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Even though there are 16 matrix positions to program, there are some
shortcuts to make your job easier for normal ham band operation. Let's look
at the upper and lower band edges for the 220 MHz band:
Freq
N=
32
K
222.00
44,400
1
225.00
45,000
1
223.50
44,700
1
Notice that the values of the highest 6 positions are the same throughout the
band. We still must program in those six positions but we only need to
calculate for the remaining 10 (512 through 1).
Let's look again at the programming of 223.50 MHz Simplex, where N =
44,700. First, we see that the 32K, 8K, 2K and 1K positions are always
programmed with a diode and that the 16K and 4K positions never have a
diode installed. Let's put that fact to practical use:
1. We will always install diodes in the 32K, 8K, 2K and 1K
positions. This gives us an 'initial' N value of: 32,768 + 8,192 +
2,048 +1,024 = 44,032
2. This number can be used to START programming ANY
frequency within the Amateur 220 MHz Band. We need only add
additional diodes in the 512 through 1 positions for the various
channels within the band.
3. We determine these additional diodes by the same "Descending
Attempted Subtraction," that we used above for studying the
programming of 223.50 MHz Simplex, a process which you can
do in your head, with scratchpaper, or on the FX223
Programming Worksheet.
Let's do an example:
1. We're already familiar with the right answer for 223.50 simplex,
let's use it again. N = 223500 ÷ 5 = 44,700
2. Since we have already installed diodes in the 32K, 8K, 2K and
1K positions, our 'initial' N is 44,032. The N we need is 44,700.
3. We now figure the difference between the N needed and the
'initial' N: 44,700 - 44,032 = 668
4. Now, using the "Attempted Subtraction" technique, find the
remaining binary value to be programmed.
16
8K
4K
2K
K
0
1
0
1
0
1
0
1
0
1
0
1
1K
512
256
128
1
0
1
0
1
1
1
1
1
1
0
1
64
32
16
8
1
1
1
0
1
0
0
1
0
0
1
1
4
2
1
0
0
0
0
0
0
1
0
0
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