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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 remembered 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!
Although I used an N connector, other types of connector can be used if
preferred, it's just that a decent N socket costs about the same as a
decent SO239 so why not? 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. A hook can be made from a 20mm trunking saddle that has
been cut in half, with a slot filed into it where the top of the antenna (which has a rubber cap
on it) can sit. See photo bottom of page.
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