Dobrynin I., Moscow
# 1, p.22
Twin Magnetic Antenna has some advantage compare
to a usual magnetic antenna.
advantages are that the twin magnetic antenna, compare to usual
magnetic antenna, has higher Selectivity and higher Effective
Height. Twin Magnetic Antenna was tested in a pocket transistor
radio. The antenna was able to receive radio stations from the
distance up to 800- km. Figure 1 shows the antenna.
Figure 1 Twin Magnetic Antenna
Twin Magnetic Antenna consists of from two
usual magnetic antennas switched into bridge.
height of the antenna would be higher in
to with a single magnetic antenna.
Thereof the L1 and L2 are connected to a bridge
the inductance of the each inductor should be higher (for the
same working band) compare to inductor for a single magnetic antenna.
CQ-QRP # 42
Receiver DEGEN- 1103 (in the USA/Canada it is sold as Kaito
1103) has sensitivity at MW near 100-micro-volt/m and at LW near 1- milli-
volt/m. The sensitivity may be increased at least in 20- times
if the receiver would be placed inside a loop shown on Figure
2. Sensitivity of the receiver depends on distance between axis
of the loop and wires of the loop.
Loop with sizes 300x400- mm made of from wooden
stick with sizes 50 x 10- mm. Loop contains 10- turns of the copper
wire in 0.8- mm diameter (20- AWG). At the MW range the Loop is
tuned by a variable capacitor 3x (12…500-
pF). At the LW range an additional capacitor is switched to bridge
to the variable capacitor. The additional capacitor may have capacity
1500- 2000- pF.
Figure 2 Loop for DEGEN 1103