QRP (Plastic) Antenna Test and Review
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.
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
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.
I quickly connected a 4 Watt CW QRP rig to the AlexLoop antenna.
All SWR reading were somewhat better than the two analyzers indicated.
I was using a Diamond SX-200 SWR meter.
Using an ICON IC-7000 running 12% power ie. 10 watts, the SWR was 1.5 or better on all bands.
Because band conditions vary greatly, QSO's and stations worked with signal reports are not performed
for this review. This antenna is a "keeper" because it is my first truly portable inside antenna that receivers
extremely well, easy to set up and take down, plus is so compact and light weight. I only wish it could
handle more power. Expensive for what you get, but worth every penny for its performance as a low
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