Magnetic Loop with RoomCap on 20m
upd 30th November 2006 /
time it was my desire to compare the RoomCap antenna
with a good
magnetic Loop antenna.
On November 30th 2006 this test took place.
The test was assisted by Edy, HB9EBG.
Comparing antenna = Magnetic Loop, 85cm diameter
of loop, 35 mm diameter of tube,
tube, silver plated, with Annecke butterfly capacitor
remote tuning, in vertical position.
= RoomCap for 20m, 5cm diameter, length of radiator =
Both antennas were placed at the same height (150 cm
above ground) in a free field,
using the same 100 W transceiver, and adjusted to VSWR
In total, 13 comparing QSOs were conducted in the time
between 13.30h to 16.00h.
In each QSO the antenna was quickly changed many times
and the remote station
was asked to indicate the average signal strength difference between
the two antennas.
In all contacts the RoomCap was reported clearly as the
stronger antenna, where the
smallest reported difference
was 1 S point and the largest difference was 5 S points.
Here follows the list of the reporting stations with the
indicated difference in S points.
LY3ZM + 3
UA3AIU + 1,5
YO3AJN + 2
EA8BRW + 2
LY2SP + 4
UR0EA + 2
UT8NF + 1
YO6KSU + 2
This corresponds to an average difference of 2.11 S
An S point is defined as 6 dB, resulting in about 12 dB
(It is clear, that the receivers many times do not
this definition, but in the average this may be close
= 12 dB = 16 x Power for Roomcap!
Therefore, see the comparison with vertical and
Below you see the test installation. On the left the
and on the right the magnetic loop antenna.
Felix Meyer HB9ABX + Edy HB9EBG