some pages concerning NO RADIALS verticals. These are typically antennas such as
the Cushcraft, R5, R7, R7000 and other similar designs. They use a matching box near
the base of the antenna and 4 or 6 little spokes which act as a counterpoise. I have
owned an R5 (got damaged in the 1998 ice storm) AND an R7. I bought a complete R7
black box at a ham radio flea market and used it to build a 20 meter monoband vertical
with no radials.
the Cushcraft, R5, R7, R7000 and other similar designs. They use a matching box near
the base of the antenna and 4 or 6 little spokes which act as a counterpoise. I have
owned an R5 (got damaged in the 1998 ice storm) AND an R7. I bought a complete R7
black box at a ham radio flea market and used it to build a 20 meter monoband vertical
with no radials.
Often during Field Day..I set up a temporary antenna and work Field Day in my back yard from a picnic table. This Field Day (2005) I built a
prototype 20 meter monoband vertical. I used my R7 black box (base matching unit). I mounted it on the back of my truck (visible in this
picture). I ran the coax over to the picnic table and worked some stations during Field Day. The bottom section of the vertical is a fiberglass
pole (green). It is actually a tree pruning clipper to clip brances off small trees. Being Fiberglass..it is easy to interface with both
mechanically and electrically. The base section with the U bolts is from an old vertical antenna. I lashed it all together for Field Day and it
worked fine.
prototype 20 meter monoband vertical. I used my R7 black box (base matching unit). I mounted it on the back of my truck (visible in this
picture). I ran the coax over to the picnic table and worked some stations during Field Day. The bottom section of the vertical is a fiberglass
pole (green). It is actually a tree pruning clipper to clip brances off small trees. Being Fiberglass..it is easy to interface with both
mechanically and electrically. The base section with the U bolts is from an old vertical antenna. I lashed it all together for Field Day and it
worked fine.
I used copper pipe strapping from the hardware store to wind a helical winding on the fiberglass pole. The aluminum tubing is
above this.
above this.
It was a pretty tall vertical antenna. As I recall it was about 26 to 28 ft long. The R7 is similar to a 1/2 wave vertical. I used some inductance in this
antenna in order to make it a manageable length and in order to make it adjustable.
antenna in order to make it a manageable length and in order to make it adjustable.
The tweaker coil is a stack of yellow (nr 6) torroids that I put inside a large glue stick. I merely took a short length of aluminum ground wire
and wound a coil around the glue stick and it interfaced between the main aluminum tube upper section of the vertical and the lower
fiberglass/helical section. The glue stick tweaker coil allowed me to tweak the vertical for resonant frequency. I did this rather than the cut
and prune technique. The vertical was quite large in size and I did not want to take it up and down for adjustments.
and wound a coil around the glue stick and it interfaced between the main aluminum tube upper section of the vertical and the lower
fiberglass/helical section. The glue stick tweaker coil allowed me to tweak the vertical for resonant frequency. I did this rather than the cut
and prune technique. The vertical was quite large in size and I did not want to take it up and down for adjustments.
click here for more info/pictures of this antenna experiment