CONNECTING A 75 OHM COAXIAL ANTENNA LEAD
VHF-TV ANTENNA CONNECTION
Fig. 19—Connections for a 75 ohm antenna.
An unbalanced 75 ohm antenna can be connected
to the MR-65 with coaxial cable. Connect the center con-
ductor to the right FM ANT screw and the shield to the
grounding screw next to the antenna screw as in Fig. 19.
The Mclntosh designed balun matches the 75 ohm input
to the tuner for optimum performance.
Fig. 20-Connections for sharing a VHF-TV antenna.
The MODE SELECTOR switch disconnects the VHF-
TV antenna from the TV set and connects it to the MR-65.
When the MR-65 is turned off the switch re-connects the
antenna to the TV set.
Connect the VHF-TV antenna to the FM ANT termi-
nals and connect a 300 ohm flat ribbon wire from the
terminals marked TO TV SET to the antenna terminals
on the TV set. (See Fig. 20).
OPERATING THE MR-65
Fig. 21-Front Panel Controls.
MONOPH0NIC FM PROGRAM
Turning the MODE SELECTOR to FM turns the MR-65
power on. Turn the VOLUME CONTROL to its mid point,
the AUTO. FREQ. CONTROL all the way to the right, and
the MUTING switch to the IN position. After a warm up
of about 30 seconds turn the tuning knob to find the
station of your choice.
While tuning the MR-65 you may notice the meters
indicating a station yet no program is heard from the
speakers. The muting circuit in the tuner is rejecting the
station because there is objectionable noise with the
weak signal from the station. Turn the MUTING switch to
the OUT position and the station will be heard. Most
programs that can be tuned in this manner are of poor
quality due to interfering noise.
The AFC action is electrically delayed to permit tuning
without AFC and without turning switches to disable the
AFC. After tuning is complete the AFC automatically locks
on the station. The MR-65 may be accurately tuned with-
out having to "split hairs." The very best performance
with a minimum of experience or effort results from the
action of the new AFC circuit. For critical tuning, merely
tune until a station is heard from the speaker, and then
the AFC, after a few seconds delay, automatically centers
the station on the channel.
If two stations are next to each other the AFC action
may tend to capture and hold the stronger station. By
turning the AFC knob to the left the amount of AFC is
reduced and the weaker station of the two can be tuned
and held. The quality of the audio program is unaffected
by the amount of AFC used.
STEREOPHONIC-INTERNAL MULTIPLEX (MPX)
After the MPX adapter has been installed in the
prepared space on the chassis, MPX stereo broadcast
programs can be received. Turn the MODE SELECTOR
to MPX STEREO and use the rest of the controls as in
"Monophonic FM Program" above. The volume control
is not operating in this position.
When the MR-65 is tuned to any station broadcasting
stereo the MPX adapter will separate the "left" and
"right" channels for stereo reproduction by the loud-
speakers.
STEREOPHONIC-EXTERNAL MULTIPLEX (MPX)
With an external multiplex adapter plugged in the
MPX OUT jack all controls are set identically to the
"Monophonic FM" settings.
STEREOPHONIC-FM-FM or FM-AM
With a separate tuner plugged in the STEREO IN-
LEFT jacks and the MODE SELECTOR in the EXT STEREO
position FM-FM or FM-AM stereo broadcast can be tuned.
The MR-65 supplies the right channel program and the
separate tuner supplies the left channel program.
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