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

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  • mattdav
    replied
    Thanks for that. I've done that and checked the status of FR24Feed and Piaware but I still get the error. Is there any way I can see what is locking the dongle?


    pi@raspberrypi:~ $ sudo systemctl stop fr24feed
    pi@raspberrypi:~ $ sudo systemctl stop piaware
    pi@raspberrypi:~ $ sudo systemctl stop dump1090-fa
    pi@raspberrypi:~ $ fr24feed-status
    [FAIL] FR24 Feeder/Decoder Process ... failed!
    pi@raspberrypi:~ $ piaware-status
    PiAware master process (piaware) is not running.
    PiAware ADS-B client (faup1090) is not running.
    PiAware ADS-B UAT client (faup978) is not running (disabled by configuration settings)
    PiAware mlat client (fa-mlat-client) is not running.
    Local ADS-B receiver (dump1090) is not running.

    no program appears to be listening for ES connections on port 30005.
    faup1090 is NOT connected to the ADS-B receiver.
    piaware is NOT connected to FlightAware.

    got 'couldn't open socket: cannot assign requested address'
    dump1090 is NOT producing data on localhost:30005.

    Your feeder ID is xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (from /var/cache/piaware/feeder_id)
    pi@raspberrypi:~ $ sudo rtl_power -f 800M:1200M:100k -i 30 -c 50% -e 30m -g 30 -F 9 >scan.csv
    Number of frequency hops: 286
    Dongle bandwidth: 2797202Hz
    Downsampling by: 1x
    Cropping by: 50.00%
    Total FFT bins: 9152
    Logged FFT bins: 4576
    FFT bin size: 87412.56Hz
    Buffer size: 16384 bytes (2.93ms)
    Reporting every 30 seconds
    Found 1 device(s):
    0: Realtek, RTL2832U, SN: 00001000

    Using device 0: Generic RTL2832U
    usb_claim_interface error -6
    Failed to open rtlsdr device #0.
    pi@raspberrypi:~ $

    Leave a comment:


  • abcd567
    replied

    usb_claim_interface error -6
    Failed to open rtlsdr device #0

    First stop dump1090-fa, then run the scan

    Code:
    sudo systemctl stop fr24feed  
    sudo systemctl stop piaware  
    sudo systemctl stop dump1090-fa

    Leave a comment:


  • mattdav
    replied
    Hi,

    I need some help. I've followed this thread with interest and followed the instructions to see if I need a filter. Initially I was running the FR24 image and have been feeding data for some time. I came across this thread, followed the instructions, and found that I have strong mobile signals between 925 mhz and 960 Mhz. So I bought a FlightAware 1090 filter - the new one with the dark blue label. Whilst waiting for that to arrive, I followed weidehopf's bundle install for dump1090fa.

    The filter is now in place and all's working well. I am now feeding FR24 and FlightAware. I want to re-run the frequency scan to compare the filtered and unfiltered images and this is where I'm stuck.

    I've followed the instructions in this thread again and get the message below. I've searched this forum and confirmed that I've stopped everything listed. I've even tried some of the blacklisting commands suggested here (and learned why that may be necessary!). So, how can I determine what's locking my dongle so that I can re-run my scan?

    Number of frequency hops: 286
    Dongle bandwidth: 2797202Hz
    Downsampling by: 1x
    Cropping by: 50.00%
    Total FFT bins: 9152
    Logged FFT bins: 4576
    FFT bin size: 87412.56Hz
    Buffer size: 16384 bytes (2.93ms)
    Reporting every 30 seconds
    Found 1 device(s):
    0: Realtek, RTL2832U, SN: 00001000

    Using device 0: Generic RTL2832U
    usb_claim_interface error -6
    Failed to open rtlsdr device #0.

    Leave a comment:


  • abcd567
    replied
    Originally posted by cathalferris View Post
    For Option 1, with the dongle attached to a Raspberry Pi and using Buster as the Raspbian OS flavour of choice, note that the package name under Buster is "python-pil" instead of "python-imaging".
    Thanks for the useful info. It will help those who use buster

    Leave a comment:


  • cathalferris
    replied
    For Option 1, with the dongle attached to a Raspberry Pi and using Buster as the Raspbian OS flavour of choice, note that the package name under Buster is "python-pil" instead of "python-imaging" - otherwise everything else appears to be correct, and generates the nice pictures the same as the other examples above.

