802.11 2.4Ghz Low-Power 5dBi Vertical Collinear Antenna
The length of the feedline is approximately 9.15cm.
Note that the first measurement from the end of the decoupling tube is a 1/2 wavelength to the beginning of the first coil.
The next critical measurement is from the middle of the coil to the beginning of the first brass tube element, which is 1/4
wavelength. The cycle then repeats again for the remaining elements, where a 1/2 wavelength exists between the beginning of
the next brass tube element to the beginning of the next coil.
Construction
Decoupler Assembly:
The decoupler assembly is a simple process. First, set the SMA connector upright with the legs facing up. Then apply some
solder to the soldering iron and then apply soldering iron with solder on tip to the center conductor of the SMA connector.
Apply a little more solder to the now very hot center conductor and then pull the soldering tip up and away from the center pin.
Take care in ensuring you didn't create a solder bridge between the center conductor and the Grounding pins. Next put the
feedline into a vise, and apply heat to the top of the feedline tube. With a free hand, pickup the SMA connector and put it onto
the very hot feedline tube. You may need to apply a little heat to the solder bulb on the center conductor to get the solder to flow
from the cold connector down into the feedline. When the connector rests purpendicular to the top of the feedline, remove heat
and wait to cool. When completed, it should look like Figure 5.
Figure 5: The image on the left shows the solder applied to the center conductor now resting on the feed prior to feedline
heating. The center image shows the feedline in vise, after heating the tube and allowing the connector to rest flat on the top of
the feedline tube. The image on the right shows the completed feedline soldered to SMA center conductor.
(C) Aerialix 2002 (5 of 13)
