Ramsey Electronics FX Series Manual page 120

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 223.50 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 223.50
MHz. With the microphone keyed (button pressed), C81 is adjusted for
exactly 223.50 MHz on your Ramsey frequency counter or a zero-beat
223.50 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.
8. While speaking in the microphone, adjust modulation level (R46) for the
best sounding speech. "Best" is not necessarily the maximum: see the
following note. NOTE: R46 adjusts the FM deviation of the transmitted
frequency. Deviation is carrier frequency swing in step with voice
modulation. If you "over-deviate," your signal will not be stronger. Instead,
the speech will become distorted and "splash" over to adjacent channels.
Deviation is a very important adjustment: "best sounding speech" will
usually result in the proper 5KHz deviation used on VHF FM.