ANTENTOP-
02- 2004, # 006
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Old
Receiving Magnetic Loop Antennas
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a
suitcase and using a loop magnet antenna is described in the reference
[5]. Fig. 6 shows
the circuit and design of the loop antenna. It was used two magnetic
loop antennas, M1 and M2. Lengthening coils are switched in serial
with each loop antenna (L1 to M1 and L2 to M2), necessary for exact tuning
of the loops to frequencies range needed. Both, M1 and M2 are used
at LW. When the loop works at MW, M2 is shortened, and only M1 does
receiving.
Magnetic antennas M1 and
M2 have sizes 315x 245 millimeters, M1 contains 14 turns of Litz
wire 30x0,06, M2 contains 50 turns of
Litz wire 15x0,05. As a last resort, instead of a Litz it is possible
to use a copper insulated wire in diameter of 0,15
millimeters.
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Figure 7
SW magnetic loop antenna
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Lengthening
inductor L1 contains 50 turns, lengthening inductor L2 contains
125 turns, the wire is Litz 15x0,05. These
inductors are reeled on a form in diameter of 8 millimeters. The
width of winding is 7 millimeters for both inductors.
Short
Wave Magnetic Loop Antenna
Magnetic loop
antennas were used not only for LW and MW,
also the antennas were used for SW. For example, in the reference [5] it was described a SW magnetic loop antenna
which was used for 19-75 meters. The loop antenna was simultaneously
the input circuit of the receiver. A variable capacitor 12x500-pF
does tuning to a resonance of the loop. Fig.
7 shows design of the antenna.
The
antenna is made of a copper strip 6x3 (width in 6 millimeters, thickness
in 3 millimeters). Such strip is used for winding welding transformers.
The loop antenna contains 2 turns, the distance between the turns
is 10 millimeters, inductance of the magnetic loop is 3,1-μH.
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References:
1.
Schegolev E. I. Radionavigation. Moscow, GITTL,
1946.
2.. Sheinman A. Z. A collective-
farm broadcasting center. Moscow, Zhurgazob'edinenie, 1938.
3. Atabekov G. I. Linear electric circuits. Moscow,
Energy, 1978.
4. Amateur
Battery Radio Receivers. Moscow, MRB, Gosenergoizdat, 1950.
5. Troickiy L. V. Circuits of Amateur Receivers. Moscow, MRB, Gosenergoizdat,
1956.
73!
I.G.

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