Specifications

Technical Manual Installation and Operation

RELM/

BK RADIO

♦ Adjust the TCXO to within +/- 20Hz.

♦ If the RX centre frequency cannot be adjusted the TCXO may be faulty.

♦ Distortion should be less than 3%.

♦ If the distortion is high then FL3A, FL3B or FL4 may be faulty.

♦ If the sensitivity is still poor then return the Module to your Service Centre.

6.4 Exciter Module

6.4.1 VCO Locking

♦ Check the reference frequency of X2 (13 MHz) is the same as the TX Reference

Freq. in the ‘Hardware Settings’ in the built in menu system.

♦ Connect a DVM to the ‘TX VCO’ TP on the Microcontroller PCB and PTT,

check the Tx locking voltage is between 2 – 14 V.

♦ If the Tx locking voltage is out of spec then slowly adjust L48 on the TX VCO

and check for a change in the locking voltage.

♦ If there is a change in locking voltage, then realign the VCO voltage to 14V at

Upper frequency of the VCO frequency band.

♦ If there is no change in the TX VCO locking voltage then check the VCO supply

voltage TP4 is approx. 7-8V and with a CRO check the TCXO is oscillating on

pin 12 of IC14.

♦ If all the above tests didn’t pass then the VCO or IC14 may be faulty. Return the

to your nearest Customer Service Centre.

6.4.2 RF Power

♦ Using in-built menu system increase the ‘Transmit Power’ control to maximum

and check that the output power is greater than +24 dBm.

♦ To insure power control is at max Short C208 together, (located under SKB)

♦ If the Exciter power is low, check for the +8 V supply voltage at the outputs of

TR27 and TR16.

♦ Lift one side of C216 which leads to R128 and solder a flying lead to that end of

the capacitor, check the output power of the VCO is between ≥ +7dBm.

♦ Use a RF probe to check for gain through TR27 and TR16.

♦ If all the above tests didn’t pass, then return to your nearest Customer Service

Centre.

6.5 Power Amplifier

♦ First do a visual check of all the components on the PA looking for any damaged

components.

♦ Connect the input of the PA to signal generator with the RF output switched off.

♦ With PTT off measure the +13.8V supply at the Source of the driver and output

FET . If out of spec then check voltage at CN2-2, no volts then check supply

cable.