Question: Pixelation and Signal Loss is Worse Outdoors

JBatch

DTVUSA Jr. Member
#1
I am looking for assistance to help resolve some pixelation and signal loss issues, and also to try to understand why I am getting higher signal strengths with my antenna placed indoors compared to my antenna placed outdoors.

My zip code is 22304 (Alexandria, Virginia) and my TV Fool report is located at:
TV Fool

I live in a third-floor apartment (of a four-story apartment building) facing North (in the direction of the DC broadcast towers). There is another four-story home directly across the street between my apartment and the broadcast towers, so I do not have direct line-of-sight to the broadcast towers. And since I live on the third floor of a four-story building, mounting the antenna on the roof is not an option for me.

I am currently using a Winegard Freevision FV-HD30 antenna mounted on a Winegard TR-2000 tripod attached to a DTVPal DVR with about 25 feet of RG6 coax cable.

When I put the antenna indoors facing a window pointed North toward the broadcast towers, I get signal strengths between 75-85 on all channels (both VHF and UHF) about 90 percent of the time. However, I frequently get brief pixelation and intermittent signal loss on all channels (both VHF and UHF) about 10 percent of the time. This appears to occur at all times of the day, in all weather conditions.

To try to clear up the pixelation and signal loss issues, I moved the antenna and tripod mount onto the balcony. However, the signal strength dropped from 75-85 indoors to 65 or less outdoors on all channels, no matter where on the balcony I placed the antenna. The balcony does has a metal railing, so that MIGHT be part of the problem. I tried raising the antenna above the height of the metal railing, but the height of the antenna did not appear to have any impact on the signal strength.

When I moved the antenna back indoors by the window, the signal strengths jumped back up to 75-85 again. I even tried opening the window in front of the antenna to see if that would make any difference. But the signal strength dropped again from 75-85 with the window closed to 65-75 with the window open.

Does anyone have any suggestions on what I could try next to try to eliminate or reduce the pixelation and intermittent signal loss? Moving the antenna outdoors only seemed to make the signal strength worse and did not resolve the pixelation or signal loss issues.

Thank you,
JB
 

EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#2
Is your building brick? Is the building across the street brick?


What you are suffering from is known as multipath.

You dont have a direct line of site to the towers becasue of the building across the street. You are receiving reflected (and refracted) and everything in between signals. As such that is why location is so important. Moving the antenna around and seeing how it reacts is good. The best location you found is where a sweet spot of reflected signals is. You have good signal strength to the TV with your antenna system and location, however now you have to combat multipath.

How do you do that?

One way with the antenna that you have is to rotate it left and right and try to put the offending signals in the nulls of the antennas, while locking on another still in its polar pattern lobe. This will be trial and error with no guarantee of success. Signals could be bouncing all around there from different directions (and likely are)....but its necessary to continue forward...and you will have to come back to it, if it doesnt solve your problem with your current antenna.

If this doesnt solve your problem, then you need to get an antenna with a higher F/B Ratio and a Tighter Beamwidth.

Some good bets...

Terk HDTVi
RCA ANT751/EZ HD


The Terk has a pretty tight UHF section and you can work the VHF Rabbit Ears into a tightening pattern or aim the nulls on VHF however its not very directional nor does it have a high F/B Ratio on VHF.

The RCA ANT751 is larger, has a higher F/B Ratio VHF section (and higher gain) than the Rabbit Ears and slightly less performance on UHF than the Terk's log periodic but still some directivity to work with.

It will still take some trial and error. You should buy from a place with an easy return policty.

Try the Terk First.

Hope that helps.
 
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#3
I agree with EV about this being a multi-path issue. It seems you've gotten a "hot spot" in your apartment.

When you tried the antenna outside, did you mount it vertically? Did you also try laying it flat?

Grabbit Ears (homemade-small like yours) under-perform outdoors when kept in the vertical as I use them indoors. When placed flat outdoors, their performance is far superior to inside placement.
 

JBatch

DTVUSA Jr. Member
#4
Thank you for your comments and suggestions.

Is your building brick? Is the building across the street brick?
The side of my building and the side of the building across the street facing my apartment both have vinyl siding (but the front of my building and the front of the building across the street are indeed brick.)

What you are suffering from is known as multipath.

One way with the antenna that you have is to rotate it left and right and try to put the offending signals in the nulls of the antennas, while locking on another still in its polar pattern lobe.
I tried rotating the antenna and raising and lowering the antenna height, but the best signal strength I could get in the current location was between 75-85 (with frequent brief pixelation and intermittent signal loss).

I agree with EV about this being a multi-path issue. It seems you've gotten a "hot spot" in your apartment.
I attached a 50-foot coax cable to the antenna, walked everywhere inside the apartment, and found another "sweet spot" two rooms away. I was able to get a signal strength between 91-93 on WTTG FOX (real channel 36). For more than two hours, I did not experience any pixelation or signal loss while watching WTTG FOX.

What I don't understand is that WDCA MyNetworkTV (real channel 35)--which is the sister station to WTTG FOX, broadcasting from the same tower , and the same amount of power--only had a signal strength of 78-80. And every other channel had a signal strength between 65-75. And while watching these other channels, I experienced frequent pixelation and signal loss issues again.

