lpas7.art

一个很小和天线计算程序

subject: LPA series part 7

    BOOM SPACERS: These items are most important and they must cut
in such a fashion as to reflect the log-periodic nature of the
element design function. 

    In all the LPAs I have mentioned, each has two booms. These booms
must be separate both electrically and physically in the standard
LPA configuration.  This means that the spacers must be non-
conductive such as plexi-glass, hard rubber, wood, plastic, PVC, etc.

    Spacers can be attached to the booms in many ways such as the 
use of nylon screws and nuts, hose clamps, cable ties, etc.

    Currently I am using the PVC method which provides ease of 
parts and cost. NOTE: Be advised that at frequencies over 1 GHz,
PVC will become increasingly conductive.

    PVC can be cut to length and the log-periodic spacing can be
accomplished with ease.

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    MATCHING:  There is no required matching for the LPA. Coax
can be directly attached to the LPA. Normally the coax is run in the 
lower boom from the rear of the LPA or attached to the lower boom. The 
shield is attached to the lower boom and the inner conductor 
attached to the upper boom. This attachment is done at the front of 
the antenna and not the rear as most believe.



-WS