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Flowerpot Antenna for Airband
As I've already featured a couple of Flowerpot antennas elsewhere on my
website I won't go over all the details again, but for reference those
pages can be found by clicking here and here.
This page is really just to document the different dimensions of the
airband version compared to the 2 metre/dual band versions, which apart
from the radiating elements is essentially the same.
I started by following the measurments suggested by the online flowerpot antenna calculator
but these needed 'tweaking' slightly making the final length about 3cm
longer. A near perfect VSWR was achieved exactly at the centre of the
airband, but although this appears to have a fairly sharp dip, it must
be remenbered that the airband is 19MHz wide so it would be asking a
lot for a single band antenna to have a flat response over such a wide
bandwidth. It is a receive only antenna after all so nothing is going
to blow up!
The easiest way to mount an 'open' coax antenna like this is up in the
loft space where it can be hung from a rafter. The image on the right
shows an 'N' socket but other types of connector can be used if
preferred. Good quality coax is recommended from the antenna to
the radio. |
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