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Old 18-Jan-2010, 10:08 PM   #7
Join Date: Dec 2009
Posts: 632
Originally Posted by Witty1 View Post
I am puzzled as to why I cannot get by local ABC (KOMO) station (once I can get this one, I am good to go).
That is strange considering how strong that signal is.

You may want to try pointing the antenna in very different directions to see if the station ever comes it. Perhaps you are getting a signal reflection off of another object (e.g. building/hill/trees) in the environment. Extra signal "echoes" or "ghosts" can interfere with the correct decoding of the digital channel. This "multi-path" effect is a form of self-interference that can make life difficult for your receiver.

The C2 antenna has a pretty wide antenna beam width, so it might be gathering signal from the "main" and "echo" paths simultaneously. If you try turning the antenna to other directions, you might be able to get the antenna to "turn a blind eye" to some of those extra unwanted signal paths. If turning the antenna off-axis reveals a different sweet spot for receiving this channel, then your problem may very will be multipath.

Multipath can affect each channel differently because the wavelength of each channel is different. The various distances between objects can cause the signal to constructively or destructively interfere with itself at different places based on the frequency. This is why you might see this behavior on one channel, but not another, even if they are broadcasting from the same tower.

If you problem is indeed related to multipath, then one of the ways to combat multipath is to use a more directional antenna. The C2 antenna has a pretty wide beam width. An antenna with a narrower beam width will be more "selective", and will tend to filter out extra unwanted signal paths more effectively. Or, you might just be able to find a sweet spot for your current antenna that fixes KOMO without messing things up for all the other channels. This part will take some trial-and-error.

when I moved the antenna from one location to another, I had it sitting on the ground and it was able to receive KOMO… I thought elevation was my friend, but not quite certain with the results I am seeing!
This may be related to multipath. Some locations might avoid an unwanted signal echo that makes this channel fail.

You may also find that some receivers are more robust against multipath than others. A TV's built-in tuner vs. a converter box vs. a PC tuner card may yield different results from the same signal feed. More recent ATSC chipsets have made significant improvements in their ability to handle multipath signals.
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