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Author Topic: Question for Elmer - Audio blip when turning off any power source in my house  (Read 6754 times)
K4RVN
Member

Posts: 812




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« Reply #15 on: April 22, 2013, 06:31:39 AM »

Mike,
If after trying all the other advice you get and the problem is still there, buy you a MFJ-915 RF Isolator from someone like Giga parts, DX engineering, HRO, or others.  Connect the isolator to your transceiver via a short coax and the other end to your antenna.  The mounting instructions come with the 915. Good luck, keep us posted on the solution.

Frank
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W6EM
Member

Posts: 900




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« Reply #16 on: April 22, 2013, 06:27:24 PM »

Mike:

I recently retired from doing forensic investigations.  Most were examination of fire scenes of suspicious cause and origin.  Those where an electrical source was suspected.  What you describe is most likely the RF spectrum of an electrical arc that is creating broad bandwidth noise.  Enough energy that your antennas and receivers pick it up.

You at first said or strongly implied that any switching of AC loads in your home caused the burst.  But, your last post indicated that when you turn your PC on, no arc burst was created.  Assuming that is a normal desktop PC with a switching power supply built in, that says something.  Since there are apparently sections of your home wiring branch circuits that don't produce the arc/zap, then the problem is most probably on one of your branch circuits from your electrical panel.  It could be a wire nut splice or possibly a screw terminal on a switch or outlet.  It could be either along the white or neutral wire or the black wire.

I'd recommend that you call in an electrician to assist you in locating and repairing the problem.  But, you could assist him and determine which circuit breaker supplies the circuit with the problem.  Once you find switches or appliances that generate the arc, trip the circuit breakers until you find the one that supplies power to the circuit with the problem.  The electrician can then begin inspecting the junction boxes to find the problem before it could cause a fire.

Several fires I investigated were caused by wire nut splices that either weren't tightened properly or the wires were not inserted far enough in them to make good electrical contact.  What happens in that case is a progressively higher resistance connection and elevated temperature while under load.  Serious stuff.   
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KD2CJJ
Member

Posts: 369




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« Reply #17 on: April 22, 2013, 07:12:15 PM »

My station ground is not the best being in the second floor of my house.  Everything is grounded to my water pipe.  So it could be a contributor... I will try putting a balun at the rig as I have an extra balun (guanella balun).   I just upgraded my rig and noticed its not as frequent but still there.

My neutral and ground are separate and distinct.  There is no stray voltage on the ground or neutral either.

I will report back on the balun.

Mike,
If after trying all the other advice you get and the problem is still there, buy you a MFJ-915 RF Isolator from someone like Giga parts, DX engineering, HRO, or others.  Connect the isolator to your transceiver via a short coax and the other end to your antenna.  The mounting instructions come with the 915. Good luck, keep us posted on the solution.

Frank
Logged

73

Mike
KD2CJJ
KD2CJJ
Member

Posts: 369




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« Reply #18 on: April 22, 2013, 07:20:58 PM »


The pc and light switch on in the same circuit that I am complaining about.  What's weird is when I went to test it tonight of course I could not reproduce the issue! Even with my rotor controller!!

I'm wondering if there is a device that is plugged in that is amplifying the signal on the circuit or whole house which is now NOT plugged in and why it's not surfacing.

I'm still searching.


Mike:

I recently retired from doing forensic investigations.  Most were examination of fire scenes of suspicious cause and origin.  Those where an electrical source was suspected.  What you describe is most likely the RF spectrum of an electrical arc that is creating broad bandwidth noise.  Enough energy that your antennas and receivers pick it up.

You at first said or strongly implied that any switching of AC loads in your home caused the burst.  But, your last post indicated that when you turn your PC on, no arc burst was created.  Assuming that is a normal desktop PC with a switching power supply built in, that says something.  Since there are apparently sections of your home wiring branch circuits that don't produce the arc/zap, then the problem is most probably on one of your branch circuits from your electrical panel.  It could be a wire nut splice or possibly a screw terminal on a switch or outlet.  It could be either along the white or neutral wire or the black wire.

I'd recommend that you call in an electrician to assist you in locating and repairing the problem.  But, you could assist him and determine which circuit breaker supplies the circuit with the problem.  Once you find switches or appliances that generate the arc, trip the circuit breakers until you find the one that supplies power to the circuit with the problem.  The electrician can then begin inspecting the junction boxes to find the problem before it could cause a fire.

Several fires I investigated were caused by wire nut splices that either weren't tightened properly or the wires were not inserted far enough in them to make good electrical contact.  What happens in that case is a progressively higher resistance connection and elevated temperature while under load.  Serious stuff.   
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73

Mike
KD2CJJ
K1CJS
Member

Posts: 6061




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« Reply #19 on: April 23, 2013, 03:56:11 AM »

...My neutral and ground are separate and distinct.  There is no stray voltage on the ground or neutral either....

