120 20191-001
Paragon-III
Technical Manual
29
5.2.3.4
Low-Frequency Balance Adjustment
Note:
•
PGM800Win version 3.00 or later must be used. Electronic potentiometer (256 step) is
used to allow channel adjustment of two-point modulation (Low freq. balance).
1.
Apply the following settings to the IFR:
–
Receiver mode and Oscilloscope display (Source Demod out connector, DC coupled).
–
IFR RX frequency to match the radio transmit frequency
–
IF Filter set to 30KHz
–
Zoom the Deviation window: select 10kHz Range and DC coupling.
2.
Select the active or, the lowest (in the case of multi-channel base) frequency channel (via dip
switch, refer to Figure 17)
3.
Transmit a square wave by using CDip (using a second serial port).
4.
Press EPOTs button. Adjust IC220 via PGM800Win “reference modulation” to obtain the best
square wave, no damping, no overshoot. (You can use either the mouse or up and down arrow
keys). Record the deviation read.
5.
For single-channel unit, proceed to step 8.
6.
For multi-channel unit, select the highest frequency channel. Transmit a square wave via CDip.
Record deviation again.
7.
The difference in deviation between the two channels should be less than ±300Hz. If not, re-
adjust IC220 to "average" the square wave shape on both channels until the spec is met.
8.
To confirm the adjustment, select the active, or the lowest frequency channel. Compare the devia-
tion produced between 1000 Hz sine wave test tone and Random data test pattern
The difference between the test tone and the test pattern should be less than 1.9 kHz for
xRC16FSK modulation set
For multi-channel unit, repeat this step on the highest frequency channel.
9.
Select the active channel. Transmit a TX ON (Modulated) adjustment tone via CDip. Make sure
that deviation level read on the IFR correspond to bit rate in use (see Table 4 at step 6). Re-adjust
deviation as necessary.
5.2.3.5
Exciter Power Output
1.
Apply the following settings to the IFR:
-
Receiver mode, Output T/R
-
IFR RX frequency to match the main radio TX frequency
-
IF Filter set to 30KHz
-
Select auto range in the
Power reading
window
-
Connect the coaxial cable from the IFR T/R to the Exciter output connector
2.
Key the Exciter by pressing the module PTT button. The output power at the coaxial cable end
connecting to the power amplifier should be:
-
T881 = 5W +0/-300mW (RV502, Figure 21)
