[SBE] analog shut-off day

[Spain Robert]

A big problem with low band DTV is the high noise floor - and 8 vsb decoders can't deal with that. Ignition noise, arcing neon lights, cracked power line insulators, lightning are much worse at low band than high band or UHF.  Problem #2 is rabbit ears - at best, they are a half wave dipole, with 0 db front to back ratio, picking up reflection from mirrors, refrigerators, etc.  At worst, they are pushed all the way in, and resonant on channel 13; oriented the direction the tv sits, not towards the TV station tx.  
The rural viewers in your grade B contour don't use rabbit ears - they use real antennas, that have front to back ratios, and minimum multipath.  
In Casper, we had to use a channel 47 DTV translator to feed the DISH network receive point, because the receive POP was 1000' from a substation.  The noise floor from that substation is so high, the s/n from our VHF DTV tx was only 16 db.  The s/n from the channel 47 (10 watts into a PR-450) was 30 db.
We have been fighting with the utility for years, and they won't do anything.  

Bob Spain 
Wyoming PBS 





-----Original Message-----
From: sbe-bounces at sbe.org on behalf of Gibson Prichard
Sent: Sun 6/14/2009 9:46 AM
To: sbe member discussion mail list
Subject: Re: [SBE] analog shut-off day
 
WTVF Nashville moved from UHF56 digital to VHF5 12am on 6/12 and has been
deluged with viewer calls. Things like poor indoor antennas, no knowledge of
re-scanning, boxes that hold our pre-transition channel position (and won't
update it to the post-transition freq.) are only the tip of the iceberg. We
figured a move to low-band 5 would be beneficial to the distant viewers who
couldn't pull in 56 due to propogation issues. We had no idea the near-field
would be as big of a deal where we have loads of signal and are even
circularly-polarized.
We've probably had in excess of 2000 calls and not seeing any real solution
to what largely seems to be problems relegated to viewers less than 40 miles
from our tower.

Gibson

On Fri, Jun 12, 2009 at 9:17 AM, <chscherer at everestkc.net> wrote:


> Any stories of problems as stations turn off their analog transmitters? I'm

> not asking about the station's ceremony (if any), but rather any viewer

> problems? Are the predictions of unprepared viewers proving to be true?

>