New noise - Many bands

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  • Updated 2 years ago
Sigh... The problem with having a great radio is you hear more.  The problem with having an SDR radio is you also see more.

I think these kinds of noise always existed in my life as a Ham but I probably never saw them much before because I had no pan to glance up on.

The other day I found that one of my USB hubs was causing lots of wabblely noise, especially on 40m.  When I unplug it, it cleans up nicely.  So I am replacing that with a better one, also that can be powered from my 12V supply.

I was hopeful I would find the big noise peaks I see on 20m so I completely killed power to my house at the mains.   Back inside I used my laptop and 6500 running from a battery and much to my dismay the noise peaks on 20, 15 and a few other bands remained.  

So I think since my house was completely dead.  IE no power from the mains (about 100 feet way) to the house I can rule out that these are caused by something I have.

So now I have to make a small directional antenna and try to find these.  It's never easy is it?



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Mark - WS7M

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Posted 2 years ago

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Walt - KZ1F

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WOW! You've had the radio for awhile now, Are all these new, as in recent additions to your pan
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Mark - WS7M

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Those peaks pointed to by the arrows are like a month old.  Perhaps even related to when it got really cold.
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George Molnar, KF2T, Elmer

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You are so right, Mark. Good luck with remediation. Hope you get "lucky" with something in your house hanging on with an internal battery or UPS. It's amazing how noise comes from all over these days. Some beam headings (even at UHF!) are several s-units worse than others, too.
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Mark - WS7M

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Hi George, I hadn't considered it was something on a UPS... I will check that next week.  Thanks!
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Richard McClelland, AA5S

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Hi Mark, I don't know if you'll find this of value but I don't see this noise at my qth (about 2.5 miles NW of you).  I have a Flex 1500 and 250' horizontal delta loop at 35'.  I believe you also have a Flex 1500, you might fire that up and see if the noise is still there on the 1500.  If not, then we can conclude that the 6500 has a far better receiver than the 1500.  Otherwise, the noise source is close to you.  Have you tried burning down your neighbor's houses?  That should take care of any errant plasma televisions nearby (but don't tell the police that I said that you should try this.)
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Mark - WS7M

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LOL... I think I could avoid those noise areas before taking those drastic measures!  LOL...

I will try the 1500 and George had a good point.  Maybe something on a UPS.

Mark
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Mark - WS7M

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Richard, Got my flex 1500 hooked up and running to a different antenna and the noise is still the same at least on 20m where I checked.

I'm gonna see if I can figure out a way to connect my laptop to PowerSDR and a small battery to carry the 1500 around with a small antenna and see if I can figure out the source.

At this point I'm pretty sure it's not in my house.  I thought about the UPS thing and realized I really only have one and that is on this primary computer at my development station.  As a test I shut it down and the issue remained.

Changing out USB hubs helped a lot.  Funny that two identical hubs give different results.  6 port hubs, one was clean, the other messy.   I got two new 8 port hubs and plugged them in yesterday with their little power adapters (plan to cable direct to my 12V supply when I get time) and they were clean.

So I have to look at those noise peaks in the pic and see if I can figure those out.
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James Whiteway

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Mark, your photo looks a lot like what I started out with. I found two(actually 3) offenders. The first was the wall wart for my Bose Companion III Series II speakers.
Disconnected that, and the regularly spaced spikes went away. Second, the power supply in my home built pc (ThermalTake) was causing a lot of problems. Switched it out for a new, 850 watt Corsair and all but a tiny bit of interference went away. I used a portable AM radio to find those two. Getting it close to the source caused it to howL.
Good luck,
James
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Ned K1NJ

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      If you can't seem to find a source in your house, sometimes a short drive
with your car AM radio on will give you a clue.  I found an arcing insulator on
a pole that way.  It only did it after raining and had dried a little.  The
electric company appreciated the information and fixed it within a few hours.
Portable AM radios, especially with loopsticks are very useful.

Ned,  K1NJ