POWER - SWR METER
The meter circuit allows measurement of the forward and reverse power in two ranges, 0 - 200 W
and 0 - 2 KW. Measuring SWR is covered in step 8 above.
CAUTIONS
1. In the normal operation of the Model 229 matching unit very high RF voltages and currents
can occur at some points in the circuit. Be very careful if the tuner is ever used while the
cover is removed.
2. While all the comonents are rated to easily handle continuous operation at maximum power,
certain loads will produce currents which exceed the "hot switching" capabilities of the
ceramic wafer switches. Therefore, never change the position of either switch with high rf
power applied. However, up to 100 W rf may be hot switched on S1 during the initial tune up
procedure. Failure to observe this warning may result in permanent damage to the contacts
of the wafer switches.
3. Always be sure that a dummy load or antenna is properly connected when power is applied.
Voltages in excess of ratings can occur if no load is connected.
SEVERAL OPERATING HINTS
If it is noticed that placing your hand on the top of the tuner causes a shift in SWR, it is an
indication of excessive "rf in the shack." Improve the ground system or change the length of the
feedline slightly. This is especially noticeable when using wire-fed antennas.
When using BALANCED LINE, if the SWR rises during a long transmission, it is an indication that a
significant portion of the transmitter power is being lost in the balun. This will be the case when the
antenna impedance is greater than 500 ohms. Changing the length of the antenna and/or feedline
will usually cure this problem.
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