HDTV reception dilemma.

[sammybenjamin]

I have been having a long continuous struggle with getting directional antennas to work to get all the channels I needed. They are PBS 4, CBS 5, ABC 11, NBC 17, CW 22, UNI 40, FOX 50.

I tried joining 2 antennas with some success but was not happy with the results. I finally got an Omnidirectional antenna Winegard MS2000 to resolve the dilemma of getting all the channels with one antenna.

With the omnidirectional antenna I now get all the channels I want, but some channels fluctuate from 100% to 0% in a loop and they keep breaking up. The most notorious are PBS 4 and FOX 50. Others seem to be stable enough to enjoy a smooth reception.

Is there an way to fix this issue which I think must be caused by overloading of signals that are too high. Please advise.

TVFool link: http://tinyurl.com/hdtv-27502-TVFool

[elmo]

You're likely dealing with a lot of multipathing since you have a lot of signal around you. The amplified omni directional antenna probably compounds that, hence the fluctuations you are seeing.

Tell us more about the directional antenna(s) you tried, mounts, locations, coax, trees, direction, etc. Where's the omni directional mounted?

Try a Clear Stream 2 Complete Vhf/Uhf antenna aimed at about 330 degree magnetic compass direction.

Here is how to aim antennas , http://www.kyes.com/antenna/pointing/pointing.html.

http://www.antennasdirect.com/store/...VHF-Combo.html.

Remove the Reflector Screen from the CS2 Complete antenna.

The reflector screen is not the Uhf reception loops.

The reflector screen is not the metal Vhf reception rods.

The reflector screen is a screen , remove the reflector screen.

With the reflector screen removed the SC2 Complete will receive at the front and back of the antenna.
___________________________

Do not use any type or kind of preamplifier or distribution amplifier.

Because a amplifier will make the reflected Tv transmissions (multipath) from the surrounding area , stronger. Stronger multipath is not good for Digital Broadcast Tv reception.

Also , go to radio shack , and buy a FM radio filter , and install in the coax line that goes to the CS2 Complete antenna.

Strong local FM radio transmissions can interrupt Tv reception.

____________________

As always , trees and tree leaves will , reflect , reduce , block , Digital Broadcast Tv Reception and so will buildings and other obstructions including your own roof and house.

It is best to install the CS2 Complete antenna at a location that has the least amount to no amount of obstructions of any type or kind in the directions of reception including your own roof and house.

The Tv/s Must Channel Scan for the , OTA=Over The Air , Digital Broadcast Tv stations/channels , often named the 'Air Channels' or 'Antenna Channels' in the Tv setup menu because the Tv transmissions travel trhrough yhe Air from the transmitting antenna to the receiving antenna.

Some Digital Tv's will automatic channel scan for cable tv channels.

DO NOT channel scan for cable tv channels.

Go into the Digital Tv Setup Menu and select , 'Air Channel' / 'Antenna Channels'.

Digital Broadcast Tv tuners can develop - Digital Glitches - that are not cleared out with a simple channel scan.

Do a Double Channel scan.

http://www.dtv.gov/rescan.html

[sammybenjamin]

Today I checked back my omnidirectional setup in the afternoon and it seems to have stabilized. All channels were stable between 3-4pm.

Then around 5pm the signals started to fluctuate on channel PBS 4 and NBC 17. A little while later I lost channel NBC 17 completely. At this time other channels were still OK.

It baffles me how NBC 17 @ 104 degree/20 miles is lost while CBS 5 (48) at exactly the same location and distance comes in OK (so do others in the same approximate location) ????

Later at 7pm all is well for all channels. I think that time of day and changing weather patterns affects HDTV transmissions.

I am coming to realize that HDTV transmission technology is all screwed up and has no level of consistency even when dealing with channels coming from the same approximate location and distance. It is disappointing how such poor "advanced" technology is allowed to be released to the public. They mus be hoping that most of us will have cable and will not realize how they pushed out a half baked technology to the people who do not subscribe to cable.

