Find RF Signals In Area



    Originally posted by IZ8292SWL View Post

    and those are the results:
    [ATTACH=CONFIG]11197[/ATTACH]

    This test is coming from another USB stick that currently is in a box on the roof.
    I left it there in order to analyze this situation...

    I'm using the Flightaware PRO stick.
    Alone it can't stop all the QRM coming from the GSM cell towers.

    I suppose i have to buy a filter in order to use my antenna on the roof!!
    What do you think?
    GSM800.jpg

    GSM900.jpg.

    You have cell interference in both GSM800 and GSM900.
    Even if you use flightaware blue stick, the filter in it is after the LNA, so the filter will save the tuner from overload by these signals, but LNA will still get overloaded. You may need another filter between antenna and flightaware blue stick.
    Last edited by abcd567; 2019-10-17, 21:50.

    Leave a comment:


  • IZ8292SWL
    replied
    Hi @abcd567 and thanks for all your tips.
    Today i tried to move the antenna on the roof.
    I had to set the gain settings to about 28 db because, i suppose, i have a very bad GSM signal interference.
    Result were worse than the setup on my balcony.
    I also tried to listen to some airband frequencies and they were pretty noisy and a lot of QRM.
    On my balcony, i can clearly ear the ATIS but not on top of my building, even with a FM bandstop filter attached....
    So this afternoon i ran the test that i found in a Flightaware forum post and those are the results:
    scan.jpg

    This test is coming from another USB stick that currently is in a box on the roof.
    I left it there in order to analyze this situation...

    I'm using the Flightaware PRO stick.
    Alone it can't stop all the QRM coming from the GSM cell towers.

    I suppose i have to buy a filter in order to use my antenna on the roof!!
    What do you think?
    Cheers!
    Last edited by IZ8292SWL; 2019-10-17, 21:13.

    Leave a comment:


  • abcd567
    replied
    IZ8292SWL:

    Anybody used that grey pvc pipes?
    They look ok to put the cable inside and leave only the spider outside on top.
    It will be OK as the spider itself is outside the pipe, hence the grey pipe's RF attenuation wont affect the performance of Spider.

    Spider by jploch.jpg

    Leave a comment:


  • IZ8292SWL
    replied
    Hi! I updated my antenna with a foam covered spider (the one @abcd567 showed above).
    I also bought a blue Flightaware stick.
    Well, this setup made a huuuuge improvement over the one i used so far (a simple generic stick and a modded whip antenna, the one you have to cut to match the frequency).

    This little antenna was a real suriprise
    150-180 messages per second and almost a doubled range over the old setup.
    I guess the final step is to put the spidy on the roof. Currently is outside on the balcony as the previous one.
    Anybody used that grey pvc pipes?
    They look ok to put the cable inside and leave only the spider outside on top.

    tubo-pvc-filett-barra-da-6mt-pn-16-d1-1-2-.jpg
    Last edited by IZ8292SWL; 2019-10-16, 19:53.

    Leave a comment:


  • abcd567
    replied
    IZ8292SWL:

    If you mean this one, it works equally good.

    QuickSpider-Ver1.jpg

    https://forum.flightradar24.com/thre...-or-N-Conector

    It was my first version of Quick Spider dated 2015. Later I noticed people are so accustomed to bare copper radials and whip, they took it as a toy, and it was mostly rejected.

    Therefore I released next version in which whip's & radial's insulation was peeled off, and this design was accepted immediately
    Last edited by abcd567; 2019-10-15, 09:05.

    Leave a comment:

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