They had better not be.  They have to be connected together in the breaker panel.  If they aren't, then that is most likely your problem--and if that is the case, I'd suggest getting an electrician to fix it, because your home electrical system isn't up to code.
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W6EM
Member

Posts: 900




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« Reply #20 on: April 23, 2013, 04:55:04 AM »


The pc and light switch on in the same circuit that I am complaining about.  What's weird is when I went to test it tonight of course I could not reproduce the issue! Even with my rotor controller!!

I'm wondering if there is a device that is plugged in that is amplifying the signal on the circuit or whole house which is now NOT plugged in and why it's not surfacing.

I'm still searching.

Problems like you describe are often intermittent.  You didn't respond to my questions about other loads/appliances in other parts of your home.  Especially, 240 volt loads such as an air conditioner compressor, oven range, or electric range oven element.  If the arcing is only on the circuit that supplies your rotor and PC, then it's most likely what I suspected as to it being a screw terminal or wire nut somewhere between the outlet that supplies your PC and your main panel.


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W6EM
Member

Posts: 900




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« Reply #21 on: April 23, 2013, 05:06:59 AM »

...My neutral and ground are separate and distinct.  There is no stray voltage on the ground or neutral either....

They had better not be.  They have to be connected together in the breaker panel.  If they aren't, then that is most likely your problem--and if that is the case, I'd suggest getting an electrician to fix it, because your home electrical system isn't up to code.

Separate and distinct probably was his definition of them being two separate conductors from the main panel to the outlet(s) in question.  "No stray voltage" would be normal if nothing was turned on.  But, one should expect a small voltage rise on the neutral at a significant distance from the main panel under load due to the neutral conductor resistance.  He would have a code issue if the grounding conductor and neutral were interconnected anywhere else besides the main panel.
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KD2CJJ
Member

Posts: 369




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« Reply #22 on: April 23, 2013, 06:19:13 AM »

Yes... thank you for clarifying my statement.

I dont believe its a fundamental issue with my electrical system as the issue does not resonate on any other electrical device (including a house hold AM radio) - I do believe though my poor RF ground (water pipe), location of my rig (second floor),  location of my antenna (over the side of my house on a mast which is literally 33 feet above the electrical panel) are major contributors.  This weekend I will try a few things to isolate the problem.  I am also planning on putting a better ground outside my antenna - that will come soon...

Thanks for all the feedback and what to look for.. I will report back on my progress.

...My neutral and ground are separate and distinct.  There is no stray voltage on the ground or neutral either....

They had better not be.  They have to be connected together in the breaker panel.  If they aren't, then that is most likely your problem--and if that is the case, I'd suggest getting an electrician to fix it, because your home electrical system isn't up to code.

Separate and distinct probably was his definition of them being two separate conductors from the main panel to the outlet(s) in question.  "No stray voltage" would be normal if nothing was turned on.  But, one should expect a small voltage rise on the neutral at a significant distance from the main panel under load due to the neutral conductor resistance.  He would have a code issue if the grounding conductor and neutral were interconnected anywhere else besides the main panel.
Logged

73

Mike
KD2CJJ
N8YQX
Member

Posts: 83




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« Reply #23 on: April 23, 2013, 04:43:58 PM »

Is your AGC adjustable?  Fast AGC should minimize the problem.

I have similar problem with the whole house humidifier.  The water is regulated with a solenoid, and when it kicks in, it causes a broadband noise (impulse noise).  If the AGC is set to slow response, the release time is long, and it can be quite annoying.  With fast AGC, my release time is quite fast, and I only miss one syllable at most.

I know this is not the ideal solution, but if your radio has an adjustable AGC, it's a quick fix until you get the problem resolved properly.
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73,
N8YQX
KB3HG
Member

Posts: 404




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« Reply #24 on: April 24, 2013, 10:57:03 AM »

FWIW,
Get a CHEAP transistor AM radio. the cheesier the better turn it on, have someone flip switches, the AM radio will go nuts from the noise the closer you are to the problem. Is a  simple way to locate the source.

Blind guess a loose connection. At the panel or common point ground. 

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KD2CJJ
Member

Posts: 369




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« Reply #25 on: April 26, 2013, 06:35:18 AM »

I did some tests... the issue is MOSTLY localized to the circuit that the shack is on.  Other circuits dont produce the issue except for my boiler when the blower turns on... but its a very small blip.  I was wrong in this fact. Keep in mind though my shack is on the second floor story of my house, the feed-line goes up into the attic across then up again out then up to my mini beam hanging off the side of the house.  Its about 40 feet of feedline.. the antenna is about 15 feet above my shack to the side about 20 feet.

