[mythtv-users] Antenna attenuation guestion

Daniel cbdd at fullnet.com
Tue Jul 1 04:45:33 UTC 2008


Brian Wood wrote:
On Monday 30 June 2008 21:21:25 Daniel wrote:
   there is no such thing as multi path interference with
digital broadcast......I have three antennas on my tower pointed in three
different direction, amp on each one combined in my basement......


Say What ??? !!!

It manifests itself somewhat differently, but you can definitely have
multipath problems with digital broadcasts, especially in reflector strewn
areas like Manhattan.

beww
Multipath is a huge problem for digital transmissions which is why they have 
equalizers to remove the multipath.  If you get more multipath than the 
circuits can correct, the receiver can no longer get the signal.  If you 
have less than that, it isn't a problem.

I used to build equipment to test this stuff.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5,062,148.PN.&OS=PN/5,062,148&RS=PN/5,062,148

Allen


I do not think you understand how 8-vsb(VSB) is working
see. http://www.broadcast.net/~sbe1/8vsb/8vsb.htm..
....it is possible to have (dynamic multi path interference)  i.e.. trees in
high wind (moving objects between the transmitting and receiving antennas),
it is impossible to receive a  8vsb-modulated HDTV signal in a moving
vehicle..........

but as far as multi path interference i.e.. antenna on your house with no
trees directly in front of it......YOU WILL NOT HAVE....multi path
interference.....unless your house is going down the road or moving....if it
is flying through the air you might be allright..



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