Help with hum please: Ground Loop Isolator stop hum

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yoopernewsman

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I have tried sending feed thru several computers and am using a Ground Loop Isolator from Radio Shack.
Plus I moved scanner to different rooms
Still have bad hum in feed.

Any suggestions?

Help please.

I figured if I can't resolve hum its not worth sending a feed.
 

bline

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I had issues with the sound quality of my feed until I put a stereo to mono adapter on the scanner.
 

mtindor

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I encountered similar problems that were fixed by doing what Bline suggested.

I ended up buying three mono cables from radio shack (which had 1/8" jacks on one end that would plug directly into the scanner and had RCA jacks (male I believe) on the other end. Then I bought three RCA(female)-to-1/8" mono adapters so that I could plug them into the PC.

Mike
 
N

N_Jay

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The trick is to figure out EXACTLY where the hum is coming from.

Ground loop isolators ONLY help if the cause is a ground loop on the audio line.
 

E-Man

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Just to be clear, we are not talking about the GRE Digital hum right?
 
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This might not help at all, but I know from using laptops to DJ weddings and clubs that I used to get a hum off of the laptop. I solved that by using a 3 to 2 prong adapter when plugging it into my power strip. That killed the hum.
 

yoopernewsman

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Just to be clear, we are not talking about the GRE Digital hum right?
First - thank you everyone - I think this idea of online scanner feeds is long overdue and I really want to do my part

I'm a news reporter who has been listening to a scanner 24/7 for 35 years - but NOT a techie at all.

I am not sure what you mean by a GRE digital hum.

Bearcat BC350A Scanner sounds fine until hook up wire to computer.

Listening to it on the feed thru radioreference website the hum is not real bad - but its there - listen to feed in extreme northern Michigan Upper peninsula) Marquette County.

However - now I have to listen to scanner off my computer speakers - and the hum is awful.

I have tried living with it - but it's crazy awful and I have to listen to scanner for my job.

Again - hum happens no matter what computer/speakers I use (have tried on three computers in two different rooms.

I have also moved scanner into several rooms without other electronics like kitchen.

Ground loop isolator did virtually nothing to stop hum.

I will try the 3 to 2 prong adapters - will likely need about 8 of them as I have two strips with about six things plugged in - printer, two computers, modems for internet/TV/phone from same cable company.
Plus router (all 3 computers off same router).

One suggestion was running second wire from ground on my computer to ground in scanner.
But I am not sure where the ground is in my scanner and am afraid to do something I do not understand for fear of screwing up scanner and/or electrical shock.

My ground loop isolator has RCA and 1/8 inch adapters.
Unplugging channel one (red plug) RCA doesn't eliminate hum.
Unplugging channel two (white plug) RCA stops feed.

Because of that - the guy at Radio Shack - said the mono cable adapter wouldn't help.
(I don't know cause I am not techie - I just took his advice)

Ref. suggestions - thank you everyone - I will try all that are possible.

One other problem - I have spend about $30 on this so far - and while I think this scanner feed from across U.S. is a very needed and cool idea - I am a local news reporter who doesn't make a lot of money and budget is already tight.

Anyone who has spare parts they may think work I'd be happy to provide my address.

I stay up late and get up early - phone is
906-401-0109

I live in extreme northern Michigan.

Later this week I will be out of town (Arizona) for about a week.
 

yoopernewsman

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This might not help at all, but I know from using laptops to DJ weddings and clubs that I used to get a hum off of the laptop. I solved that by using a 3 to 2 prong adapter when plugging it into my power strip. That killed the hum.
Thank you - Did you mean I should take all plugs on two strips (approx 12 plugs) and put adapters on all those that are three prong to make them two prong?
Most likely need about 8 of them as I have two strips with about six things plugged in - printer, two computers, modems for internet/TV/phone from same cable company.
Plus router (all 3 computers off same router).
I have spend about $30 on this so far - and don't make much money be local reporter - budget is already tight.
That's why I want to make sure I understand you - change everything in room to two prong.
 
