MFJ-8100
World Band Receiver
9
RECEIVER CONTROLS AND CONNECTIONS
Most of the controls are self explanatory. However, it is
very important to understand the correct use of the
Regeneration Control and the two internal trimmer adjustments
of the receiver.
BANDSWITCH (SW1)
This quality rotary switch selects any one of the 5 tuning
ranges from A to E indicated on the tuning scale.
TUNING (C1)
The Tuning knob controls an air-variable capacitor (C1) which
also has a built-in 6:1 vernier reduction drive to which the
dial pointer is attached. This reduction permits very smooth
tuning. The frequency markings on the dial scale must be
understood to be approximate due to the 10% tolerance ratings
of the fixed inductors (L1 through L5).
PUSH SWITCH (SW2) AND L.E.D. INDICATOR (CR1)
While the purpose of the on-off switch and LED is obvious,
remember to turn your receiver OFF when not in use. A
weakened battery degrades receiver performance.
REGENERATION (R1)
Because understanding and controlling regeneration is at the
heart of your receiver's performance, we've provided a
separate section on its use. In brief, it controls receiver
sensitivity and adjusts between AM broadcasts and CW-SSB.
VOLUME (R2)
This potentiometer performs the normal function of any volume
control. Of interest to the technically-minded, it controls
the output of the LM386 audio IC, rather than the input,
which enhances the stability of the regenerative detector.
RF GAIN (R9)
This trimmer potentiometer is adjustable with a small
screwdriver. Maximum gain is clockwise when viewing the rear
panel. A good normal setting is 3/4 of its full rotation.
If you are using a marginal antenna (5 to 10 feet of wire
indoors), keep R9 at its maximum setting. If you are using a
very good antenna (a long, high outdoor wire or ham antenna),
keep R9 at about 2/3 or so of its range. If your listening
interests require frequent RF gain adjustments, install an
external 10K control in series with your antenna.