Drew, and others...

The antenna, amount of cable, and amplifier will make more of a
difference in signal quality than the type of ATSC card.  Period.  My
first recommendation is get the antenna out of the attic.  An attic is a
good place for increasing mutli path, weaking your signal, and doing the
things you don't want.  My personal experiece with my antenna was that I
could get almost no signal in my attic.  I moved it out and signals
became very clear (And I live at the base of mountains and a canyon so
I'm *very* prone to multi path).  I'm 20 miles away from the towers, use
a very low quality yagi ($20 radio shack 36 inch) run 250' of rg6,
through 2 1-4 splitters all with no amplification and get all signals
over 70% (One is 72% and another 78%.  The rest are 88+%).

True, but everything else being equal, a card with better performance will pick up a signal with lower S/N. If you're on the fringes, no reasonable antenna may be able to pick something up always... if one card is better it will work more often at least.


An additional note, not all splitters are equal.  I've found a 15 year
old cheap hardware store 1 to 4 splitter works better than a "gold
plated" radio shack one (by 7-8% signal quality loss).

Rat Shack blows goats. No surprise here. If you polish a turd with gold-plated connectors, it's still a turd.


I've found
amplifiers don't do much good for signals over 80%.

Amplifiers are overrated IMO...especially for cable Perhaps with PC-tuner cards (RF-hostile environment and all) they're more important. With over-the-air and lots of splits they are more important too... but they should also be put as close to the antenna as possible.


I've also found
that I have one HD-2k card that on 1 channel doesn't tune as well as my
other 4 cards (4-8%).  But I do know it's not a problem if I do
everything else right.  Oh, I've found every 50' of cable is about 5%
signal quality loss on signals less than 85% normally, 1% on signals
over 85%.  My HD-3k card though gets the best signals I should note.

If you want to know which card is better, I recommend you figure out
which chips they use and go do research outside of the myth community.
What I know is the hd-3k chip is much better at removing multi path than
the hd-2k.  I know that I have a lot of multi path where I am and my
hd-2k's work just fine.  I know that if you spent the time moving the
antenna outside instead of doing research, you would have better
results. :)

It's actually rather difficult since all of them have proprietary stuff on board. HD-[23]k uses Oren-brand chips. The later version in the 3k is supposed to be 1-2 generations newer than the 2k. The demod chip (can't recall the brand right now) on the Air2PC is supposed to be roughly equiv to the Oren...same "generation" if you will. From what I"ve read, the main advantage to the Air2PC is the hardware PID filtering. You don't need to stream the *whole* stream to the hard drive... only the subchannel[s] you want.


I should also note, Multi-path typically not a big issue and it
sometimes is blamed for things it's not responsible for.  You could be
getting multi path, or you could just have the frequencies bend so
slightly that it makes it between the crack in 2 shingles, or misses a
nail, or goes between two ceiling braces just right sometimes and you
get a better signal for a quick moment, or it could be MP.  If you
describe your community setting and distance from the tower I could give
you a better idea if it's MP or something else.

        RF is often voodoo.  'nuff said.  :)

-Cory

*************************************************************************
* Cory Papenfuss                                                        *
* Electrical Engineering candidate Ph.D. graduate student               *
* Virginia Polytechnic Institute and State University                   *
*************************************************************************

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