Strange nose that I get on 75 meters.

Discussion in 'General Technical Questions and Answers' started by K8CPA, Apr 6, 2012.

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  1. K8CPA

    K8CPA Ham Member QRZ Page

    Strange noise that I get on 75 meters.

    It's a oddball one too. It moves, down the band. As far as I know; I only get it on 75 meters. I thought maybe it was some sort of solar stuff. But I seem to remember years ago on CB, we'd get a quick noise, which sounds like a huge carrier and it would go back really fast! This is slow and quite annoying. Since I filmed that video the noise has moved to 3.923.61

    Also in the mornings, on 3.865 and at like 7:00 a.m. or so... I start hearing this pulsing noise. It sounds like someone turning on a Hottub for like a few seconds and then shutting it off and then back on. Sort of a rushing sound --- and yes, this too drives me nuts.

    Here's the video:


    Anyone got any ideas on this one? :confused:

    Last edited: Apr 6, 2012
  2. KO6WB

    KO6WB Premium Subscriber QRZ Page

    Could be a lot of things. Drifting in frequency is a little different and that is usually caused by a device like a switching mode power supply, computers and other devices in the immediate area. The first thing to do is find out if it is coming from your home. To do this you have to power down the entire house including any battery backup temporary power devices (UPS) and anything else that has a battery in it. Now using your own radio on a battery, see if the noise went away. If it did then the problem is in your house. If it didn't go away then you would have to take the rig out for a walk around the neighborhood and see if it goes up anywhere. Once you have found the peak that will be just about the location of the noise source. This may take sometime and the noise source can be elusive.
    I have been listening on 80/75 and haven't heard this on the west coast.
    You will have to monitor what conditions are around when it occurs. Like it gets worse, or better during and after a rain. Keep tabs on the temperature and see if that has any relation. The time of day it shows up. Stuff like this will help eliminate some things and point to others.
    Hope this helps
    Last edited: Apr 6, 2012
  3. W5DXP

    W5DXP Ham Member QRZ Page

    My nose gets bent out of shape every time I listen to 75m.
  4. K8CPA

    K8CPA Ham Member QRZ Page

    It was a typo, yes, I know. :p
  5. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    I have the same sort of noise. It's local, probably some sort of power supply for/or electronics.

    Switching power supplies often drift in frequency because they are basically a free running oscillator.
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