I played around with some settings the AGC does help but then it affects the listenability when I have my RF gain up.  The Noise Blanketer completely eliminates it if I set it to 30%....  Im fine leaving the NB on at 30% as it doesnt affect my listenability....  In the long term I will hunt down why with an AM radio (funny I dont have one).

Lastly I did notice that the issue is a "typical" issue based on my internet search.  Any device that has a high current draw will create a small spark when plugged in (you can test it for your self. With that said, the light switches in my house seem to make a small spark when I turn them on/off... From my research this is somewhat normal for "cheap" light switches.   Every light switch that creates this "small spark" creates this annoying spike.  In parallel I will replace all these cheap light switches - of course this will NOT fix my issue with the switches on my rotor.

I will report back..

PS do a google on "why is there a spark form the light switch when I turn on or off the lights" to read on what I found..

FWIW,
Get a CHEAP transistor AM radio. the cheesier the better turn it on, have someone flip switches, the AM radio will go nuts from the noise the closer you are to the problem. Is a  simple way to locate the source.

Blind guess a loose connection. At the panel or common point ground. 


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73

Mike
KD2CJJ
KB9YNB
Member

Posts: 115


WWW

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« Reply #26 on: April 30, 2013, 12:46:27 AM »

...My neutral and ground are separate and distinct.  There is no stray voltage on the ground or neutral either....

They had better not be.  They have to be connected together in the breaker panel.  If they aren't, then that is most likely your problem--and if that is the case, I'd suggest getting an electrician to fix it, because your home electrical system isn't up to code.

Slight correction:  The ground an neutral should be connected at the first disconnect after the meter.  If your breaker box is located far away from your meter, then you probably have a disconnect at/near the meter, which is where your ground and neutral will be bonded.
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K1CJS
Member

Posts: 6061




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« Reply #27 on: April 30, 2013, 04:16:26 AM »

Slight correction:  The ground an neutral should be connected at the first disconnect after the meter.  If your breaker box is located far away from your meter, then you probably have a disconnect at/near the meter, which is where your ground and neutral will be bonded.

Not quite.  The neutral and the ground should be bonded together at the breaker box, and usually are by the simple method of directly mounting both the neutral busbar and the ground busbar directly to the metal breaker enclosure.  The meter socket does not have a 'ground' connection point, it has a 'neutral' connection point since the neutral is one three cables connecting the breaker box to the meter in a typical three wire 240 volt household system with the other two cables being the two opposite 'hot' phases of the system.  That neutral connection is the connection that is 'grounded', for all intents and purposes.
« Last Edit: April 30, 2013, 04:18:43 AM by K1CJS » Logged
KD0REQ
Member

Posts: 1047




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« Reply #28 on: April 30, 2013, 08:52:52 AM »

what happens if you string an extention cord and put the radio on a different circuit for temporary testing purposes?  yes, if you have a silly ground situation, this may make metal surfaces "hot" with RF in the shack, it may not.

W6EM knows what he's talking about, and now that it's apparently isolated to the shack circuit, time to nail that one down for sure.  it could be a backstab connection downstream, or even a breaker that has "chattered" contacts, but it's sounding like a crummy contact someplace in that circuit.  if true, first step for me would be to replace every outlet and switch on that circuit with screw-down back-wired devices, and check the wire nuts to make sure the wires were twisted before being inserted into the wire nuts.  those two steps could get the high resistance piece out of your way forever.

and indicate a continuing improvement project in the house.
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N1UK
Member

Posts: 1588




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« Reply #29 on: April 30, 2013, 09:57:03 AM »

I had a similar loose connection issue to what W6EM talks about. One day I switched on the Astron 35 amp PSU in my shack and everything went off. I checked the breaker and it was fine. Then I noticed that the first socket in the shack 115V string was working. I turned off the power at the breaker box and removed the working receptacle from the wall. I could see that the neutral white wire was not making a good contact. The screw was loose and the white insulation had darkened over time with the resistive heating. This is the sort of thing that W6EM states causes house fires. I removed the connection, cleaned up the copper until it was bright and clean and then remade the neutral screw connection to the receptacle tightly this time. I was lucky to find this problem.

If it was me..I would check all the connections in the shack circuit for loose connections, including the breaker connections. It might help to replace the breaker on this circuit. They are cheap. I replaced all the 40 year old breakers in my house a few years ago and I swear that the lights in the house seemed brighter at night.


73 Mark N1UK
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