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Old 4-May-2012, 2:48 AM   #14
Dave Loudin
Senior Member
 
Join Date: Jan 2010
Location: King George, VA
Posts: 659
@mike_sl, thank you for dialing down the discourse. I failed to respond to you in a way to keep the temperature down, and I apologize. I was trying to offer that we try not to focus too much on one particular manufacturer when several choices are valid. For example, the Winegard HD769x and AntennaCraft HBU lines offer similar performance. Choosing which one gets down to personal preference and costs. As @GUM said, we use the noise margin predictions, the range of channels, and the spread of azimuth required.

One factor you are probably not fully aware of: as antenna gain increases, the azimuth range the antenna will be sensitive to decreases. The hazard of going for high-gain antennas where they are not needed is you may now have to use a rotator to get all the channels you want.

Another factor to consider about the predictions generated here or anywhere else: there is an implied reliability of 90%. This means what you see for noise margin will be met or exceeded 90% of the time. With short paths, the variability is typically small, so the statistics are tight. For the long paths, especially the long 2-edge and tropo ones, the variability is much greater, so the statistics are far looser. For those stations (generally the double digit negative noise margins), the signal you will see 1% of the time will be something you can receive. This could appear as coming in a couple hours per day or only on cool nights or...

You've got some excellent choices. Good luck.
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