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Hi All,

If an airplane passes close by...my reception cuts out/distorts for a split second.

Question: for my attic SBGH install, is there a way to prevent/minimize this ?

I read somewhere that you can use chicken wire ?


I searched the threads but cannot find info on this.:confused:
 

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My antennas are in the attic and I have noticed airplane interference too. When there is a plane in the sky nearby, I have a couple of drop out on my VHF 13 channel (WVNY-DT) and on weaker UHF stations.

It must be because the SNR ratio decreases when there is interference

you could add a noise filter, I am not sure if that can help or do more harm than good. I saw a noise filter for about 1$ the last time I went to Addison (a surplus store in Montreal)
 

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I also get airplane interference caused by the occassional giant C5 airplane going by, heh. On the set in analog, it kind of reminds you of a big boat going fast in a small river and kicking up a tremendous wake. Not too much can be done about that except to move. Building a DBGH with reflectors can help.
 

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The airplanes used to kill my signal, as I live right under their landing approach to Pearson. I installed a foil reflector covering the top of antenna, angled to the vertical at about 60. Works like a charm. A single plane won't affect me anymore, it's only around midnight when you can hear a chain of them following one another, some pixelation comes. The reflector is big enough to cover all the elements of antenna (SBGH).
 

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This very topic came up in the past with someone living near Toronto's Pearson Airport and I suggested putting up some foil or mesh vertically above the antenna, which worked for that person. Of course each situation requires testing. ;)
 

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Discussion Starter #7
name777 ,I'm near your location. And will try your method.

Thanks everyone for the replies !
 

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Since I was on the lookout for it, I noticed this morning when a low flying helicopter flew by it caused pixelation for about 2 seconds on my digital channel 17.2 (real channel 54). Not a big deal, heh.
 

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Aircraft can cause interuption of signals? That certainly explains my situation! I live 3 miles from the Fort Rucker gate, here in Ozark, AL. This is the home of US Army Aviation. Helicopters fly around the clock here. One of their landing pads is only 1 mile from my location.

I constantly have pixelation with signals from 50% to 80%.
 

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The only really reliable way to prevent this is to get line of site with the transmitter. That means raising the receiving antenna. (Paying the station to raise their transmitter might also work. ;)) Improving the forward gain by making the radiation pattern more focused vertically will also work. That can be obtained by stacking elements vertically (as is done with some popular UHF designs.) The more elements that are stacked, the better the resistance to "airplane flutter" will be. Parabolic dish designs (once a popular UHF antenna configuration) will probably also be more resistant to this problem.
 

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For something like that you could look at hardware cloth too (usually .5" x .5" metal mesh) because it is flexible and can be easily tweaked in real time as you adjust it. It doesn't always work for everyone but it can make a big difference with low-flying aircraft flutter and other such things.

Testing a Faraday Cage solution like this on DTV is tricky without a signal analyzer but I've always found that setting it up on a weak analogue station is easy as you see the effects immidiately! ;)
 

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I have noticed that I have breakups/interference quite often for US channels, .......... then it is just frozen (or, it's showing "no signal" or "signal cannot be decoded") for one or more seconds. One thing that I noticed is that when I had the breakouts/interference, in most cases, I heard airplane.

So I was wondering if airplane is the cause of the breakouts / interference

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What you're experiencing is a phenomenon known as "Airplane Flutter"

Since you live near the Airport the jets are coming in low over your home and they are reflecting the signal causing a multipath


Airplane flutter is a very important problem. It
causes the receiving antenna to receive both direct
signal by the Tx (Transmitter antenna) and reflected
signal scattered by the airplane with phase delay. The
sum of two signals results in fading, sometime collapse
and distortion of picture on TV screen.

http://2003.iccas.org/Full_Paper/airp_ICCAS2003_5(19).pdf

This document on the subject deals with the phenomenon on VHF and analog TV signals… however Digital TV on UHF is affected too in the exact same way.

A well known solution to this problem is to stack 2 identical antennas vertically connected together in phase.

Where I live in Mississauga I get jets flying in right overhead doing their approach to YYZ. When I was using a Wingard 9032 I use to experience the Airplane flutter problem on WUTV digital 14. But for the last 2 years I switched from using the Wingard 9032 to a more sophisticated antenna the DAT-75. The DAT-75 uses 3 vertically stacked beams at different vectors. I just wanted to point this out… since this antenna seems to have solved the Airplane flutter problem I was experiencing.

Wingard 9032


DAT-75
 

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Stampeder/HDTV101,

I tried restoring the mast and I lost some channels. So, I put it angled just a little bit and they are back. I still notice the interference, and again, I heard airplane when it happened. I guess it is airplane flutter as HDTV101 said. I guess the simplest way to fix this would be to put the shielding (rather than to stack identical antennas). I'll try this first and see what happens.

Stampeder, I looked at the link you gave me. Is there more detailed explanation as to how big the shielding is, how to attach it to the antenna etc.?

HDTV101, rather than stacking 2 antennas, would it be helpful if I replace my CM4221HD with CM4228HD?

Thanks.
 
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