Shively Labs 6822, Instruction Manual Installation, Operation, & Maintenance, Page: 60 / 78

Startup
52
Impedance trimming.
If your antenna is equipped with the optional Shively fine-matching trans-
former, adjust the transformer ( Figure 40 ) as follows:
a. Loosen the hose clamps on the tuning stubs enough to allow the stubs to
move.
b. Grasp one of the tuning stubs and slide it in or out about 1/4 inch or 6
millimeters. It will move stiffly because of O-ring friction.
Figure 40. Impedance-matching
transformer
c. Read the VSWR. If the reading went down, move the control rod again in the
same direction. If the VSWR went up, move the same rod in the opposite
direction. Repeat until no further improvement is seen.
d. Adjust the second and third tuning stubs in the same manner.
NOTE
If you get "lost," return all three tuning stubs to the factory setting (all
the way out) and start over.
e. Return to the first tuning stub, and so forth, until you have the lowest
possible VSWR or return power reading. This is the optimal transformer
setting at this frequency.
f. VSWR for each frequency at this point should be below 1.2 : 1. If it is not,
call Shively Labs to help identify the problem.
g. When you have set the transformer, use a sharp point to scribe the shaft of
each control rod where it leaves the flange collar. Record the settings of the
control rods and file this information with this manual for future reference.
h. Tighten the hose clamps. If the clamps are left loose, vibration may change
the adjustments.