After years of fiddling with digital here as I said it either works or not , 
any installer worth his salt will install to the signal by simple  portable 
analysis test if need be ( not a cheap machine) and reliance on a web site to 
me at least makes little sense , remember treating it like analogue is a recipe 
for failure 

To: [email protected]
From: [email protected]
Date: Fri, 20 Feb 2009 13:32:55 -0600
Subject: RE: [Repeater-Builder] OT  DTV




















    
            








I find it horribly inaccurate since it doesn’t take into account
receiving height.   What height are they calculating for?  Set-top first-story
height?  Rooftop?  Tower top?  At the dirt?  I know they didn’t compensate for
the 20 ft altitude change between the end of my driveway and the front door of
my house.  

 

The exact position of the receiving antenna dictates a LOT.

 

A couple years ago, with my scanner and a telescoping antenna, I
could hear 1 UHF station’s audio at my mailbox (low, at the road)

 

Near my house, 4 ft AGL - 3

 

Inside my house,  4 ft AGL – 1 (I watched 9/11 news off this
station using set-attached rabbit ears, go figure).  Oddly enough, not the same
station that I can hear at my mailbox (this station would be very non-LOS at my
mailbox)

 

At the ‘tree line’ on my tower – 7

 

150’ up my tower – a whole hell of a lot more (all high power
stations from Tyler/Lufkin/Houston/Dallas-Ft Worth/Austin/Shreveport/Beaumont 
[within
250 miles or so]).  Some were very faint, but definitely there (and this is
with an Omni antenna and a half-deaf Uniden scanner…), some were stomped on by
local low-power stations.  The issue at that height is the antenna being
directional enough to isolate on-channel noise.

 

Now, the real question is, how bad does Fresnel affect DTV vs
analog.  I betcha you’ll have horrible problems with DTV signal in areas that
tend to ‘ghost’, where analog TV was perfectly watchable/listenable, just 
somewhat
annoying.  9901 Sweetwater, Houston, TX 77037 (house where I grew up) had this
problem.  As downtown Houston “swole” in the late 70s/early 80s ghosting became
more and more of a problem.  All we could do is kick our antenna farther west
and add a variable signal attenuator (ie ‘ ghost filter’) - didn’t help a whole
lot.

 

JS

 





From: [email protected]
[mailto:[email protected]] On Behalf Of Ralph S. Turk

Sent: Friday, February 20, 2009 8:19 AM

To: Repeater-Builder

Subject: [Repeater-Builder] OT DTV





 



Good morning All



The following is a new FCC web site for DTV



Follow instructions carefully.  Wait for the 



program to calculate info.



Seems to be one of the best.  Confirms what



I know from working in the TV business for 



30+ years.  Last several installing DTV. 





http://www.fcc.gov/mb/engineering/maps/





Ralph,W7HSG













 










 

      

    
    
        
        
        
        


        


        
        
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