On Fri, 06 Feb 2009 02:19:10 -0800, les wrote:


I wanted to make it a straight tuning sequence for the family, dumping
analog
forever. Using the present analog modulator has been problematic with
adjacent
band bleedover, even intermitent skip propagation from nearby cities and
perhaps
poor design of the modulator itself (I tried 3 different models). All
have performed
marginally under the circumstances. I think given the nature of digital,
interference
at least would be eliminated. We live in the Chicago area with 25 off
air channels
available, and channels 3-4 are as usual tough to negotiate via a cheap
modulator
feeding 150 feet cumulative RG-6 and active quad splitter.Several
permutations of booster
vs. splitter combinations have yeilded no significant improvement. I
contemplated a
deep notch filter, but never got into it. That's why I thought a robust
ATSC modulator could fix the issues.

Les KA9GLW

I see it looks like you really need a bunch of now obsolete MATV parts
like tunable mixers to keep sidebands suppressed and an antenna trap for
the channel 3 signal. Toobad you don't know someone who is replacing a
bunch of hotel systems that you could get the head end parts from

Without a fairly large investment it's hard to actually combine signals
through a simple splitter.

Though you can homebrew your own sideband traps fairly easily if you have
a well stocked junk box. tunable channel 3 traps are very simple just a
few turns of wire and a trimmer capacitor.

Likely somewhere they do make digital modulators but I would not want to
even think of buying one since I would guess they are currently in the
domain of broadcast equipment and we all know how inflated those prices
are.

Gnack