    For my current location I've got very strong GSM signals, and have had very good results (out to the heywhatsthat limit anyway) with the RTL-SDR triple-filtered LNA, with both the RTL-SDR dongle and Airspy Mini receivers.

    Leave a comment:


  • TomNJerry
    replied
    Very useful thread, but buried deep under less important threads. Hard to find.
    My post has brought it at the top of list for now, but in due course it will get buried again.
    Last edited by TomNJerry; 2019-06-10, 18:18.

    Leave a comment:


  • abcd567
    replied
    Ceramic being too expensive, SAW is a reasonable choice. It should be able to remove cell/mobile signals you have.

    https://discussions.flightaware.com/...ation/40388/32
    Last edited by abcd567; 2018-09-16, 16:51.

    Leave a comment:


  • 9944990
    replied
    Thank you @abcd567, Your the best
    I am thinking of buying Uputronics 1090MHz ADS-B Filtered Preamp. The Ceramic one is way more expensive then the SAW one.
    Is it worth it? How better reception do you think can I get with Ceramic filter compared to SAW?

    Leave a comment:


  • abcd567
    replied
    The strong cell/mobile frequencies overload the dongle, and performance drops. Removing/reducing these cell/mobile signals improves reception of weak signals from far away planes.

    Since 960 Mhz is very close to 1090Mhz, you will need a good filter to remove it.

    EDIT:
    The flightaware filter is good in removing cell/mobile signals in 850 mhz band, but is not effective in removing cell/mibile signals in 960 mhz band. You may need a SAW filter, or Ceramic filter, or Cavity filter to remove 960 mhz band.
    Last edited by abcd567; 2018-09-16, 13:35.

    Leave a comment:


  • 9944990
    replied
    Can a filter improve my 1090 Mhz signals? Does this effect my 1090 Mhz reception? Sorry if it is a stupid question .
    I thought if there is no interference around 1090 Mhz then nothing to worry?

    Leave a comment:


  • abcd567
    replied
    The scan shows that you have strong cell/mobilesignals between 925 mhz and 960 Mhz. This is the interfering signal.

    Leave a comment:


  • 9944990
    replied
    Followed Option 1 here and here is the results:

    Full scan:
    scan.jpg

    Part 1
    1.jpg

    Part 2
    2.jpg

    Part 3
    3.jpg


    As I see nothing is interfering 1090 MHz signals?

    Leave a comment:


  • Coxy
    replied
    I have a Pro + and still had huge noise at the 820 to 860 and 940 to 960 range. I added the FA filter and it does knock out the cell signals in the 800 range, but not a lot from the 900. This still allowed me to see aircraft further out with higher accuracy (less sporadic drop outs). I am receiving over 200Nm in some area's.

    I will add in my SAW filter soon (once i can find the sma connectors) and hopefully see the 900 signals reduce as well.

    abcd567 is correct with saying that you will more than likely need to drop your gain to reduce the overload, i have dropped mine from 49 to around 30 atm and haven't lost any range , probably gained a little more hits tbh.

    Leave a comment:


  • abcd567
    replied
    Originally posted by mibock View Post
    So the above images show that the internal filter of Pro Stick Plus is not so good as Pro Stick Plus AND an additional external filter?
    Not in all situations/locations. It depends on what Cell/Mobile signals that particular location has. In large number of locations, the internal filter of ProStick Plus is sufficient. In equally large number of locations, the internal filter is not sufficient and external filter improves reception. Only after adding an external filter one can say for sure if it helped or not.


    If yes: do I understand it correctly that the additional external filter does not put down the signal strength?
    Adding a filter does put down signal, but not much. Also since there is a built-in amplifier in ProStick, it easily overcomes this small loss.


    The external filter is the one in image 1 which can be normaly baught for the orange stick?
    YES, the blue cylindrical thing connected to orange prostick in img-1 is the external filter.
    You can buy the external filter with ProStick, or separately.
    You can also buy other makes of filters available on line on their sites, or on eBay and Amazon.

    Leave a comment:


  • mibock
    replied
    So the above images show that the internal filter of Pro Stick Plus is not so good as Pro Stick Plus AND an additional external filter?

    If yes: do I understand it correctly that the additional external filter does not put down the signal strength?

    The external filter is the one in image 1 which can be normaly baught for the orange stick?

    Leave a comment:

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