Pixilation

MCH13 · 18-Apr-2012, 10:58 PM

New to OTA. We installed a new Winegard HD 7694P. Presently operating two TV's. We are getting intermittent pixalation on every channel about every minute or so. We are getting full signal strength (full bars) with or without an amplifier. Below is TVfools report. Any feedback and suggestions on how to resolve pixalation would be greatly appreciated. Thank you.

http://www.tvfool.com/?option=com_wr...0b8640c00f51a4

signals unlimited · 18-Apr-2012, 11:48 PM

Pixalation with full bars is nothing unusual. With the signal strengths at your location your antenna is choice is "spot on", however untill you resolve the interferrence I would keep the amplifier out of the picture.

Interferrence usually comes from one of two sources: unwanted out of band communications signals, or electrical. Since your problem is across the entire spectrum (broadband) and all communications signals are narrow band, it is more likley electrical. This can be from inside your home or something in your neighborhood.

Some suggestions for inside:
Shut off any florecent lights, dissable any remote phones, modems and all other wireless devices. Try powering your equipment from a different electrical circuit. also if possible you could try turning off circuits in your home (one at a time).

Outside electrical can come from a bad ground in the power grid (transformer ECT), or if you are in farm country an electric fence. This can be a little tricky to resolve. Hopefully the tips that I have provided help you resolve the problem, and other experts on this blog will chime in if they have any ideas, interferrence or otherwise.

No static at all · 19-Apr-2012, 12:13 AM

Do you live near LAX? Could be airplane induced interference.

Have you ever fine tuned the antenna to make sure is aimed properly? Also, the narrow end of the antenna should be aimed at the transmitters. Some tuners will give full strength readings even with the antenna mis-aimed.

GroundUrMast · 19-Apr-2012, 2:08 AM

Both ideas top my list of suspects... That is, interference generated by appliances and electronic equipment in your home, and aircraft induced multipath.

http://flightaware.com/live/airport/KLAX shows arriving commercial aircraft flying over the Culver City area which then turn 180° to fly the final approach into LAX. There is also a corridor for general aviation over the Culver City area.

To fight the interference caused by signal reflecting off aircraft, try moving the antenna to a location that has a clear view of Mt. Wilson but is 'shaded' by an eve or carport roof. The goal is to block the signal reflected off the aircraft, while still receiving a strong direct signal from the transmitter. Tilting the nose of the antenna may also help, though the clamp assembly on that antenna may not give more than a few degrees of range.

Your TVFR clearly shows you have no need for any sort of amplifier. With the signals as strong as indicated and the gain provided by the HD7694P, you should have no problem supplying as many as eight tuners using only a passive splitter.

Electron · 19-Apr-2012, 3:43 AM

Aim the antenna at about 65 degree magnetic compass. Here is how to aim antennas , http://www.kyes.com/antenna/pointing/pointing.html. The Tv transmissions are Very Strong at your location. Move the antenna to find a location outside the house that uses the house to block the Tv signal reflections from the airplanes. This will mean having the antenna lower to the ground.

MCH13 · 19-Apr-2012, 5:31 AM

Antenna is installed on the roof of our single story house. According to installer it is properly aimed towrd Mt. Wilson with narrow end aimed at the transmitters. Installer confirms that antenna clears roof of our next door neighbor's two story house with no obstruction. Installer's position is if antenna was not properly aimed and/or did not clear next door neighbor's roof we would not be getting full signal strength (full bars) as we are now thereby ruling out any improrper antenna direction or nearby building height obstructions.
Does full signal strength read on tuner actually proove that antenna is unobstructed and correctly aimed?

We are no where to close LAX flight path. According to member "Electron" antenna should be aimed at 65 degrees. Is this a typo as it was my understanding fin speaking with all professional that antenna should be aimed at 45 degrees? What's strange is that pixilation occurs about every minute on every channel. Before I attempt to rule out any electrical interference as that will be a very difficult and tedious task I would greatly appreciate any and all follow-up feedback. Thank you.

Electron · 19-Apr-2012, 8:01 AM

The groups of Tv stations to the north/east , east . 65 degree is in the middle of the groups of Tv stations. Standing on the ground at your location , LAX seems far away. Looking down from the sky , your location and LAX , are next door neighbors. Airplanes have metal bodies , the metal bodies make great reflectors. Tv tuners do not like reflected signals that move. The advisors here at tvfool are providing likley situations/causes of disrupted Tv reception. Turning a Tv antenna to the left and right can some times find a position that clears up reception. Moving the antenna to different location can clear up reception.

MCH13 · 19-Apr-2012, 1:01 PM

Thank you Electron. but would you please comment on previously posted and following question "Does full signal strength read on tuner actually proove that antenna is unobstructed and correctly aimed?". If not would you please elaborate. Thank you.

GroundUrMast · 19-Apr-2012, 4:17 PM

In your situation, there may be enough signal power in the air to drive the signal meter to maximum indication even when the aim is not "perfect". So, while the signal meter is a useful aid, my advise is to resist the temptation to fixate on it.

At this point, reliable video and audio are the best indication of correct antenna selection, location and aim.

Electron · 19-Apr-2012, 4:44 PM

The answer is Yes , However , the signal strength at your location for most of Tv stations is so Strong that the signal strength meter will likely read full strength no matter direction the antenna is aimed. HOWEVER using the Pending Applications Included as a reference there are some weak Tv stations/channels in the red reception zone that you can use to test the reception by turning the antenna , KTBV , KNBC , KVEA.

mtownsend · 19-Apr-2012, 6:12 PM

Just for reference, here's a virtual representation of where the transmitters are on Mount Wilson (green dots on top of the mountains). This is an approximated view in Google Earth from your location. On a clear day, this might help you visually inspect your antenna to see if it's pointed in the right direction.

Note that with your antenna, a +/- 20 degree aiming error is probably not going to make much of a difference (your signals are strong and your antenna has a relatively wide beam width).