MFJ MFJ-9219, Инструкция по эксплуатации

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MFJ-9219 QRP Tuner, Wattmeter, & Dummy Load Instruction & Technical Manual
STAGE 2
Step 1 Engage the tuner (Switch 8).
Step 2 Set the TRANSMITTER control to 5.
Step 3 Set the ANTENNA control to 0.
Step 4 Apply just enough RF power to obtain a noticeable deflection on the multipurpose meter.
Step 5 Adjust the INDUCTANCE control to find the lowest SWR.
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Step 6 Slowly adjust the TRANSMITTER control until the lowest SWR is obtained, then repeat
with the ANTENNA control. These controls interact, so it will be necessary to switch back
and forth between adjusting controls until a minumum is found.
Step 7 After the lowest SWR is obtained, use the INDUCTANCE switch to reduce the inductance
by one switch position. Adjust the TRANSMITTER and ANTENNA controls for the lowest
SWR. Continue this process until the lowest SWR cannot be repeated, then use the
INDUCTOR switch to increase the inductance by one switch position. Tune for lowest SWR.
Step 8 Set the SWR/Wattmeter to bypass.
4.1 THERMAL WARNING
The resistor network in the MFJ-9218 is made up of eight 100Ω 2W surface-mount resistors. Six
are used in SWR mode and all eight in Dummy Load and Power mode. Due to the small size of
the devices the temperature increase is substantial. Above 5W limit the transmit time in SWR,
Wattmeter, and Dummy Load mode to less than the time listed in Figure 7 and allow the resistors
to cool for 2 to 5 minutes between transmissions. It is recommended to keep the power below
100W in BYPASS mode.
Figure 7: Safe transmitting times as a function of RF power
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Never transmit while adjusting the INDUCTANCE switch.
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