Scanner antenna - yagi vs tram

Status
Not open for further replies.

BITT211

Member
Joined
Aug 23, 2010
Messages
124
Location
ELMA , N.Y
Which is stronger reception scanner antenna ,

tram uhf 406-512 mhz [6.5 gain] omnidirectional type
or
yagi uhf 450-470 mhz [7.1 gain] 3 elements

have the tram mounted on 50' tower , my location is higher elevation

tram is working fine , hooked into a striedsburg powered coupler , heliax coax- 7/8"

looking for a little more distance , i am located on the rear part of my county so very little reception would be coming from rear of yagi . The yagi cover pattern would be fine for my coverage i need.

Would it be worth while in replacing tram with yagi ? Tower has tilt base , no problem there..

Thanks for any input
 

Attachments

Last edited:

popnokick

Member
Joined
Mar 21, 2004
Messages
1,904
Location
Northeast PA
Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 7_0_6 like Mac OS X) AppleWebKit/537.51.1 (KHTML, like Gecko) Version/7.0 Mobile/11B651 Safari/9537.53)

If you don't need to have much reception off the back of the beam (Yagi), then it will definitely outperform an omnidirectional antenna in the desired frontal lobe / coverage area. When properly installed of course.
 

WA0CBW

Member
Joined
Dec 8, 2011
Messages
1,247
Location
Shawnee Kansas (Kansas City)
Are both antennas using the same db's (dbd or dbi) ? If they are the same the difference is .6 db. It would be difficult to measure much less hear by ear a .6 db difference. The difference you might notice would be in that the beam would have a narrower beam width. You might have to turn the beam to hear different stations if they were beyond the beam width.
BB
 

jackj

Member
Joined
Jul 19, 2007
Messages
1,542
Location
NW Ohio
The difference in gain is negligible however there is a big difference in the antenna patterns. An antenna's gain is measured at the point in it's pattern where it has the MOST gain. A yagi's gain drops off to either side of that point. The beam width is measured at the points where the gain has dropped off by 3db from the peak and a drop of 3db is half of the power. On the other hand, an omnidirectional antenna has the same gain in all horizontal directions.

So an omni will out perform a yagi in most directions. The lone exception will be when the yagi is pointed directly at or very close to the station. There are very good reasons to use a yagi but they all have to do with taking advantage of a yagi's directional pattern, not its gain.
 
Status
Not open for further replies.
Top