OTA Digital (HD) reception of 8VSB

Archived from groups: alt.tv.tech.hdtv (More info?)

"Jeff Rigby" <jffg2@comcast.net> wrote in message
news:0MWdndwR29hV7GLcRVn-jg@comcast.com...
>I hope this will be my final post on HD Over The Air reception problems. I
>believe I have tracked down the last of the problems and My TV works as
>advertised.
>
> In addition to the problems previously posted I have found that FM has
> been the major problem with my reception. The FM trap in the antenna amp
> has not been enough. With that and a FM trap between the antenna amp and
> the distribution amp most of my problems went away, except for certain
> times of the day where the TV couldn't decide to remap or display the
> actual channel and CH 40 (actually ch 52) wouldn't remap to 40 at any
> time.
>
> When experimenting to get the last of the ghosts out of the picture on
> Analog channels, I installed a bandpass splitter BEFORE the antenna amp
> with VHF being connected to a terminator resister and UHF connected to the
> antenna amp. The TV now changes channels faster and ch 40 now maps to 40.
>
> Thinking about what I had accomplished and why, I realized that FM was
> being further trapped by the UHF/VHF bandsplitter. I'd previously tried
> FM traps before the antenna amp and not had as spectacular an improvement.
> So I imagine that FM being a low vhf signal was attenuated MUCH MORE by a
> UHF/VHF band splitter than by a FM filter.
>
> Symptoms attributed to FM; slow channel change, remapping not working on
> some channels (52), sound dropouts on ch 54 and intermittent remapping
> issues (59 and 42). In addition to that, reduced amplification of
> channels thru the amp. With the FM traps installed the gain is increased
> by 30% thru the amp since FM is not being amplified.
>
> I recently purchased a ATI HD tuner for my computer and it also appears to
> be a third generation tuner as it has the same features as my TV and had
> the same problems (remap and slow channel change).
>
> I still have one problem only on the computer, channel 10 (24) doesn't
> work as well on the computer as it does on the TV and the only difference
> is an additional 50 feet of cable. Since higher frequency channels work
> well, and you would expect the higher channels to lose more signal, it
> can't be a signal level problem. CH 24 is one of the weaker before
> amplification channels so I expect that the S/N ratio on that channel is
> poor. Add 50 foot of cable and the S/N ratio probably drops enough to
> cause problems.
>
> I had none of these problems when using a 4th generation tuner on the same
> antenna system (before the FM traps were installed).
> See previous posts

Thanks for the info.

This reminds me of my experimenting with HDTV antennas back in '99.
[Northern N.J. about 15 miles from NYC]

Two different large Yagi antennas just refused to recieve PBS-HD off the WTC
in NYC.
They got all the other stations, though.
Changing to a 4-bowtie antenna solved it...all came in beautifully.
I still don't know what the hell the issue was..

We've had perfect reception [on available channels] here on 5 different 8VSB
receivers ever since.