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Basic setup working well - next steps?

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  • abcd567
    replied
    Originally posted by JFreddieF View Post
    a Google search for "fr24 do I need a filter" should find it. The same info is also on the flightaware forums.
    Thanks for the information.

    By the way I dont need to Google to find it. I am the author of "Do I need a Filter" post, both on FR24 and Flightaware.


    https://forum.flightradar24.com/thre...ignals-In-Area


    https://discussions.flightaware.com/...a-filter/27833
    Last edited by abcd567; 2018-10-06, 13:18.

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  • JFreddieF
    replied
    Originally posted by ylis View Post
    I'd be interested in this !!
    I've set up a new thread in this section. I didn't give a step by step (I'm too lazy, sorry ). But I'm new to both ADSB and Linux, so if I can figure it out you might be able to as well! I'll try to add a bit more detail in the next few days.

    Leave a comment:


  • JFreddieF
    replied
    Filter effectiveness: There's a good description in one of the threads here - a Google search for "fr24 do I need a filter" should find it. The same info is also on the flightaware forums.

    EDIT:
    I'm using YOUR instructions, abcd567 !
    Last edited by JFreddieF; 2018-10-06, 13:14.

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  • ylis
    replied
    I've also set up a cron job to change the gain between day and night settings ... I haven't seen any discussions about doing this, I think it deserves it's own thread.
    I'd be interested in this !!

    Leave a comment:


  • abcd567
    replied
    Originally posted by JFreddieF View Post
    Even with the filter quite a bit of signal is present at 960 MHz
    This is true because 960 MHz is too close to 1090 MHz, and only a very narrow-band filter like Cavity or Ceramic effectively removes it.

    By the way how you determined that 960 MHz is not removed by the filters you have?

    Leave a comment:


  • abcd567
    replied
    Good work. It is very interesting to experiment with your hardware such as different dongles, amplifiers, filters, antennas and coax.

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  • JFreddieF
    replied
    So...after telling myself not to go and buy all the bits I could think off I did just that.

    First I added an LNA, then a week or so later I built a coax collinear antenna (6 elements).
    Both had positive effects: I've gone from a typical daily max range of 70 NM to 115 NM, sometimes seeing as far as 135. Apparently I have seen aircraft at 250 and 347 nm, but I have to assume that they were sending bad locations! Number of aircraft is much better too.

    The antenna and pigtail are made from RG174. Not ideal as it's fairly high loss, but it was cheap and available in a short (15m) reel. It's also a good size for SMA connectors. Part of my thinking was to avoid needing adapters for SMA to F- or N- type; both for the expense and the loss. Probably the wrong call on loss, but right for cost - and I have no other use for any leftover RF cable.

    I've also set up a cron job to change the gain between day and night settings - that has has a huge effect on both range and number of aircraft seen. I haven't seen any discussions about doing this, I think it deserves it's own thread.

    Next step: play with the antenna design a bit.

    Leave a comment:


  • JFreddieF
    started a topic Basic setup working well - next steps?

    Basic setup working well - next steps?

    Hi all,
    I got my first Pi and dongle just over a month ago. Thanks to wise words from this forum and others - and some experimenting - I think I've got it working as well as I can expect.

    I've got a few things in my local environment that I think are limiting what I can expect. I've got some ideas about next steps and I'd like to know what people think.

    Local issues:
    - Large building, a shopping centre (mall) within 75m
    - Mobile phone mast within 50m
    - Several airways nearby, and I'm midway between Heathrow and Luton so lots of aircraft at all heights.

    I'm running with the dongle and antenna shown on the build your own page (jet vision dongle and small antenna). I've got a SAW filter fitted. (I bought a flightaware filter first then realised the passband was too wide for the UK.) Even with the filter quite a bit of signal is present at 960 MHz, note it's a unenclosed PCB. I've managed to set the gain to give noise around -40 and peak signal around -3. I suspect it's being limited by both the phone signal and by high levels from aircraft overhead. Perhaps the bit depth is a factor too, but I plan to start another thread for that discussion.

    So, my thoughts. Do I:
    - Get a separate LNA (allow the dongle to run at lower gain)
    - Ditch the dongle and get a FlightAware Pro Stick Plus (as above, but neater and fewer connections)
    - Build Co-ax colinear antenna (lower gain overhead the site)

    I'm leaning towards that latter because it's more fun, but I suspect the new dongle would give the best improvement.

    All thoughts welcome. Wow, that's a long post (sorry).

    Freddie
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