FIGURE 5-2. Bandwidth Adjustment Test Setup.

TM 11-5820-917-13

h. Adjust R49 DC and R37 GAIN controls

until step e above is satisfied. R49

will move both traces up and down together

on the CRT; R37 will spread or com-

press the spacing between the traces for a

given audio frequency. Note that

these adjustments interact slightly so care

must be taken and adjustments repeated

until proper alignment is achieved.

NOTE

If adjustment procedure time takes longer than one sweep of the RCS-4B

(280 seconds), allow second sweep to start under PROGRAM mode and then

repeat steps a and b above to verify sounder sync.

5-21. FREQUENCY STANDARD ADJUSTMENT. Over long periods of time, the

temperature controlled quartz crystal in the frequency standard will show effects

of precession (frequency change due to crystal aging) . When the rate of pre-

cession in the receiver and transmitters is not equal, the Chirpsounder record

displays may drift up or down on the receiver CRT display. Normally, a record

can be recentered on the CRT by means of the receiver SLIP control. If adjust-

ment of the SLIP control is required more than once in eight hours, there is need

to adjust the frequency standard. If all transmitter displays drift on the CRT in

the same direction, it is necessary to adjust the receiver frequency standard.

However, if at least one transmitter does not drift, or drifts in an opposite

direction, then adjustment of the TCS-4B transmitter frequency standard is re-

quired. The operator of the drifting transmitter should be notified and informed

as to the rate and direction of drift as observed on the receiver CRT. (For

example, Chirpsounder record drifts up 20% of CRT height per 24 hours.)