ANTENTOP-
01- 2004, # 005
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Something
about ATU
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L-
Matching Unit
Fig. 14 shows L- MU. This one is a simplified
version of Pi- MU. ATU, keeping L- MU often is used for operation
with simple tube and transistor transceivers and for matching
simple multi- range antennas, which do not contain large reactive
component.
Parts
for the ATU
The data of spools for the MU exhibited on Fig.
2 are shown in Tab. 1,
for the MU exhibited on Fig. 3
are shown in Tab. 2.
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Table 1 Data for MU shown
on Fig. 2
Frequency band,
MHz
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1,9
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3,5-3,8
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7
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10
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18
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14
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21
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24
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27-30
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Diameter of
spool, mm
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50
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30
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25
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25
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25
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25
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25
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25
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25
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Length of
winding, mm
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50
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30
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40
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40
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40
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40
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30
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30
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30
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Number of
turns
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100
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30
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20
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15
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10
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11,5
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8,5
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7,5
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6,5
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Table 2 Data
for MU shown on
Fig. 3
Frequency
band, MHz
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1,9
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3,5-3,8
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7
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10
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14
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18
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21
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24
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27-30
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Diameter of
spool, mm
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50
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40
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25
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25
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25
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25
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25
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25
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25
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Length of
winding, mm
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60
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40
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40
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50
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40
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40
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40
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40
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35
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Number of
turns, n
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130
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35
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28
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20
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15
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11,5
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11
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9,5
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8,5
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Tab. 3 Data for
digital inductor shown in Fig. 9
Inductance,
μH
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8
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4
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2
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1
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0,5
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0,25
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0,12
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Diameter of
spool, mm
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30
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20
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20
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20
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25
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10
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10
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Length of
winding, mm
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30
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20
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25
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20
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20
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10
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10
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Number of
turns, mm
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20
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18
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12
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8,5
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5
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6
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4
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It is possible to use for T- MU any
variometer, which is possible to get. Variometer has to have maximum
inductance not less than 30-μH
and minimum close to zero. If the maximum of the inductance of the
variometer is less, for expansion of frequency range of the ATU
to include in serial with the variometer a fixed inductor. If the
minimum inductance of the variometer does not reach zero, it is
essentially cut off the upper range of operation of the ATU. |
The design data for spools for digital inductor shown on Fig. 9 are shown in Tab.
3. Significant RF-currents flow through parts of MU - capacitors, inductors,
and switches. So all of the parts should be qualitative.
73!
I.G.
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http://www.antentop.org/
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