Palstar ZM-30, Руководство пользователя

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19
51 ohms
Feedline with unknown
characteristic impedance
Short
inner lead
to shield
Tune for minimum SWR.
Freq where SWR is min is ½-wavelength
Figure 4: Determining Length of Halfwave Stub
Use VFO mode to dial in the desired operating frequency.
Then disconnect ZM-30, connect Xcvr and operate!
Figure 5: Adjust Antenna Tuners
P
To
antenna
Antenna Tuner
Adjust freq “F” for lowest SWR
Figure 6: Capacitor or Inductor Measurement
51
ohms
L
C
C =
25330
F 2 * L
C in pF
L in uH
F in MHz
Sweep frequency to find minimum SWR point at “Fc”.
Then find freqs where SWR=2:1 below and above
Figure 7: Antenna Bandwidth
To
antenna Fc
SWR
2:1
1.1
BW
L =
25330
F 2 * C
Figure 8: Determining Feedline Characteristic Impedance
Set pot to max (1K-ohm).
Adjust pot slightly lower.
Tune ZM-30 from 7-21 MHz.
Note variations in R and X.
Relatively constant?
no
yes
Pot setting is cable’s
characteristic impedance
1K
pot
Freq
51 ohms
Sweep ZM-30 to find minimum SWR at some frequency “F”.
Figure 9: Determining Feedline Velocity Factor
(Open)
VF =
10
F
L =
5904 * VF
F
L is length in inches
VF is Velocity Factor
F in MHz