On Sat, 5 Dec 2009 15:52:16 -0600, "David"
wrote:



"mm" wrote in message
.. .
I hope you guys can help me again.

I gather from posts here that RG6 is better than RG59, is
that right?

Could the use of of RG59, 33 feet, for at least one tv be
responsible for my bad reception on that tv?

I'm using co-ax for distributing tv from my DVDR to TVs
throughout the
house. (The DVDR tunes in the over-the-air digital signal
and I have
an RF modulator to change the DVDR output to analog. I
did the wiring
to the tvs 25 years ago, and I used left-over and scrap
co-ax, so the
co-ax is older than 25 years. Did they have RG-6 25 or 30
years ago?
I didn't pay attention then so I don't know what most of
it is, but
the 33 foot piece going to this one tv is RMS Electonics
Inc. 59/U.

Everything was fine until the digital conversion, and now
this tv that
I watch a lot shows a grainy picture. All the other tvs
have great
pictures, and even for this one, when I supply a signal
directly from
a set-top digital converter box, only 3 feet of cable, it
shows a perfect picture**.

Do you think replacing the RG59 with RG6 will get me the
perfect
picture other sets get? I didn't use home-runs, just
splitters and
every two splitters a signal amp, a total of three signal
amps, one
with 2 or 4 outputs, and two with 2. Would an additional
signal amp
at the start of the RG-59 also give me perfect or at least
improved reception?

BTW, I'm using an A/B switch now. I had this problem when I was
connected directly, but is there any point in getting a gold-plated
A/B switch?

Yes RG6 existed 25 years ago. You have something else wrong.
The difference in loss between 33 feet of RG59 vs. RG6 is
negligible at VHF and at most a few dB at the higher UHF
frequencies. What else is in that 33 foot span?

It's in the attic. About two feet away are two four-inch galvanized
sheet metal tubes/ducts that the bathroom fans use to blow air out of
the bathroom to the crest of the roof, but the fans are never on. The
cable doesn't go by any electric wires because the bedrooms were built
without ceiling lights. The bathroom ceiling light is maybe only two
feet away but it makes no difference if the light is on or not.

There's a 1 to 3 splitter, with one output going to another tv which
has a perfect picture, one has a terminator resistor designed for this
purpose (in an F connector), and the other output goes to the problem
tv.

The picture even from analog was perfect on most stations until analog
ended, and afaicr that was exactly when this tv picture got grainy.
But for fear this was a coincidence, I waited to ask this queestion
until I had a different tv to use here. I put that in today, and it
too has a grainy picture, even though when it was connected in the
basement, it had a smooth, perfect picture. Well, being grainy is the
only thing that's not perfect about it, afaic.


Besides being grainy, or maybe this is part of what I'm calling
graininess, the problem picture has a lot of teeny tiny white dots
sometimes just scattered in the picture and sometimes arrayed in dim
horizontal and vertical lines, about 5 lines horizontal. and 7 lines
vertical. The lines are not that straight and the vert lines move
left and right a little bit and the horiz lines up and down a little
bit. There also seem to be dots of other colors and sometimes jaggedy
dark colored lines.

The end result is a picture that's pretty good, by 1970's over-the-air
standards, and the darks are darker now than they were in June, but
it's not smooth. I can live with this of course, for years if it
works out that way, but I like to fix things.



David