My 2 antenna solution produced decent results when I pointed one antenna to 104 degree and another to 270 degree. Each antenna alone produced a stronger signal for channels in its direction. When they were combined with a 3 way splitter, the over all signal strength dropped for all channels. For this reason I ventured to the omnidirectional solution to eliminate 2 antennas and the loss of signal strength.

My crusade to perfect this continues. Any advise and suggestions will be appreciated.

[Stereocraig]

You say you had better performance w/ two antennas, until you combined them.
Well then, that's the way to go.

Except this time, combine them w/ an A/B switch, so you don't suffer insertion loss and cancellation.

[sammybenjamin]

I do not with to have a manual switch to operate depending on which channels I want to see. This should all work. If anybody has an understanding o the unpredictable behavior of HDTV signals then it will help overcome them and create a stable solution.

I am going to check out some of the good information posted by user "teleview".

Thanks for all the replies and keep them coming.

[Stereocraig]

Originally Posted by sammybenjamin

I do not with to have a manual switch to operate depending on which channels I want to see. This should all work. If anybody has an understanding o the unpredictable behavior of HDTV signals then it will help overcome them and create a stable solution.

I am going to check out some of the good information posted by user "teleview".

Thanks for all the replies and keep them coming.

Teleview gives a lot of great advice.

I am receiving well over 70 channels, w/ an AB switch.

Good luck w/ that problem.

[elmo]

Personally, I don't think HDTV is bad. It's not perfect, but neither was SDTV back in 1978 either. I remember getting up to flip a channel and first dialing the rotator in for best reception. The best way to get an RF signal is to broadcast it on a wire. That's called cable, which unfortunately turned into a pig with junk programming. There's just only so much spectrum and a lot of channels to be broadcast, so it has to be rationed out and rules so that one market doesn't blow out another. I think if they wanted to push us to cable, they'd never have introduced HD to OTA. But not only did we get HD on OTA, we got the bonus of subchannels too. Antenna solutions vary from point to point. Your cell phone works great in location A and not so good in location B, which it's the opposite for your buddy on a different network. It's the nature of the antenna world. You just have to find what works best for you. For some in great markets, it's easy; others, not so easy. But the beauty is that you can spend on some good OTA hardware and maybe end up with a few left over parts, but you're done spending, vs the monthly cable bill!

There's some art and science to combining antennas; if it's not done perfectly, it's not gonna work. Think of it as trying to listen to someone with a very loud echo. The idea teleview has is to use a directional antenna (by virtue of it's reflector) w/o a reflector. You end up with a "bi-directional" antenna, which is somewhat like combining two antennas w/o the echo. That may work w/o the need of an A/B switch.

[sammybenjamin]

Thanks all for all the good information. When the reception is good, the picture is perfect and enjoyable to watch. But when it breaks up even for a few seconds, in a repeat cycle, then it destroys the whole experience of watching a show.

I am mostly pointing out to the poor stability of the HD transmission which needs to be better transmitted. It is hard to work with a situation where channels that come from the same direction and distance have different reception characteristics. Sometimes I an see an 85% signal strength, but no picture. The variation due to time of day and weather conditions affects the quality of the signal. These variations throws you off when trying to devise a solution to work around such deficiencies.

In my thinking it would have been a better planned solutions if all transmitters were located in a single TV tower which had the job of transmitting the OTA HD signals. I have seen this work in larger cities overseas.

This way the consumer is relieved of making all these directional permutations and combinations with trial and error methods to deal with its various technical nuances. In this solution, the user needs to only point to the nearest preset direction relative to their home and then fine tune the signal strength with a amplifier.

The Omnidirectional antenna is performing pretty well baring a few quirks now and then. I am convinced that this is the right type of antenna for signals that need to be received from multiple transmitters without manual intervention. This takes out the need to conjure up a complex design adaptations of multiple antennas that may require rotors and switches.

For those looking or some basic understanding of how the Antenna works, this is a good site (found it as a side link in Teleview's post):
http://www.kyes.com/antenna/antennadex.html