900MHz yagi antenna location

danw

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danw
Join Date
Oct 2004
Location
midwest, USA
Posts
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The existing 900MHz yagi is mounted up tight against a steel walled building. The image shows a 'looking down' view. Low signal strength between the two points requires some remedial action. Radios are 1W FHSS ethernet radios.

My question is which is the best location to remount the antenna with a extended horizontal mast?

The location that places some of the steel wall behind the yagi or almost no steel behind the yagi?


2zpo1o8.jpg
 
I'm not 100% up to date on my antenna knowledge, I took a few classes back in college. But doesn't a Yagi-Uda antenna have most of its radiation pattern pointing in the same direction it is, and very little behind?
 
The metal behind a Yagi doesn't matter, as long as it isn't too close. It should be at least one wavelength away. For 900 MHz, that is about 33.3cm or or 13 inches. As Tharon stated Yagis are designed so the majority of the RF Energy goes off the end of the boom with the shortest Elements. I would recommend mounting it so that it is the easiest to handle, work on, and align.

Stu....
 
Spread spectrum or fixed frequency? Yes yagis have most out of the front, some from the sides and very little out of the back. What is the gain on the yagis and what cable are you using?
 
I'm weak on antenna knowledge so I can't add much more to this thread except to say that when I first read the thread title I read something entirely different than yagi antenna that I can't repeat here. :oops:

I have no idea where my dirty mind was.:confused:
 
>Spread spectrum or fixed frequency?

FHSS = Frequency Hopping Spread Spectrum

>What is the gain on the yagis and what cable are you using?

6.5 dB, LRM400 cable, standard N connectors

antenna specs (both ends)
2i4s2c.jpg
 
The yagis are pointed to each other in a point to point set up correct? Also the polarity needs to match or you will get a 20db drop right off the bat....
 
Is that drawing above the angle of the antenna? My wifi booster (dual band WiEx PCS CEL) with the "Yagi" upgrade is two flat panels with two coax cables and a signal combiner and they are aimed flat or as vertical square plates, I cannot imagine the antenna inside the opaque front panel being at an angle, but that is the extent of my knowlege of Yagi, and I still don't know what Alaric was chuckling about...
 

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