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Diagnostic software for flex

IZ2ODM
IZ2ODM Member
Hello guys,
it's been a few weeks now that I have a lot of QRM and looking the panadapter is not clear if it is due to the high level of QRM ( domestic , led or something like that) or some problem of Flex. 
Panadapter show a sort of "wall" from 14.050 to 18.100 Mhz ...also close to 7 Mhz . IS there some diagnostic software in order to check Flex for RX section ? Maybe some filters are damaged...Thanks and

73 de IZ2ODM

Answers

  • Mack
    Mack Member ✭✭✭
    edited March 2019
    Please run this test. Disconnect all antennas from the Flex and connect a dummy load or short the ANT 1 connector. Does the interference remain? If so, try unplugging wall warts or trying a different power supply. It's VERY unlikely this is a Flex hardware issue.

    Mack
    W4AX
    Alpha Team
  • WA2SQQ
    WA2SQQ Member ✭✭
    edited December 2017
    Post a photo of what you are seeing.
  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    Thanks Mack I'll try and let you know...
    73
    Roby
  • IZ2ODM
    IZ2ODM Member
    edited September 2019
    ok. Test executed with dummy load . Noise disappear , also without any load (dummy) or antenna or ground connected. This sound good.

    For WA2SQQ see photos.
    imageimage
    image

  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    image
  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    This last photo show with dummy load-->no noise

  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2017
    Yes, very good.  The noise is external of the radio.  Now comes the challenge of finding it and seeing if you can mitigate it.
  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    noooo..... Good for radio but it will be hard to find.In your opinion is right a "specific noise" or a general high QRM ?

  • Mack
    Mack Member ✭✭✭
    edited March 2019
    It will likely be a bit difficult to find but based on the signal strength it's probably within your home. Here's the way I would approach the problem:
    1) Identify which circuit breaker the Flex and computer are connected to. Leave this breaker on.
    2) Turn off each other breaker ONE AT A TIME to see if the noise disappears. If and when you identify the circuit then go unplug any transformer or appliance until you locate the source. 
    3) If you cannot find the offending circuit then the only breaker left to test is the one with the Flex Radio and computer. Find a 12 volt batter to power the Flex and use a laptop or iOS device to connect to the radio which is running on battery power. Finally turn off the break on your radio/computer and see if the noise goes away. 
    4) If you don't find the issue after following ALL of these steps then check back here and I'll discuss how to find noise issues outside your house.

    Mack
    W4AX
    Alpha Team 
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2017
    Could be a motor noise.  I do not recall ever seeing anything like this before.
  • Jim K4JAF
    Jim K4JAF Member ✭✭
    edited December 2017
    Is the noise your seeing constant all the time or does it come and go during the day?
    Also do the noise spikes within the wide band noise vary in amplitude and frequency?

  • G8ZPX
    G8ZPX Member
    edited July 2018
    That noise is almost certainly either VDSL broadband or PLT / PLA adaptor noise. The signature is very familiar to me and obviously quadrature digital signalling. The very deep notched at 17.6 and 14 MHz are pre-coded notches where the box of trick is being prohibited from TX'ing.
  • G8ZPX
    G8ZPX Member
    edited July 2018
    That noise is almost certainly either VDSL broadband or PLT / PLA adaptor noise. The signature is very familiar to me and obviously quadrature digital signalling. The very deep notched at 17.6 and 14 MHz are pre-coded notches where the box of trick is being prohibited from TX'ing.
  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    It will be hard to find...Thanks G7BCX



  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    Just a couple of questions , in case of VDSL broadband noise how far from my ant/radio can be in order to capture noise ? I have a cabinet  of  Thelephone company 40mt from my ant but frankly speaking it is there by many years . Same question for PLT adapter , how fare can be from my shack? Thanks for any reply .

    Roby IZ2ODM
  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    Always the same Jim during the day/night 24h or almost when i'm on the shack/radio
  • John - K3MA
    John - K3MA Member ✭✭
    edited April 2018
    You might want to look at this document.  The spectrum looks very similar to yours.  You can also search for RSGB VDSL Interference.

    John K3MA

    http://rsgb.org/main/files/2017/08/2017-RFI-Update-RSGB-Convention.pdf
  • Steve G1XOW
    Steve G1XOW Member ✭✭
    edited May 2020
    http://g1xow.uk/   scroll down a page or two for lots of images of VDSL QRM to see how devastating it is.
  • Stan VA7NF
    Stan VA7NF Member ✭✭✭
    edited December 2017
    Thanks John for this RSGB reference. 
    The frequency range directly matches Roby's spectrum display, with the U2/D3 indicating VDSL service > 50Mbps. 
    In NA we used to have problems with the cable TV and internet which were helped by better RG-6 and good unbalanced transformers.  Home telephone wiring can make excellent antenna systems.
    The RSGB document looks good for a club presentation, with permission.
  • Manfred HB9FLU
    Manfred HB9FLU Member ✭✭
    edited December 2017
    VDSL or PLC

    73 de Manfred
  • IZ2ODM
    IZ2ODM Member
    edited December 2017
    Thanks John and Stan . Read immediately and , frankly speaking, what it is showed seems totally similar at mine. Sorry for following and **** question ; It is not a matter of good filter? I mean...if I 'd use something like 4O3A bandpass filter may I solve something ?

    Iz2ODM Roby
  • Stan VA7NF
    Stan VA7NF Member ✭✭✭
    edited December 2017
    Roby, unfortunately no filters on your receive will work; the interference signal is on your receive frequency.
     In the RSGB presentation they talk about line balance and underground.  The RF signal is part of the DSL architecture so it will exist.  Our problem is keeping that signal away from radiating to our antenna. 
    That is by perfecting the line balance (makes it a non radiating feed line), covering it with a shield such as shielded telephone cable or grounded metal conduit, or suppressing the radiated signal (underground).  Any user that adds a telephone extension with a loose wire has just made a whole house transmitting antenna.
  • Stan VA7NF
    Stan VA7NF Member ✭✭✭
    edited December 2017
    Second thought.
    if the upload frequencies are stronger than the download then the interference source is near the user side (your own VDSL modem), if the other way (D1/D2/D3 stronger than U1/U2 - see presentation for exact frequencies) then it is communications company near their hub.
    Your spectrum display is just abound the 20M band, and looks like your antenna (resonant I assume around 20M) is more sensitive in that range.
    Try a different antenna (or loosen the connector so only the centre makes contact) and take a 0-14Mhz spectrum view.  That should show the different frequencies and their strengths.

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