Humming sound

[Eric Lipkind]

All of a sudden in the last week, when watching live TV or a TIVO recording,
there is a humming noise in the background coming out of the speaker of the
TV. If I watch a show that was recorder prior to this, it sounds fine, so
its not the TV. I do not have this problem on any other TV with cable.

Could it be the TIVO box all of a sudden causing some type of distortion?
Thanks.

[Dave Platt]

>All of a sudden in the last week, when watching live TV or a TIVO recording,
>there is a humming noise in the background coming out of the speaker of the
>TV. If I watch a show that was recorder prior to this, it sounds fine, so
>its not the TV. I do not have this problem on any other TV with cable.
>
>Could it be the TIVO box all of a sudden causing some type of distortion?
>Thanks.

This sort of a hum often indicates a "ground loop", caused by improper
or faulty or inadequate grounding of a cable-TV feed. If the cable is
not tied to the house's grounding system, voltage differences can
appear between the cable's shield (probably grounded out at the power
pole) and the TV/TiVo/stereo system (grounded through the house
wiring, to the building ground-stake). The voltage difference can,
and often does appear as 60-cycle audio hum in the signal.

Have there been any changes to your power wiring setup, or have new
TVs or other devices been hooked up to your cable-TV coax recently?

The usual cure is a "ground loop breaker" or "hum bucker" - a 1:1
RF isolation transformer, installed in line with the cable-TV coax.
It passes the RF through, but provides a high degree of electrical
isolation at the 60 Hz powerline frequency, and interrupts the ground
loop.

--
Dave Platt > AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[Dave Platt]

>All of a sudden in the last week, when watching live TV or a TIVO recording,
>there is a humming noise in the background coming out of the speaker of the
>TV. If I watch a show that was recorder prior to this, it sounds fine, so
>its not the TV. I do not have this problem on any other TV with cable.
>
>Could it be the TIVO box all of a sudden causing some type of distortion?
>Thanks.

This sort of a hum often indicates a "ground loop", caused by improper
or faulty or inadequate grounding of a cable-TV feed. If the cable is
not tied to the house's grounding system, voltage differences can
appear between the cable's shield (probably grounded out at the power
pole) and the TV/TiVo/stereo system (grounded through the house
wiring, to the building ground-stake). The voltage difference can,
and often does appear as 60-cycle audio hum in the signal.

Have there been any changes to your power wiring setup, or have new
TVs or other devices been hooked up to your cable-TV coax recently?

The usual cure is a "ground loop breaker" or "hum bucker" - a 1:1
RF isolation transformer, installed in line with the cable-TV coax.
It passes the RF through, but provides a high degree of electrical
isolation at the 60 Hz powerline frequency, and interrupts the ground
loop.

--
Dave Platt > AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!