J.
Fixed Frequency Operation
The R-4A can be locked to a specific frequency by plugging the
appropriate crystal in the crystal lock socket, located on the left
side of the chassis, and positioning the XTAL/VFO switch to the
XTAL position.
When the switch is so positioned, the R-4A VFO and crystal oscillator
system will no longer control the frequency.
Crystals for this application should be of the parallel resonant
fundamental variety with HC-6/U holders. The frequency of the
crystal to be used in this socket should be equal to the desired
operating fre5645 KC or to l/2 of this value if it exceeds 15mc.
EXAMPLES:
Desired operating freq. 5645 KC = 12.800KC (crystal frequency)
or
Desired operating freq. 21,145KC + 5645KC = 26,790KC / 2 = 13,395KC
(crystal frequency)
A trimmer capacitor is provided directly below the crystal socket for
” pulling” the crystal slightly in order to get exactly on the desired
frequency.
The PRESELECTOR and BAND switch should be positioned as described
under “Accessory Frequency Coverage” for the desired frequency. If a
T4X is being used, placing the T4X TRANSCEIVE switch on SEP.CONT.
will result in the T4X being VFO controlled while the R-4A is xtal locked.
Placing this switch in the RCVR position will lock the T4X on the R-4A
lock frequency.
If the switch is placed on XMIT, the T4X controls both receive and
transmit frequencies. The lock crystal in the R-4A will then have no
effect.
Crystals for fixed frequency R-4A operation may be ordered direct from
the R. L. Drake Company.
When
ordering, be sure to specify that the
crystal you are ordering is for fixed frequency operation with the R-4A.
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