where:
RECEIVER PROGRAMMING
Programming
of the receiver diodes is similar to the transmitter. The only diHerence in the procedure is the
applied formula. For receiver programming
the following formula is used:
N
=
[(RX - 21.4)
X
.5 - (frx X 2)
i
x
400
N
diode programming
position
RX
=
receive frequency (MHz)
frx
=
ranging crystal frequency (per chart 4.2 above)
Example: Desired receive frequency
=
157.750 MHz
N
[(RX - 21.4)
x
.5 - (frx X 2) X 400
[(157.750
- 21.4) X .5 - (29.75 X 2)
i
X 400
[(136.35)
X .5 - (59.50») X 400
[68.175
- 59.50)
X 400
8.675
X
400
3470
8y referring to the above charts, the programming
diodes needed would be:
3
(83, A3)
4
(C2)
7
(C1, 81, A1)
O
Installation of diodes 83, A3, C2, C1, 81, and A1, wili program the reeeive frequency of 157.750 MHz.
RANGING CRYSTAL SWITCHING
An additional diode location exists in each section of the matrix board. These locations (next to the AO
position of each section) are for the purpose of crystal switching
into operationRX1
or RX2. Location A
corresponds
to channel 1; 8 corresponds
to ehannel 2, ete ... If all locations are left empty, RX1 will be
switched into the eircuitry. Whenever a channel assignment requires the ranging of erystal RX2, a diode
should be installed into the proper loeation/ehannel
assignment.
Example:
Location:
A (CH 1)
8 (CH 2)
C (CH 3)
D (CH 4)
E (CH 5)
F (CH 6)
Note: Locations G through L are unused.
Diode Installed?:
NO
NO
YES
YES
NO
YES
Crystal
Used:
RX1
RX1
RX2
RX2
RX1
RX2
OIOOE INSTALLATION
The programming
diodes should be earefully formed and installed with a low temperature
soldering
iron.
As many diodes must be housed in a smail location, care must be taken to assure that all diodes are
installed neatly and with equal spacing.
7
