shipping or handling abuse, should still be in perfect
order; however, before flying it is best to check. Tuning
and sensitivity is checked by operating receiver with
antenna-less transmitter and noting the maximum dis-
tance operation can be obtained. To do this, point the
sub-antenna of your Mark II Mule transmitter, main
antenna removed, at the stretched out endofthe receiver
antenna and key tone signal. If you get good operation
out to a distance of 15" all is in order to fly. If not,
accomplish the following check. Install tuning meter and
note at the 15" distarice if current is rising to 40 ma.
If so, then relay adjustment or cleanliness is reason for
non-operation. If' small or no rise is noted, receiver
tuning is probably at fault. To retune the receiver, use
the following procedure.
-The tuning tool should be insulated and fabricated to fit
slots of both the antenna, coil and IF cans. Do not use
metal screwdriver or metal tipped tools. Again, operate
receiver with antenna-less transmitter, bringing it
close enough to receiver antenna to get a small reading.
Start at the mixer IF can (yellow slug) and slowly adjusr
slug for highest reading on meter. As the slug is peaked
and current rises to the maximum level of about 48 ma,
back transmitter away to drop the current so an exact
peak can be obtained. Do not try to peak any adjustment
with receiver current at saturation level, back trans-
mitter away to weaken input signal so peak can be
obtained. After the mixer has been peaked, go the first
IF (white slug) and repeat the above. In sequence, back
away transmitter and weaken signal each time adjustment
brings current level to saturation. In same manner,
peak the second IF (yellow slug) and last, with receiver
lid on, peak slug of antenna coil. Presence of receiver
lid will not affect IF tuning, on or off, however, it does
affect the antenna coil. You will note while tuning that
adjustments to the mixer and first IF are somewhat
critical but tends to broaden out at the second IF and
antenna coil. This is normal. When tuning is finished
you should get at least a 40 ma reading at the minimum
15" distance. The average will be about 24". This
completes the tuning adjustment.
Do not attempt tuning by the distance check method. It
cannot be done. You may try a ground distance check
for personal satisfaction, if desired. If properly tuned
as described ahove with minimum of 15" operation,
ground range (receiver held head height) will be in
excess of one-half mile in open country.
