[opendtv] Mobile 8-VSB in the real world

  • From: Doug McDonald <mcdonald@xxxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Fri, 03 Dec 2004 12:48:05 -0600

A fellow posted about his real world, routine, DTV on the
alt.video-digital-TV NEwsgroup. With his permission I repost his stuff here:

o, I don't really see anything bad about mobile TV, I've been doing
it for 25+ years anyway.  I'll just put in my DTV receiver and
watch-a-way. as long as I'm not driving that is.  And, btw, It works.
I have a bigger inverter now, but still a small 13" color set in the
back of my Avalanche, and yeah mobile DTV is alive and well with the
USDigital HDTV receiver in mobile use.  Well, it ain't High Def, but
it works.  It does receive HD, but my little 13" ain't.  One of these
days, maybe I'll get headrest LCD's, but not for a while.  I've been
doin' it my way ... way to long!



<CaptainWatty> wrote in message

: Russ,
: What are you using for an antenna? I ahve been doing the same
: sort of thing for only 11 years or so, but never live broadcast.
: Thanks,
: Steve

It's an amplified (12v) antenna that I purchased from Radio Shack
many, many, many years ago (1978).  I couldn't tell you the model
number if I had to.  The antenna slips over the rear window, then you
roll the window up to hold it in place.  It has two dipoles that
extend out over the roof of the vehicle.  It has a selector knob so
you can "fine-tune" for the best signal.  A 75ohm coax attaches to the
vcr and from the vcr to the television.  I'm thinking about purchasing
an inline amplifier, maybe that'll extend my range 5 miles or so, see
below.  One of these days when DVD's go down in price, I'll put in one
of them <imitates old-timer> "new-fangled contraptions."</imitates
old-timer>  ;)

I'll continue with this.

With the analog signal you get ghosty, blurry, snowy images as long as
you can get a signal.  It comes and goes.  It's something you get used
to.  I've been doing this for 25+ years, and I guess that I figure
something is better than nothing at all.  When you get out of range,
you slip in a tape.  Back in the day when the speed limit was 55 mph,
it took 7 hours to drive from my house to my parents house.  I had (at
that time) all 3 Star Wars (IV, V, and VI) on tape.  My girls would
put in Star Wars and watch the whole series during the trip.  Great
babysitter!  I could get television for Dallas/Ft. Worth, Abilene,
Lubbock, Amarillo, and Wichita Falls main channels, and pull in
translator stations for the boonies around Memphis on 287 and Snyder
on 84.

With Digital, you got a perfect picture or you don't have any picture.
No snow, no fading, just pixilation and poof, it's gone.  If you know
the area, you know if you'll get it back.  If not, oh well, I
understand, and go for the tapes, or radio, or cd's.   Range is a bit
less than with analog for that reason.  (say 5 to 10 miles mobile

Just to let you know, I live in Texas... and have driven from DFW to
Lubbock and Amarillo over the past 20 years.  I receive a television
signal about the same distance you receive a normal FM radio signal.


I go out 20 towards Sweetwater and then up 84 to Lubbock.

I also go 287 towards Wichita Falls and on in to Amarillo.

And Around Ft. Worth the only real drop-outs are downtown Ft. Worth
with the buildings, but that was ALWAYS the case, nothing new to me.
An occasional drop if you go down one of the deeper ... what would you
call them, ravines, chasms, valleys?... anyway drop down a hill, but
as I said before, that's always been the rule, and It's something that
I'm used to.  Just the action is a bit different, it freezes and then
drops, before you'd get real snowy and shakey and fade away.  You
actually get a better picture longer now.



: One more question: what fraction of the distance between Ft. Worth
: Lubbock and Ft. Worth and Amarillo can you get DTV from one or
: place? The Ft. Worth stations are of course full power ... but are
: others? Does it make a difference whether they are UHF or VHF?

long reply but here goes

This was on my last trip about 1.5 months ago.
USDigital HDTV Receiver from Wal-Mart plugged into a 700 watt inverter
(just what I have).  (It (inverter) also powers lap-top and other
electronics as necessary.)  Amplified (12v) mobile diapole from Radio
Shack that is >25 years old using 75ohm coax.  13" RCA CRT 120/12v
color set using composite video / ausio in for DTV, built in tuner for
analog.  (no splitter, manually change antenna from STB to TV if
changing... better for both analog and digital if no splitter in
mobile install... I've tried it, I know.)

Ditital Stations listed only

West on 20

near DFW
27 and 58 are the worst... only available to intersection of I20 and
I30 west of ft worth.  (Aledo Hill)
ABC (VHF) next fades out about Weatherford.
Fox, CBS, NBC, WB, UPN, PBS stations are last to go about the Parker
County line.  some 30 miles west of my house.  This is about 10 miles
before the analog signal gives up the ghost.  But, it is really in and
out by now anyway.

Near Abilene
You can pick up NBC and CBS about Cisco. (Abilene Stations) and ABC
and UPN come in as you enter Abilene (Sweetwater stations).  NBC and
CBS leave about Sweetwater, while ABC and UPN stay in until Snyder on
US 84

Near Lubbock
PBS, FOX, NBC come in as you top the hill at Post and stay in until
after you turn north on US 385 outside of Littlefield.

Near Amarillo
West Side up us 60 from Hereford
Can begin picking up CBS and PBS (both VHF) near Umbarger,  Fox and
ABC (UHF) come in near Canyon.
East Side
FOX and ABC cut out just past Claude (US 287) while CBS and PBS last
almost to Clarenton.

Near Wichita Falls
East Bound on 287
CBS, NBC, ABC, and Fox all come in as you near Iowa Park.
West Bound 287
CBS, NBC, ABC, and Fox all come in as you near Bowie.

Hope this helps


What this seems to mean, looking at maps and the FCC
database, assuming that stations with an STA are using them,
he gets about 55 miles on a full power VHF, 45 on full power
UHF, the Ft. Worth stations. Note that he actually lives
about 30 miles away from their 1700 ft HAAT towers.

He sees to be getting about 15 miles for low power UHFs.

This is with the antenna he describes, rather low to the car.

This is about what I would expect. It's true real world
experience in the Heartland of America.



Doug McDonald
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