by N4ON a low power portable ham radio antenna.
I call this a plastic antenna because of its low weight, a plastic backbone support, and
little to no metal except in the wire, the connectors, the capacitor, and the knob screw.
The antenna was tested both inside the house and outside.
Test were conducted using a RigExpert AA30 and a RigExpert AA170 analyzer.
Using two analyzers helps eliminate any discrepancy while verifying the two analyzers.
The antenna was mounted on a music stand with no modifications except for
removing the music shelf holder from off from the top of the tripod.
The music stand can be easily adjusted for the height of the antenna from the ground.
The music stand neck fits the antenna base perfectly.
The three wide legs on the music stand provide outstanding antenna support.
Be sure to have the necessary BNC adaptors and cables and a low power SWR meter inline at all times.
Also be sure that all the loops are on the same side of the plastic tube support.
The easy instructions are displayed on the antenna. I begin my test by turning the knob all the way
clockwise to the end stop, then I measured the lowest frequency. On 7 Mhz, 40 meters, the SWR was
always 2.0 minimum. Moving the antenna outside and inside, walking around the antenna, etc. the antenna
remained stable, on frequency with a constant SWR 2.0, which I consider a plus for stability.
I do wish that the SWR could be 1.5 or better like all the higher bands and frequencies I tested.
Adjusting is sensitive because of the narrow bandwidth. Draw your own conclusions from
my test results below. Actual test using a radio will follow later.
I have only had this antenna for one day.
DAY 1
The lowest frequency of my antenna that I tested.
The highest frequency of my antenna tested.
The total bandwidth at the edge of the 40 meter band was 12 Khz. (+/- 6 Khz.) @SWR 3.0
SWR below 2.0 was very narrow, about +/- 2 Khz. All readings improve at higher frequencies.
As I increased the analyzer bandwidth, the analyzer was less and less able to detect the
antenna resonance.
I selected a frequency just below the edge of 40 meters so the narrow
bandwidth could be viewed just to the right on the graph instead on
right on the center frequency line of the graph blocking the view.
