User's Manual

DRAFT 1

76 Installation TB9300 Installation and Operation Manual

5. Change the RF input signal to the new receive frequency at

–80dBm. Check that the RSSI reading is –80dBm ±1dB. If it is, the

receiver front end does not require tuning. If it is not, go to the next

step.

6. Using the Johanson tuning tool

, adjust the correct helical filter for

the new frequency (as shown in Figure 5.3) to obtain a peak RSSI

reading. This reading should be within 1dB of the reading at the

previous frequency.

Adjust the center resonator of the filter first, followed by the two

outer resonators (in any order). Each resonator should require

approximately the same amount of adjustment when tuning.

A change in frequency of 5MHz requires approximately one turn of the

tuning slug. If tuning to a lower frequency, adjust the slug in (clock-

wise); for a higher frequency, adjust the slug out (counterclockwise).

7. Change the RF input signal and the reciter’s receive frequency to

0.5MHz above and below the required frequency and check that the

RSSI reading does not drop by more than 0.5dB from the reading at

the required frequency.

8. Recalibrate the RSSI at the new frequency (Calibrate > Reciter >

RSSI).

If you wish to confirm the accuracy of the tuning procedure, carry out a

sensitivity measurement at the new frequency.

K-Band Reciter The K-band reciter does not require tuning.

1. Included in the TBA0ST2 tool kit. Also available separately as part num-

ber 937-00013-00.