N

N_Jay

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The trick to finding ground loos is to temporarily break and add grounds looking for changes.
The areas to be concern are any cable where the ground is connected at both ends, such as audio cables, antenna cables, and data cables, and cables connected between devices that have their own ground points, such as power supplies.

Additionally, sometimes the hum is not a ground loop, and is just power supply hum or digital noise from one of the components.
__________________
 

yoopernewsman

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Negaunee, Michigan
The trick is to figure out EXACTLY where the hum is coming from.

Ground loop isolators ONLY help if the cause is a ground loop on the audio line.
I understand but face one obstacle.

Most of the plugs are related to computer - so I would cut off feed.
ie - modum from cable company that provides internet - the computer itself - and the router that feeds 3 computers.
Others are printer, cable company's telephone and cable TV modums

Do you have a guess as to which may be culprit ?
 

yoopernewsman

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Negaunee, Michigan
I encountered similar problems that were fixed by doing what Bline suggested.

I ended up buying three mono cables from radio shack (which had 1/8" jacks on one end that would plug directly into the scanner and had RCA jacks (male I believe) on the other end. Then I bought three RCA(female)-to-1/8" mono adapters so that I could plug them into the PC.

Mike
My ground loop isolator has RCA and 1/8 inch adapters.
basically is goes from scanner into 1/8 inch jack then immediately into group loop isolator and thru RCA cables/jacks back into female 1/8 inch long cable and then male ends plugs into microphone on my computer.
Unplugging channel one (red plug) RCA doesn't eliminate hum.
Unplugging channel two (white plug) RCA stops feed.

Because of that - the guy at Radio Shack - said the mono cable adapter wouldn't help.
(I don't know cause I am not techie - I just took his advice)

Do you agree????

If channel with no feed audio is unplugged and it doesn't stop hum - then mono issue is not problem??
 
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N

N_Jay

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Thank you - Did you mean I should take all plugs on two strips (approx 12 plugs) and put adapters on all those that are three prong to make them two prong?
Most likely need about 8 of them as I have two strips with about six things plugged in - printer, two computers, modems for internet/TV/phone from same cable company.
Plus router (all 3 computers off same router).
I have spend about $30 on this so far - and don't make much money be local reporter - budget is already tight.
That's why I want to make sure I understand you - change everything in room to two prong.
Ungrounding equipment that is supposed to be grounded may HIDE a ground loop, but in general is NOT a good idea, and can easily create an unsafe condition.
 
N

N_Jay

Guest
The trick to finding ground loos is to temporarily break and add grounds looking for changes.
The areas to be concern are any cable where the ground is connected at both ends, such as audio cables, antenna cables, and data cables, and cables connected between devices that have their own ground points, such as power supplies.

Additionally, sometimes the hum is not a ground loop, and is just power supply hum or digital noise from one of the components.
 

yoopernewsman

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Messages
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Location
Negaunee, Michigan
I had issues with the sound quality of my feed until I put a stereo to mono adapter on the scanner.
Bline,
see my answer to Mike Tindor
Do you agree with radio shack guy (see my answer)
Again I am truly thankful for all the help - but can't afford to keep buying stuff unless there is a chance it will work.
 

yoopernewsman

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Messages
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Location
Negaunee, Michigan
The trick to finding ground loos is to temporarily break and add grounds looking for changes.
The areas to be concern are any cable where the ground is connected at both ends, such as audio cables, antenna cables, and data cables, and cables connected between devices that have their own ground points, such as power supplies.

Additionally, sometimes the hum is not a ground loop, and is just power supply hum or digital noise from one of the components.
Some of your answer went over my head - while I have listened to scanner for 35 years or more - I am not techie.
Doyou think it could just be the overall power supply in my house?
Let me explain.
I live in very old house turned into four apartments - (80 to 100 years or so old - cheap landlords) because the hum problem was same even tho put scanner in different rooms - and still a hum on two computers in different rooms - that maybe it's the old electrical system in this house??

