lpas8.art

一个很小和天线计算程序

SUBJECT: Log Periodic Arrays, part 8. Conclusion

    ANTENNA MOUNTING:

    There are several ways to mount the LPA to a tower or a rotator.
All this depends on what you are looking for in an LPA.  The LPA can 
be mounted at the back-end or in the middle.  It can be mounted to a 
rotator or to the side of a tower.  It can be stacked, arm mounted,
or all by itself. It can pretty much be treated like a yagi.

    KINKS:  When mounting the LPA (not to be confused with the LPDA) 
the antenna *should* be mounted to a nonconductive support. The 
antenna is balanced and no part of the LPA is unbalanced.  This is 
not the case in the LPDA where the boom is independent of the 
elements. Both booms in the LPA are part of the antenna and are an 
active part of the antenna.  They are the feed elements of the 
antenna unlike the LPDA. 

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         *** DO NOT MAKE A METAL PLATE TO MOUNT THE LPA ***

    All this will do is short the two booms together and effectively
destroy the antenna as an LPA!

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    Mounting the LPA via the end mount way can be accomplish in two
ways; first a fixed mount directed to a particular station or area
of interest. Also the end mount can be put on a rotator provided that
the amateur balance the weight load of the LPA with a counter weight
or another antenna 180 degree out from the LPA.

    You can use U-bolts provided they do not touch or even come close
to touching but use a non-conductive plate like wood or plexiglass. PVC
mounting works well and frequencies below 2 GHz.


-WS