Close Station Interference

Discussion in 'Ham Radio Discussions' started by W0CD, Jan 17, 2021.

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  1. W0CD

    W0CD Premium Subscriber QRZ Page

    Team,

    Good evening! There's a club station just down the street from me (~1.2mi) with several towers and is operated remotely operated by several hams. Tonight I jumped on 6m (FT8). Unfortunately, I couldn't do much operating based on the attached coming from that station.

    Being relatively new to FT8, is this a result of a high power, close range, or poor ALC / radio config. And is there anything I can do to reduce the impact?

    Thanks.

    [​IMG]
     
  2. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    I feel your pain but it is Time to change frequency and ir add filters and attenuators. What kind of rig are you running?
    With the right filters you should be able to work on the same band, big QRO contest stations do it all the time.
    I have antennas separated by 400 to 1,500 feet and I can monitor different frequencies are modes on the same band no problem/ with no special filters.
     
    W0CD likes this.
  3. W0CD

    W0CD Premium Subscriber QRZ Page

    Thanks for the feedback. I'm running an IC-7300 with a simple trapped dipole in the attic.

    Ref your update: I'll shop around and see what I can find. I've hand no problems on the lower frequencies with hams in the area. I've worked several within a mile or two no problem. It seems to be a 6m issue so far. Although, I don't think I've been operating when they've swung that boom around and cranked up the amp during a contest.
     
    K0UO likes this.
  4. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    Make sure your operating the 7300 as a SDR Radio correctly. SDR open as a barn door so don't use preamps and use attenuators on 40 and lower frequencies and you will find it helps tremendously.
     
    W0CD likes this.
  5. W0CD

    W0CD Premium Subscriber QRZ Page

    I'll give that a try. Thanks.
     
    K0UO likes this.
  6. KP4SX

    KP4SX Premium Subscriber QRZ Page

    How strong is that main signal at ~1200 registering?
    My first knee jerk inclination is that they are the ones throwing out the garbage.
     
    WQ4G and W0CD like this.
  7. W0CD

    W0CD Premium Subscriber QRZ Page

    The main signal was +5db around 882 (JTDX decoded ALL of those emissions.. which I have a screenshot of as well).
     
  8. KP4SX

    KP4SX Premium Subscriber QRZ Page

    Do other stations at +5 look like that?
    What happens when you apply an attenuator?
     
    WQ4G likes this.
  9. WQ4G

    WQ4G Ham Member QRZ Page

    Is that what you are seeing while on a certain frequency? Or is that what you are seeing through out the entire 6 meter band?

    If it is limited to a certain frequency then I would say it's probably due to the close proximity. If it is across the entire 6 meter band then there is a problem.

    Maybe they're using a KW for FT8 transmissions...

    WQ4G
     
    PU2OZT likes this.
  10. W0CD

    W0CD Premium Subscriber QRZ Page

    That's the entire FT8 portion of 50.313 (about 3khz).

    Using the attenuator doesn't help much.

    (I'm not sure what happened to the original image. I can't seem to link another one now either)
     
    Last edited: Jan 17, 2021

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