Aiming a yagi antenna

[towhee_falconer]

When I am setting up a yagi antenna - Do I need to consider the elevation of the tower relative to my antenna? If the tower I am listening to is on a hill, should I angle my antenna up at it, or should i just angle the antenna toward the broadcast tower?

 

[prcguy]

If you have to look upwards more than about 10deg to see the hill I would first hand hold the Yagi and point it not only side to side but up and down to find the rough peak. Then when you permanently mount the antenna you will know what your up against. The peak will be very broad and you have to go way out either side and up/down to find where the signal degrades equally on either side then estimate the center of two equally degraded points. I actually have a patent on peaking a certain satellite dish using a form of this method.

 

[jwt873]

Can you see the hill? If so, there's no need for a Yagi. (Unless you're isolating a simulcast site). If you can pick up the signal with a vertical antenna, then there's no need to angle the Yagi.

If the site is distant and you're using the Yagi for its gain, then because of the distance, the transmitting antenna will be appearing not too far above the horizon. (The further away you go from a site,, the closer to the horizon it will appear).. In this case, the elevation angle doesn't really matter.

For example, there's a UHF repeater I use. It's on top of a 250 foot building. But it's 30 miles away. I can pick it up with a vertical antenna at 30 feet, or a fourteen foot long 21 element Yagi at 25 feet. In this case there's no advantage to changing the elevation of the Yagi. Heck, there's no advantage to even using the Yagi.

For satellite work, then it's -very- important that you adjust the elevation since they can be many degrees above the horizon.