Vertical radiator:
Take a piece of wire of about 8ft3", strip it apart, solder it together so
the total length is16ft 4". Now solder a clip on both ends. You can use
electrical tape of heat shrink tube to sturdy the center joint and the clip
joints and keep the wire from breaking off. Needless to say, you can also
use a single piece of 16ft
Through the top ring of the crappie pole, tie the piece of nylon wire
such that it makes a loop. You will clip/hang hand the vertical radiator
onto this.
Ground radials:
Take 4 pieces of 17 ft speaker wire. Solder a clip to both conductors on one
side. Strengthen join with tape of shrink tube. From the other, strip wire
apart. You now have 4 pairs of 17ft ground radials.
Putting it together:
Put a 2 ft piece of 3/4" PVC pipe through the center of an old tripod.
Or use a stick put into the ground, or saw a point onto the same piece of
PVC and stick this into the ground. You will mount the fishing pole over
this after it's been erected (and you have unscrewed the bottom cap.)
Clip on vertical radiator to the loop at the top of the pole. Extend the
pole. Put it over the mount.
Clip the BNC female chassis adapter to the vertical radiator. See photo
1.
Put the coax into the BNC connector.
Clip all 4 radial pairs clips onto the connector; spread out the 8
radials as evenly as possible in a circle around the antenna. (You can
obviously make more radials, this will probably improve performance
somewhat. Going beyond 16 radials, i.e.. 8 pairs, will probably not help
much)
After this, I use some velcro tape to hold this concoction to the pole,
but this is optional.
Now you basically have a 1/4 vertical with ground plane for 20m. (see
photos 2&3) I have successfully used this antenna in my back yard, and
around a few campgrounds (photos 4&5.)
Several times I have gotten an SWR of around 1.5:1 and needed no tuner to
operate. Running low power, I have made lots of interesting contacts around
the country and the world with this! Because the angle of radiation angle is
low, this is a good DX antenna!
I have tuned this antenna on 30m and 15m and made satisfactory contacts.
For permanent use on 30m you can lengthen the ground radials. You can also
hang 17m, 15m, 12m and 10m vertical radiators on the same pole by soldering
then onto the same clip on one side of the 20m radiator. (Use 12.9ft,
11.1ft, 9.3ft, and 8.3ft respectively) Then tape them to the longer
wire where they end (since these are shorter). This should allow for a
relatively decent multi-band ground plane antenna, while keeping
construction and cost low. Due to interaction of the various vertical
pieces, you will either have to tune the lengths of these somewhat, or use a
tuner to satisfy your transmitters input impedance.
The whole antenna, apart from coax and pole, easily fits into a zip lock
bag for transportation! |