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                      THE CGC COMMUNICATOR
                            CGC #890
                  Wednesday, February 18, 2009
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                Robert F. Gonsett, W6VR,  Editor
                <cgc (at) cgc333.connectnet.com>
    Copyright 2009, Communications General® Corporation (CGC)
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  THE SAN DIEGO DTV TRANSITION IS GOING SMOOTHLY
  Early reports indicate that the partial DTV transition
in San Diego, CA is going well with fewer than expected viewer
complaints.  It appears that San Diegans were well prepared
for the changeover.
  Last night's switch went as predicted in CGC #889.
The major stations that did NOT shut off analogs were
KNSD (NBC), KUSI (IND.), KPBS (PBS) and XETV (CW).  Analog
service was shut off at KFMB (CBS) and KGTV (ABC) while the
analog signal at KSWB (FOX) was repurposed as a "night light"
to provide looped DTV transition information for the public.
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  SEE THE END OF ANALOG ON U-TUBE
  KGTV had the foresight to do a live news shot from their
Mt. Soledad transmitter at about 11:30 PM yesterday when they
switched off their analog transmitter.  Someone recorded and
posted this historic video on UTube, and you can see it here:
  http://tinyurl.com/KGTVEndsAnalog
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  THE 10 AM (FEB 18) REPORT FROM CHANNEL 10, KGTV, SAN DIEGO
  We have had surprisingly [few] problems with the transition.
Pat Givans (Dir of Technology) and I have received a steady stream
of emails from viewers who are having reception problems.  Most of
these are due to viewers needing to rescan their channels to re-
memorize channel positions.  Some are because they may not have
VHF antennas hooked up to their receivers.  Others closer in to
the center of radiation are probably due to too much signal.
We are double checking our power output levels, but according to
field strength readings, it looks like we are right on target
to our licensed power.
  Lots of work to do still to complete the transition both
in the studio and at the transmitter, but the big ticket item
is done.
  Andrew Lombard, Chief Engineer, KGTV, San Diego
  P.S.  We are dispatching an engineer to special needs
people's homes to give them a hand on a case by case basis.
Obviously we aren't set up to handle everyone's problems, but
we may be able to make a difference for some.
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  CGC ASKED: WHO PUSHED THE ANALOG "OFF" BUTTON AT KGTV?
  KGTV's Andrew Lombard replied, "That was our senior
engineering statesman Jose "Frank" Cruz.  He and Matt Schiller,
who we call "Junior" because he's the youngest in the engineering
department, did the transmitter reconfiguration on the analog
transmitter to flip it to digital.  So we had a little poetry
with the oldest member and the youngest doing the work.  Sort
of a rite of passage for engineers.  We have had surprisingly
little problems with the transition."
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  NEWS BRIEFS
  o  Story of interest from Broadcasting & Cable magazine:
  http://tinyurl.com/BcArticle-2
  o  General HD comments at the "HDTV for San Diego" site:
  http://tinyurl.com/HDTV4SD
  o  David Tanny's "San Diego Radio News" is also covering
  the HDTV transition:
  http://www.sandiegoradionews.com/0100.htm
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                    DTV LETTERS TO THE EDITOR
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  PREDICTING DTV RECEPTION
  This concerns the lead story in CGC #889, "New FCC Computer
Tool Predicts DTV Reception".  With mixed feelings, I entered
the coordinates of my house.  It found my house correctly, and
correctly estimated my altitude.  Its output channels are far
more accurate than tvfool.com, and far easier for the
uninformed to read.
  However, it doesn't get the diffraction correct, erring on
the liberal side, showing me channels I cannot receive to the
East, but that isn't surprising, as the topography here defies
all common diffraction algorithms.  The gain-loss map available
by clicking on a call sign is helpful and scales nicely, though
it is based on Longley-Rice and is also not terribly accurate,
as it ignores all elevation pattern data....
  Thanks Bob, as always, for your dedication in providing this
information.  It surprises me that no one has imitated the CGC
Communicator for other areas -- too much work probably.
  (This letter is from a well known professional software
  developer for consulting radio and television engineers.
  Because of the flood of HDTV news, the CGC Communicator
  did not have time to clear his name for publication.)
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  HOW DOES THE PROGRAM WORK?
  Question:  Re "FCC Computer Tool Predicts DTV Reception"
in CGC #889....  may I ask what is "under the hood?"
  Answer (from a Washington source):  The propagation loss
engine is ILLR with coarse (1-kilometer) terrain extraction.
The weak signal condition is the usual, noise-limited value.
The moderate and strong signal conditions are +15 and +35 dB,
respectively.  Interference isn't considered.  Geocoding
and mapping are done through a link to Google.
  http://www.fcc.gov/mb/engineering/maps/
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  A VIDEO PROMOTING DTV
  Through underwriting from the IEEE Broadcast Technology
Society, Gary Sgrignoli and I were able to create a [video]
program called "Receiving DTV" which we have made available to 
any stations that want to use it as part of their education of
their over the air viewer.  The program is available for
viewing at the URL below.
  Any station that would like a copy of the program should
send me an e-mail request.
  William T. Hayes, Director of Engineering and Technology
  Iowa Public Television, hayes (at) iptv.org
  http://tinyurl.com/NewDTVSigProgram
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