THE BIRO TECHNICAL BULLETINS
THE DIGIAL TRANSITION - 5 MONTHS TO GO
Let us be honest. No one actually knows what is going to happen on February, 17, 2009 - the date of the digital transition. Experts having been proclaiming a smooth transition both for Cable TV subscribers as well as the 20 million non-cable, non-satellite TV viewers. But there are signs indicating that these predictions were somewhat optimistic.
Biro Engineering anticipates greater disruption in the DTV services than government agencies have acknowledged.
A typical example is the
future (Digital TV) reception of Channel 7,
The CATV system’s
150’ high antenna tower has a Channel 7 antenna installed at 100 ft above ground, receiving good
quality analog Channel 7 signals
Will the same receiving
antenna ascertain the reception of reliable, interference-free Channel 7 digital
pictures as well? Sadly, no.
Here is the problem. While the analog Channel 7 transmitter currently broadcasts with 316 kW effective radiated power, Digital Channel 7, WHDH-DT, Boston is licensed to 15 kW. This is equivalent to 75 kW analog output, representing a reduction in power of 4.2x.
Can the digital
station with such reduced power come close to replicating the service area (Grade
“B” contours) of analog Channel 7,
Projections were made and computer aided signal strength calculations performed, with testimoney supported by $2,000/day broadcast consulting engineers, but nothing can replace an on-site verification survey. This kind of testing is difficult to accomplish in September, 2008, when the digital transmission starts only on February 17, 2009.
So what are the options of the CATV head-end engineer?
While the FCC did firmly establish the February 17, 2009 deadline, the agency will also consider stations’ request to operate the digital facility with less than full power until August 2009. So even if you incur the expense to buy new antennas and relocate items on the tower, you still might not have enouh signal for 6 months! In case the picture quality further deteriorates, whom will the unhappy subscribers blame - the FCC or the Cable TV company?
Should the Hillsborough head-end engineer
indeed experience difficulties with their Channel 7 digital reception, February
The case of digital Channel 7,
(A critical note)
If you think that the
US Digital Transition starts February 17, 2009, reconsider this information. The Digital Transition
actually starts 5 months ahead, on September 8, 2008, thanks to the
The admirable objective was to ease the digital transition, discover DTV reception anomalies, and make last minute changes and modifications, if necessary.
This pioneering spirit
The stations’ 1800 ft high
transmit antennas, aided by the ground’s above average conductivity,
will produce over-optimistic signal strength readings. The
reality is that we need to know real world DTV reception
conditions and apparently this carefully selected test market does not qualify
for that. Why only
one, pancake-flat test-market? Why not three, five or more test areas in
The Cable TV industry should be on the look for fresh FCC initiatives.
For emergency engineering services:
Call: (609) 883-9866
Web site: www.biroengineering.com
PRINCETON, N.J. 08543