Ramsey Electronics FZ-146 Specifications download pdf (Page 132)

FX 146 • 132

However, DO NOT INSTALL L9, R32 or L10 UNTIL AFTER ALIGNMENT

HAS BEEN COMPLETED. Whether you test now or later depends on

how anxious you are to see (and hear) the results of all your hard work.

If you are still awaiting your ham license, you can test the FM

modulation of buffer stage Q10 and also enjoy your receiver fully. Be

aware, however, that the buffer stage, even with no antenna connected

to it, has a transmitting range of about 100 feet, even through walls and

obstacles.

TRANSCEIVER PLL ALIGNMENT (May also be done before Step TX35)

Our goal in this test is to verify speech amplifier operation (U4), actual FM

modulation of a low-level RF signal (Q10), and correct operation of the PLL

Frequency Synthesizer in Transmit mode. If an antenna is connected for this

test, it will affect receiver operation only. The "antenna" for the 10 milliwatt

output consists of of the lead lengths and circuit-board traces associated

with C76 and C82.

TEST PROCEDURE:

1. Make sure work area is cleaned up and that the PC board is checked for

wire scraps lodged between connections, etc.

2. Set transceiver frequency to 146.52 MHz Simplex.

3. Obtain or make a non-metallic alignment blade capable of turning the

slug in L7 and also turning trimmer C81.

4. Connect speaker, microphone, antenna and 12-15 volts DC. (Antenna

will serve receive function only.)

5. Connect a digital voltmeter (DVM) of known accuracy to TP1 (red + lead

to the test point, and black lead to ground). Set the meter to the lowest

DC range that will handle up to 7 or 8 volts. A digital voltmeter is used

for this procedure because it has the required high input impedance.

6. With the transceiver power turned on, press the microphone button and

adjust L7 for a reading of 1.6 VDC at TP1.

7. A precision adjustment of C81 requires either a frequency counter

connected to TP2 or a digitally accurate VHF receiver tuned to 146.52

MHz. With the microphone keyed (button pressed), C81 is adjusted for

exactly 146.52 MHz on your Ramsey frequency counter or a zero-beat

146.52 MHz signal on a digitally accurate monitoring receiver. If you

cannot tune C81 low enough, install C80, 39 pf (this places more

capacity across C81). An adequate initial adjustment of C81 can be

made by listening to your signal on any VHF FM receiver and carefully

adjusting C81 for the clearest-sounding signal. Or: adjust C81 for the

best reception of a transmitted signal of known accuracy. This might be

all that you'll ever need to do, but it is recommended that you make the

precise adjustment when possible.

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Ramsey Electronics FZ-146 Specifications Page 132