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Discussion in 'General Technical Questions and Answers' started by KO7PAS, Jun 30, 2021.

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  1. KO7PAS

    KO7PAS Ham Member QRZ Page

    I have grounded everything imaginable to a ground stake outside the house, and knocked it into the ground about 3.5' (4' ground stake). I have moved laptop, LED lamp, power supplies, put in a power block, put a noise filter on the power lines to my radios. I have even grounded the metal shelving that I use to mount my radios on. I still am getting noise. Also at 148.350MHz, I have a s3 to s7-s9 solid noise signal. 300' away is a transformer on a telephone pole, with a power line to a barnyard light, then to a another power pole that splits to 3 different units. That power split is less than 50' away from my antennas. I could move my antennas, but they would be in someone else's yard, and if I move them the other way, my antennas would be in the trees of the other neighbor.

    I'm out of ideas here... I'm sure that the power lines are putting off RFI especially at the split, the transformer, the neighbors security cameras and who knows what else...

    I'm out of ideas here... My noise floor is way too high.
     
    KO4ESA likes this.
  2. KO4ESA

    KO4ESA Ham Member QRZ Page

    The baofeng I use to monitor local frequencies splutters when I have the IPhone charger plugged up.
    We have a transformer on one side of our house and power lines zigzagging all over the property.
    The kenwood thd74 I can transmit on if I stand at the edge of the embankment and hold the radio in one spot.
    It feels like a science experiment just to check in to the local net.
    Hopefully you will find what is causing the noise.
    KO4ESA
    WRJR757
     
    KO7PAS likes this.
  3. KO7PAS

    KO7PAS Ham Member QRZ Page

    Thank you! :)
     
    KO4ESA likes this.
  4. K6BRN

    K6BRN XML Subscriber QRZ Page

    Hi Patti:

    What bands and modes are you seeing the RFI on? From your post, it appears that it's a 2M band problem, possibly with SSB and is due to some source outside your home. Because FM is pretty resistant to single-tone interference and is usually not a weak signal mode.

    In this case, grounding will not help much nor will moving your antenna. Power line noise interference on HF is frequent but on 2M it's rare. Grounding the coax shield or adding a common mode choke on HF bands CAN help lower locally generated noise conduction into your receiver, but not so much on VHF/UHF (2M).

    Your best bet is to contact a local ham who like to "Fox Hunt" or track down local RFI and ask them to help.

    And... a 4 foot ground rod is very inadequate for grounding. Generally an 8 to 10 foot rod is used and tied in to the house power/entrance panel ground in a very specific way. Grounding and bonding is a complex subject, made simpler and well explained by the following ARRL book, which I recommend:

    https://www.arrl.org/shop/Grounding-and-Bonding-for-the-Radio-Amateur

    Best Regards,

    Brian - K6BRN
     
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  5. KO7PAS

    KO7PAS Ham Member QRZ Page


    Good stuff for sure! Unfortunately, the ground around my home is rock and it took a lot of work just to get 3.5' into the ground, but better than nothing. I will consider a grounding rod that's bigger.
     
    KO4ESA likes this.
  6. W3TKB

    W3TKB XML Subscriber QRZ Page

    Simple solution for rocky soil: go to a tool rental company and rent a roto-hammer or demolition hammer. They are big, heavy, and noisy, but will drive an 8 foot ground rod into most any soil quicker than snot.

    There are a couple YouTube videos that demonstrate the procedure using one of these tools. I don't remember the exact titles now but if you can't find them, let me know and I can back check my YouTube history.

    My soil is mostly rock and shale. It would have taken who knows how long to drive a ground rod with a sledgehammer; way longer than I would care to. I went to a rental place and got a demolition hammer and the neccessary bit; it was about $50 for a 6 hour rental. Your prices may vary. I guarantee it is well worth it.

    It took longer to get set up and negotiate everything into place than it did to actually drive the rod into the ground. I did the whole thing myself, but I would recommend having at least one person to help, maybe two. You have to get a short ladder to be able to position yourself above the 8 foot ground rod...that is the tricky part where help would be needed. The hammer is VERY heavy! But once I got into position and started, the demo hammer drove that 8 foot rod all the way into the ground in about 10 minutes! And that includes the time I had to climb back down off the ladder and reposition myself.

    If you know someone who has a demolition hammer, so much the better. Electricians that have to install a lot of ground rods usually have one in their arsenal of tools. Trust me, save your arms...rent the hammer.

    Brando
     
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  7. WA4SIX

    WA4SIX Ham Member QRZ Page

    The 1st step is to turn off all breakers in your home. See if the noise comes from there. Once that is eliminated, you can go further. Many times, it's a cell phone charger or other switch mode power supply.

    Ed
     
    KA9UCN, W6KCS, KO4ESA and 5 others like this.
  8. KP4SX

    KP4SX Premium Subscriber QRZ Page

    Ditto that. Grounding and choking rarely do anything to help if the noise is being picked up by your antenna.
     
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  9. K6BRN

    K6BRN XML Subscriber QRZ Page

    On what bands and modes are you seeing this problem? Just 2M? And FM, SSB or ... ?

    Brian - K6BRN
     
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  10. KA3VSP

    KA3VSP XML Subscriber QRZ Page

    First thing I look for is a switching power supply. AC wall warts, or other power supplies that aren't built into electronic devices, such as those powering network switches, IP cameras, POE devices, speakers, monitors, TV's, etc. But, yes, trip your AC power breakers to test to see if the issue goes away. If so, start unplugging devices. You have to unplugged the devices, just don't turn them off because usually they're not really turned off. Also, keep in mind that the noise source could be in a neighbor's house.
     
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