That's what I was wondering.

fyi tho - I do not have problems with anything else in house getting a hum.
Scanner was fine (no hum) without feed cable.
 

yoopernewsman

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Messages
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Location
Negaunee, Michigan
Some of your answer went over my head - while I have listened to scanner for 35 years or more - I am not techie.
Doyou think it could just be the overall power supply in my house?
Let me explain.
I live in very old house turned into four apartments - (80 to 100 years or so old - cheap landlords) because the hum problem was same even tho put scanner in different rooms - and still a hum on two computers in different rooms - that maybe it's the old electrical system in this house??

That's what I was wondering.

fyi tho - I do not have problems with anything else in house getting a hum.
Scanner was fine (no hum) without feed cable.
What do you mean by break and add grounds?
 

yoopernewsman

Member
Joined
Jul 2, 2009
Messages
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Location
Negaunee, Michigan
Some of your answer went over my head - while I have listened to scanner for 35 years or more - I am not techie.
Doyou think it could just be the overall power supply in my house?
Let me explain.
I live in very old house turned into four apartments - (80 to 100 years or so old - cheap landlords) because the hum problem was same even tho put scanner in different rooms - and still a hum on two computers in different rooms - that maybe it's the old electrical system in this house??

That's what I was wondering.

fyi tho - I do not have problems with anything else in house getting a hum.
Scanner was fine (no hum) without feed cable.
One more thing - sorry if this is dumb question r info - .

When I turn up the volume on my scanner - the sound of the hum remains the same.
It's steady hum always at same sound level.
Doesn't increase or decrease in intensity or loudness.
 
N

N_Jay

Guest
Draw a picture of EVERY connection in your system. (each conductor, not just each wire)

Mark all grounds, then add in all other grounds.

Once you have that picture you can start seeing the complexity of trying to answer your question on a forum.
 
N

N_Jay

Guest
One more thing - sorry if this is dumb question r info - .

When I turn up the volume on my scanner - the sound of the hum remains the same.
It's steady hum always at same sound level.
Doesn't increase or decrease in intensity or loudness.
That indicates that the hum is entering the system after the point where the volume is set.

It may help pin down the issue, it might not.

Do you have a voltmeter?
 

yoopernewsman

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Messages
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Location
Negaunee, Michigan
That indicates that the hum is entering the system after the point where the volume is set.

It may help pin down the issue, it might not.

Do you have a voltmeter?
No I do not have volt meter.
Plus I probably would not know how to use it

Plus - in reference to your other answer about difficulty of answering this on forum.

You are correct in many ways - including I an true electronics neophyte.
I do not know what constitutes a "conductor" nor what is a "ground."
Therefore, I would not be able to count every conductor and every ground because I don't know which is which.

If a three prong plug represents a ground - then about half my stuff is not grounded.

Plus this hum issue happens in all rooms of the Apt. (I moved scanner even into kitchen) and hooked it into a computer with two plugs/power sources
1. Power into computer
2. Power for speakers
And still got hum.

I am frustrated because I hate to discontinue the feed but I can't take constant humming.
If only I was able to listen to scanner w/o hum - but the feed line runs from scanner's earpiece jack - and that mutes the speaker on the scanner.

Is there anyway I could do this feed and NOT have it mute the audio at the scanner?

When you get a chance listen to the Marquette County, Michigan feed and tell me if it's to annoying for people to listen to.
If hum on feed is too annoying then there is also not reason for me to make a feed.
I can not tell quality of feed because my speaker already has hum.

Bottom line if feed is OK now - and if I could still listen to audio on scanner speaker itself
That would be a solution to my problem.

But if hum is too loud/distracting for listeners - then there is no point to feeding it.
 
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