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New Member

Yagi Mounting Direction

Next week, I'm going to setup a wireless bridge using 1310's with Yagi's at both ends. My question is, which direction do I mount the Yagi's? In other words, should the antenna's be pointed at each other? How does the signal radiate from the antenna?

3 ACCEPTED SOLUTIONS

Accepted Solutions
Green

Re: Yagi Mounting Direction

IF you look at the yagi, one end will have fat elementts (longer elements), and the other end will have shorter elements.

On the end with the longer elements will be one element that forms a loop ... that's the radiating element.

The shorter elements are "directors" the longer elements are "reflectors"

You want to point the antennas such that the shorter elements face each other.

The radiation pattern is posted with the specs, just do a search on Cisco's main site (or from whoever manufacturered the antennas). Generally speaking, it'll be a long, narrow ellipsoid pattern extending in one direction, and a few "flower petals" around the other side. The flower petals ("inferior lobes")are the back side of the antenna.

Summary: point the directors (the shorter elements)at each other .... usually the mast will mount closer to the rear.

Also make sure you provie drip loops on the cable, strain relief the cable, and ensure there are no sharp bends, kinks, twists, or open cuts / breaks in the cable or jacketing.

Good Luck

Scott

Green

Re: Yagi Mounting Direction

For most Yagis @ 100 meters, cross polorization is probably not going to be an issue.

Good Luck

Scott

(and thanks for the ratings!)

Green

Re: Yagi Mounting Direction

I'm glad I was able to help.

It's always good for Warm & Fuzzy when the stuff works .....

Congrats!

Thanks again for the ratings, I appreciate it.

Scott

7 REPLIES
Green

Re: Yagi Mounting Direction

IF you look at the yagi, one end will have fat elementts (longer elements), and the other end will have shorter elements.

On the end with the longer elements will be one element that forms a loop ... that's the radiating element.

The shorter elements are "directors" the longer elements are "reflectors"

You want to point the antennas such that the shorter elements face each other.

The radiation pattern is posted with the specs, just do a search on Cisco's main site (or from whoever manufacturered the antennas). Generally speaking, it'll be a long, narrow ellipsoid pattern extending in one direction, and a few "flower petals" around the other side. The flower petals ("inferior lobes")are the back side of the antenna.

Summary: point the directors (the shorter elements)at each other .... usually the mast will mount closer to the rear.

Also make sure you provie drip loops on the cable, strain relief the cable, and ensure there are no sharp bends, kinks, twists, or open cuts / breaks in the cable or jacketing.

Good Luck

Scott

New Member

Re: Yagi Mounting Direction

Thanks Scott. With respect to mounting the Yagi’s, will there be a performance issue since the transmit Yagi will be mounted on a vertical pole and the receive Yagi will be mounted on a horizontal pole. Thanks for all your assistance.

Green

Re: Yagi Mounting Direction

Both side should have the elements oriented in the same plane (either both vertical, or both horizontal).

If you "cross polorize," it'll cost you no less than half your signal (~3db or more) as a general rule.

You can get crossmembers for vertical masts (which would be come vertical crossmenbers for horizontal booms) ... so perhaps you can adapt one side or the other.

Do whatever you can to keep both antennas in the same plane.

If you're absolutely stuck with what ya got, maybe shop around for amateur radio antennas used for satellite.

Satellite-specific Yagis are "Circular" polorization (right-hand or left-hand) they also have a little more loss over a give span compared to a horizontal ot vertically polorized antenna, but it's a pretty clean signal for terrestrial comms (signal quality is generally better than signal strength).

Good Luck

Scott

New Member

Re: Yagi Mounting Direction

The total bridge length is only 100 meters. Are you saying cross polorization is still a major issue? Thanks.

Green

Re: Yagi Mounting Direction

For most Yagis @ 100 meters, cross polorization is probably not going to be an issue.

Good Luck

Scott

(and thanks for the ratings!)

New Member

Re: Yagi Mounting Direction

Scott,

Last week, I successfully setup my first Wireless Bridge. I couldn't have done it without all your assistance. I appreciate your help greatly!! Jimmy

Green

Re: Yagi Mounting Direction

I'm glad I was able to help.

It's always good for Warm & Fuzzy when the stuff works .....

Congrats!

Thanks again for the ratings, I appreciate it.

Scott

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