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Forum Archive Home -> Digital TV -> HDTV - Adjusting Antenna for better reception



HDTV - Adjusting Antenna for better reception
vhelp posted 2006 Jun 03 00:03
Hi everyone :lol:



HDTV Receiver and Antenna

To be short, This past week (wed) I was playing around with my Antenna and
re-tuning into the HD channels of my receiver, when all of the sudden, I
was getting THREE times the channels I normally get.

Ok, the long story

Normally, I only get one major channel, (ABC) and I was fine with it for the
time being. But, on Wednesday night, I could not get it in properly, as it
would break up and pixelate. To my knowledge, weather was good.

I unpluged my Receiver for several minutes while I did some preliminary moves,
as depicted below.

So, I decided to fiddle (quickly) with my Antenna in my other room. As it
turned out, I found another block that raised my antenna another 3" off the
bedroom floor. Then, I turn the antenna another inch or two, and proceeded
to re-tune ALL the channels again from scratch. This clears all channels
to zero and starts all over again - in theory, at least. Anyway.

While the Receiver was tuning (searching) for new channels, (normmaly, I get
only 27 [ @ 5 ch's ], and 48 [ @ 2 chn's ], but all of the sudden, I was
stunned and surprised to see a slew of channels I never seen before, pop up
onto the screen (like x-mass tree lights) and I could not control my excitement.

By now, I was getting CBS; NBC; FOX; PBS; i; PAX; and many many more, totalling
to 30 channels :)

But, all of these channels lasted for some good TWO to THREE hours, before I lost
the major ones, CBS; NBC; FOX; and PBS (to my knowledge) to some unknown cause.
Its a mystery. I did nothing else to the Antenna.

Another attempt to fine-tune in those channels

Today, (this evening) I made another attempt to get those channels back, but to no
avail. On my receiver, the meter level would not budge, except for the old channels,
27 and 48 respectively.

Ok, so, I have theories of my own, as to what might have caused the disapearance of
all those channels, but I'll wait in hope for some explanations, here.

QUESTION:
** How do I adjust my antenna according to the chart from www.antennaweb.org ??
** I don't understand this degree business. Can someone explain more clearnly ??

The specs:

** Antenna: Radio Shack brand, VU-75XR VHS/UHF/FM
** The pie chart states, GREEN and 75 mile range
** HDTV Receiver: by Hisense, USDigital
** most channel distance from me are 41 miles or less

Thanks in advance.

-vhelp 3960



edDV posted 2006 Jun 03 00:54
I found this pattern for the VHF stations for the VU-75. For DTV(SD and HD) you would mostly be looking at UHF stations. I overlayed an antennaweb station direction graphic.



Stations H,I,J,K are on the strongest lobe. A,B,C,E may work off the side lobes. G and F would be fairly strong off the back . D would be the weakest.

Normally you point the antenna to the weakest of your desired stations (factored by distance and transmitter power). In some areas, DTV stations operate at different power levels during the day. This is more likely in small markets.

The UHF pattern is more likely to be focused forward. That antenna looks too small for 75mi.

http://www.hdtvprimer.com/ANTENNAS/comparing.html
http://www.hdtvexpert.com/pages/antout.htm
http://support.radioshack.com/support_video/doc38/38046.htm
http://support.radioshack.com/support_video/doc61/61153.pdf



redwudz posted 2006 Jun 03 01:17
I've found with my HDTV antenna that changing the vertical angle can help. It usually sets perfectly vertical. But if I angle it up a few degrees, my signal improves. It depends on how high the transmitter tower is compared to your location. If your antenna has a narrow 'focus', then it is more critical. If the antenna is inside like mine, you have to watch for metal in your walls also, as that can throw off reception. I have also noticed that you want to 'Overkill' on your antenna specs as most of them seem to be rated way too low. Digital is different than analog. If the signal isn't enough, it just ignores it. You have to have enough signal strength. I use a amplifier, even with close HDTV stations.


vhelp posted 2006 Jun 03 02:11
I know its pretty late, even for me, but I just wanted to add.. before
I sign off..

The weard part of it all, was on that night, when I was tuning in for
the channels, the "search" was rather quick, and channels were like,
just pooring in. I only wish I had recorded all the channels numbers
that was on my unit's memory, so that I least I know which channel(s)
to aim for.

But, for what its worth, I had multiple NBC; CBS; PBS; and PAX; stations.
I recall having an NBC-SD (sd specs) and NBC-HD (hd specs) and the -SD
one was obviously analog and fullscreen, while the digital was more clean
and widescreen.

The other weard thing, is that I can't find those channels anymore. Its
like they dissapeared with no hint of meter movement for any of those
channels. So, something did happen, but I'm not sure what. I just don't
buy that stations shut off or drop there power rating, though I think that
I lost those channels around 11pm, that wednesday night. I'm wondering if
it was a wednesday thing, and that I cought it by coinsidense. If I don't
make any headway tomorrow, I'll keep at it for the rest of the week and
on through wednesday. If anything, at least I'll know if it is something
consistant and only a wednesday thing. If it turns out to be a wednesday
thing only, then my question would be, WHY ??

Right now, my head hurts too much from all this investinging work.

