bud-- wrote:

On 10/31/2014 1:16 PM, Michael A. Terrell wrote:

bud-- wrote:

What is the signal voltage on cable?


I don't know about all CATV systems, but the one I did some design
work on was based on +10 dBmv at the street to all for up to four sets
per drop. +10 dBmv = 3.1623 mV.


Interesting.
I would think there would always be a lot more 60Hz noise than that.
High pass filter?


The lowest RF is channel t-7, with a 7 MHz video carrier. The RF is
transformer coupled, and the amplifiers are line powered. The pole
mounted transformers put out a 30 (Mostly obsolete by the '80s) or 60
volts AC modified sinewave from a large CVT. The main trunkline can be
up to 30 A. The hum problem in CATV is from power supplies modulating
the video as capacitors age. There is no AC on the drop to a home, but
it is possible in an apartment building or condo where a line extender
is installed in the equipment room.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.