When you tried the antenna outside, did you mount it vertically? Did you also try laying it flat?
I originally mounted the FV-HD30 antenna vertically outside. When I laid the antenna flat on the ground, it did, in fact, have *slightly* higher signal strengths, but this was only a slight increase, and it did not resolve the pixelation and signal loss issues.


I did not understand the following comments:

...you need to get an antenna with a higher F/B Ratio and a Tighter Beamwidth.

The Terk has a pretty tight UHF section and you can work the VHF Rabbit Ears into a tightening pattern or aim the nulls on VHF however its not very directional nor does it have a high F/B Ratio on VHF.

Try the Terk First.
Is there another antenna with a high F/B Ratio on both UHF and VHF that might work better than the Terk? If not, can you recommend a good place to buy the Terk that has an easy return policy?

Thanks again,
JB
 

EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#5
I am unaware of local Brick & Mortars that carry the Terk HDTVi.


You need to understand that you arent necessarily trying to maximize the Signal Meter (though often Bit Error Rates are integrated into the Meter).

You may find a position that offers less Signal Strength on the Meter, but avoids incessant pixelation and drop outs.

You are trying to find the magical voodoo position in which you have a much higher signal from one of two (or several, or a multitude) of signal paths coming into the antenna, and perhaps more importantly down playing or rejecting other signals. The signal is playing ping pong off the obstructions and buildings. These different pathways can be different for each real channel frequency as well.

So it's not necessarily easy what you are attempting to do, but its the only way forward, unless you get the building to install a Master Antenna on the roof.

I can give you some tips on positioning the Rabbit Ears, if you get the Terk HDTVi.

Hope that helps.
 
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EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#6
The nulls off of your current antenna occur at the ends of the points left and right 90 degrees from the face. But because it has a double loop (for UHF), this is muted somewhat.

The Terk HDTVi is a step in the right direction.
 

EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#10
I was thinking of your problem in the car today.

You said you were on the 3rd Floor and the building across the street is 4 floors. I think that you should try for the first knife edge refraction from the top edge of the building across the street.

Point the antenna right at it. See how that works.

Then, move the antenna at a steeper angle maybe 10 to 45 degrees above the ledge. With this you are trying to minimize the multipath from the ping ponging of the signal between your building and the one across the street, by moving it into a less sensitive area of the antenna polar pattern lobe, while still keeping the knife edge refraction from the roofline in the stronger area. Hopefully above the buildings will have less multipathic effects going on.

Position the VHF dipoles like this.

40" per side extended....in a 90 degree V pattern. Then angle them down to match the plane of the UHF log periodic triangular element(s).

Then point the whole thing at the roofline of the opposite building and above.

Try different locations as well. Even back out on the patio.

Report back.
 
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JBatch

DTVUSA Jr. Member
#11
Thanks…as soon as the Terk HDTVi arrives in the mail, I will give it a try.

Is there a good way to "mount" the HDTVi to adjust the angle?

Thanks,
JB
 

EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#12
Not really. And its kindof top heavy and clumbsy.

You will have to work something out with that, if you have success.

You can mount it to the ceiling or wall though. Ive seen that before.
 

JBatch

DTVUSA Jr. Member
#13
Could you please clarify this?

Position the VHF dipoles like this.

40" per side extended....in a 90 degree V pattern. Then angle them down to match the plane of the UHF log periodic triangular element(s).

Then point the whole thing at the roofline of the opposite building and above.

You can mount it to the ceiling or wall though. Ive seen that before.
If the dipoles match the plane of the UHF log periodic triangular element, and then I point the whole thing at the roofline of the opposite building, would the dipoles then be pointing down towards the floor? If so, how would I mount the antenna to the ceiling or wall where the UHF element is pointing up and the dipoles are pointing down. Would you happen to have any images that show the antenna mounted in such a position? Everything I have seen shows the antenna sitting level on a flat surface.

Thanks,
JB
 

EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#14
Dont know how to describe it to you.

When the unit is set on a table top..the triangle elements are pointing slightly upwards of perpendicular to the ground. The VHF telescoping elements should run parallel to this angle, with their tips foward the direction the triangle is pointing, and forming a 90 degree V, from the apex. That means that each one will be 45 degrees off axis of the direction the triangle is pointing.

Hope that helps.
 

EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#18
Just put them straight out at 15" per side perpendicular to the triangle and the body.

Any luck?

Focus on the UHF stations and see if the log periodic elements are getting rid of the incessant dropouts.

If so, then we can work on teh VHF telescoping dipoles.
 

EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#19
PS - If the Terk HDTVi works for you...

I thought of an easy angle mount for you. Clay, shaped in wedge. It is hefty and stable and you can form it around the base to hold it nicely.
 

JBatch

DTVUSA Jr. Member
#20
Not much luck with the UHF stations. I can get signal strengths in the 90s on UHF stations by aiming the antenna directly at the top of the building across the street, but I'm still experiencing experiencing pixelation and dropouts.
 

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