COMPARISON: Magnetic Loop with RoomCap on 20m
upd 30th November 2006
/ 7.2.2015                      


Since long 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,
                                    copper tube, silver plated, with Annecke butterfly capacitor
                                    with remote tuning, in vertical position.
Test antenna            = RoomCap for 20m, 5cm diameter, length of radiator = 150cm,
                                    without top capacity.

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 1:1.

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.

YO5PDW   +1
LY3ZM      + 3
RU6AH      +1
UA3AIU    + 1,5
YO3AJN   + 2
EA8BRW + 2
LY2SP      + 4
UR0EA    + 2
YO4AAC +1
UT8NF     + 1
YO6KSU  + 2
UR5HDE   +5
SV0XBA   +2

This corresponds to an average difference of 2.11 S points.
An S point is defined as 6 dB, resulting in about 12 dB advantage.
(It is clear, that the receivers many times do not follow exactly
this definition, but in the average this may be close enough.)
Result:
  = 12 dB = 16 x Power for Roomcap!

Therefore, see the comparison with vertical and horizontal wire
antennas here

Below you see the test installation. On the left the blue RoomCap
and on the right the magnetic loop antenna.

comparison on 20m

Felix Meyer HB9ABX
+ Edy  HB9EBG

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