How do I build a simple parallel (tank circuit)/notch filter?

CDRIVE

Joined Jul 1, 2008
2,219
I did try the meter that I have and it would not settle on a number. It is a digital meter. I figured it was not good enough to do the job so I order a meter that will read up to 20M. Did I do the right thing?

Thank
That's not a good sign. It would seem to indicate that the noise is quite substantial. Put the meter on AC volts and measure again.
 

CDRIVE

Joined Jul 1, 2008
2,219
I determined that the hum is around 1000 KHz by going to an online hearing test site and comparing a 1000KHz sound to the hum on the phone line.
Ouch! We should have asked you what this "HUM" sounded like right from the get-go. Here's are some very important questions..

What kind of Internet connection are you using?
Do you have a LAN. If so, what type?
Is your phone in a house or apartment?
 

Thread Starter

yeto

Joined Jul 3, 2011
12
Ouch! We should have asked you what this "HUM" sounded like right from the get-go. Here's are some very important questions..

What kind of Internet connection are you using?
Do you have a LAN. If so, what type?
Is your phone in a house or apartment?
I have two internet services. Verizon Wireless MiFi2200 and cable.
I do not have a LAN.
The phone is in a house.

I can go to the outside phone box and plug in a phone and I get the same hum so I am convinced it is originating on the phone companies side.

Thanks for trying to help me figure this out,
yeto
 

CDRIVE

Joined Jul 1, 2008
2,219
I need to sleep on this because it is not even remotely common to have a 1KHz tone on your line. I thought you were describing 60Hz hum, which would be more common.:confused:
 

ifixit

Joined Nov 20, 2008
652
Hi yeto & CDRIVE,

The 1KHz tone, if you're sure that is what it is, cannot be flitered out as it is in the middle of the telephone operating band (voice band). Instead, you have to fine out where it is coming from and eliminate it at the source. If it comes from the phone company line then they will have to do it, since you (yeto) cannot.

Regards,
Ifixit
 

Thread Starter

yeto

Joined Jul 3, 2011
12
I think my math is wrong. I was calculating for a 1000 KHz hum instead of a 1 KHz hum. No wonder the tank circuit did not make a difference.

I am going to order the parts to make a 1 KHz tank filter. I am stilling waiting on the new 20M ohm meter to arrive so that I can take some new measurements at the phone box.

Thanks for all the help,
yeto
 

CDRIVE

Joined Jul 1, 2008
2,219
Hi yeto & CDRIVE,

The 1KHz tone, if you're sure that is what it is, cannot be flitered out as it is in the middle of the telephone operating band (voice band). Instead, you have to fine out where it is coming from and eliminate it at the source. If it comes from the phone company line then they will have to do it, since you (yeto) cannot.

Regards,
Ifixit
Curious why you included me in your quote?
If you read this entire thread you will find that at no time have I suggested filtering the offending noise.
 

CDRIVE

Joined Jul 1, 2008
2,219
I think my math is wrong. I was calculating for a 1000 KHz hum instead of a 1 KHz hum. No wonder the tank circuit did not make a difference.

I am going to order the parts to make a 1 KHz tank filter. I am stilling waiting on the new 20M ohm meter to arrive so that I can take some new measurements at the phone box.

Thanks for all the help,
yeto

yeto, 1000KHz = 1 MegaHerts. You couldn't possibly hear that frequency anyway.

Who was the tel company rep that told you they couldn't do anything about this problem? Was it a repairman? I suggest that you stay on their butt until they fix it. Masking the problem is not the logical solution.

BTW, when you tested at the outside jack box I assume you unplugged the house connector and plugged your phone in directly?
 

ifixit

Joined Nov 20, 2008
652
Curious why you included me in your quote?
If you read this entire thread you will find that at no time have I suggested filtering the offending noise.
Hi CDRIVE,

Sorry, didn't mean to imply anything. I thought, since it was just jumping into the conversation, that I'd say Hi to both of you.

I don't thing yeto has read my post (#25) yet. From post #26 it sounds like he is going to try and filter out the 1KHz tone anyway:confused:. He must know something we don't.

Regards,
Ifixit
 
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