Later on today, I'll try more antenna adjusting and re-searching for new
channels again.

Appreciate the feedback, guys :)

Ooh, almost forgot..

I was in error, earlier. My antenna is 50 miles UHF and 75 for VHF.
Still, I don't think that antennas spec is at fault here.

-vhelp 3962



lacywest posted 2006 Jun 03 02:43
I use a antenna on my roof attached to my chimney ... I am really happy with the channels I'm getting ... I am using the Directv HR10-250 to feed in the HD channels from my outside antenna.

Can you mount an antenna on the roof ... ??? ... It is worth it ... for sure.

Zip code is 93230



Richard_G posted 2006 Jun 03 02:54
It was almost certainly caused by anomalous propagation due to the weather and/or atmospheric conditions. A localised area of high pressure can cause this but would normally last for longer than a couple of hours. The most likely thing would be a temperature inversion causing a 'duct' to open within the ionospheric layers.

What happens is that, for whatever reason, the layers in the ionosphere change density and this alters the refractive index. The radio signals, instead of simply passing through these layers, being refracted slightly as they go, get trapped between two layers. This allows the signal to travel much further than they would under normal circumstances. When it happens in the UK, we get other stations from France and Spain, at least the extra ones you got were in the same language!.

See here http://en.wikipedia.org/wiki/Atmospheric_ducting



painkiller posted 2006 Jun 03 05:55
To vHelp:

As for your concern about the "degree business" - when I had a rotator installed on my outside antenna the installer had to orient the antenna first towards magnetic north. Then tighten connections/bolts to the rotator.

Inside near my tv, the dial allows me to then point the antenna in any direction at various degree marks.

That antennaweb.org site should also tell you what channels/stations are available in your area.



vhelp posted 2006 Jun 03 13:42
I think that there are so many "weirdness" in these HDTV Receivers these days.
I mean, I find that there are lots of Bugs; Hidden Tweaks/Buttons; and other
things, enough to keep you curiuous; hunting; and busy; for a while.

Anyway. I'll post as I find more things out.

-vhelp 3966



vhelp posted 2006 Jun 03 14:14
** HOW TO HARD RESET YOUR USDIGITAL HDTV RECEIVER UNIT **

( I have found, yet another method to *reset* this unit. Don't know if it will
work on every model, but it you own one of these units, and feel it might be
helpful to you, give it a shot. )

(This procedure will *reset* to factory default, including clearing channels)

(also, YMMV - your mileage may vary)


1 -
:

Here's how:

    1. Press "guide" (the USDTV guide - a red oval button on my remote)
    2. Press "aspect"
    3. Press "exit"
    4. Press "prog info"
    5. Press "0"




2 -
:

If done properly, (keys pressed w/in 1 sec apart) you should see the unit
blank out and back into the initial stage, with a large YELLOW USDTV logo.




3 -
:

Then, the unit will present you with a blue WELCOME screen followed by a message:

- Press "OK"




4 -
:

After that, you will be guided by the screen prompts (be sure to read)
in order to setup the HDTV Receiver from scratch again.

(note, if you had received (via purchase) one of these units and first plugged
it in, and you did not get the above message from step 2 onward, then chances
are, you got a re-packeged unit from the store, or manufature did not run this
hard *reset* procedure before leaving their fix-it warehouse - just a theory)



-vhelp 3967



edDV posted 2006 Jun 03 14:32
VHelp,

If it were me, I'd use antennaweb.org to locate the probable channels, their direction and distance. Then I would manually program those into the box. Then I would fiddle with aiming the antenna to get the most stations.

If the stations are located in different directions, then multiple antennas with a combiner or a rotating motor will be required.

This is so 1950's :-)



vhelp posted 2006 Jun 03 15:06
edDV,

probably is 1950's, but..

That's not the problem -- I already thought of that, believe me.

The problem is that this unit does not feature that ability -- to manually
store chan numbers. If I knew how, I would :) and so far, I have not been
able to find any links to related USDIGITAL hacks/hints/tips on this, among
other things :roll:

Actually, I was investigating this very idea, through random button presses
on the remote, but no success as of yet.

I'm still investigating various ideas with my unit and antenna.

Also, I'm still in the quiet house regarding degrees and things. My antenna
is an.. wait, you already know what kind it is. Anyways, you do realize
that I have it inside. And, the fact that it is not outside does not seem
to make any difference, to my knowledge. But even so, I can't have it out-
side because i'm in an apartment, and there are restrictions, etc. So, I
have to live by my witts through hacks and tricks and things.

( try not to judge me so harshly or negatively -- not everyone is so
fortunate as you, you know )

But, thanks for your input,
-vhelp 3968



edDV posted 2006 Jun 03 16:04
Not judging, just trying to help.

Inside performance depends on how much metal is in the walls. Modern buildings use metal as a vapor barrier.



As for manual channel programming, try the AVS forum. Somebody will know how.

If you only need to tune UHF there, there are more compact alternatives. Look for flat panel models that can be installed at windows or on the deck. The FCC has ruled that apartments cannot prohibit antenna solutions for DTV. This can cause a drawn out battle though.




http://www.ksaudiovideo.com/ppf/P_ID/233/PT_ID/184/product.asp













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