FX 146
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through 1K programming positions. If an auxiliary split is needed or if you are
not licensed to transmit in a band portion, do not install diodes in SIMP,
+RPT or -RPT positions.
Using Computer BASIC as a Diode Matrix Programming Aid
The purpose of the following BASIC program is to be as CLEAR AND
GENERIC as possible with no concern for programming efficiency or
sophistication. Those who enjoy and understand programming in Basic can
dress it up to suit themselves. Or, they can write a program that satisfies
their own standards. A major purpose of the deliberate simplicity is that the
routine should run on virtually any computer using any version of Basic. If
you follow the program flow, you'll see that it carries out in order the very
same steps you would follow by hand in converting decimal to binary using
the FX Programming Worksheet. You can use this same program for
calculating nonstandard Transmitter Offsets.
Program Notes:
1. Install diodes ONLY in rows where "1" is indicated.
2. If you prefer, "0's" can also be generated through the use of appropriate
IF . . . THEN . . . ELSE lines.
3. The "!" after 32768 is generated automatically by the computer, whether
you type it in or not.
4. Be VERY accurate in typing "<" and ">" or "=>" because they are critical
to correct placement of 1's.
5. The CLEAR instruction after screen printing is important; if it is omitted,
AA, BB, CC, etc., will not be reset for checking the next frequency.
6. Innovative computer programs to enhance enjoyment of the FX
transceivers are encouraged; send them to your favorite ham or computer
magazine, newsletter or BBS.
7. LPRINT or equivalent Basic statements can be used to produce
hard-copy printouts of frequency information you need.
8. IMPORTANT: Before soldering ANY diodes in your FX-transceiver
programming matrix per this program, CHECK AND VERIFY that your
program is giving CORRECT results! COMPARE it to the samples in this
book.
NOTICE:
Although this program has been tested on many Microsoft BASIC
releases, including GW Basic, it is printed here solely as a convenience
and is not integral to the Ramsey FX-146 operation. If you have trouble
running the program, please get help from a local computer friend and
not from the Ramsey factory - we're radio guys, not computer hackers!
FX-146
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Easy enough! Whenever you want a transmit offset that is higher than the
receiver or repeater output frequency, simply find the the N number for the
offset and program it on the offset matrix.
Here's one more example. Let's say we want a + 1 MHz offset.
1 MHz = 1000 KHz. 1000 ÷ 5 = 200 = N
Converting to binary: (Obviously 200 is less than all values from 8K through
256, meaning that we need no diodes in those positions.)
Can we subtract 128 from 200? YES (Therefore diode at 128)
200 - 128 = 72
Can we subtract 64 from 72? YES (Therefore diode at 64)
72 - 64 = 8
Can we subtract 32 from 8? NO (Therefore NO diode at 32)
Can we subt ract 16 from 8? NO (Therefore NO diode at 16)
Can we subtract 8 from 8? YES (Therefore diode at 8)
This +1 MHz TX offset is set up easily by diodes at 128, 64 and 8!
Programming of Minus offsets is covered in the Reference section of your
manual.
ADDITIONAL CIRCUIT NOTES:
The 19 100K resistors at the frequency programming matrix and the 14
100K resistors at the offset matrix are called "pull down resistors" and are
required to ensure positive logic switching action of U6.
Transistor Q15 and its associated switching diodes ensure that the desired
offset is switched in during transmit, that offset programming does not
interfere when simplex is desired and that the offsets do not interfere with
receiver operation . . . and that receiver programming (21.4 MHz lower) does
not interfere with transmit operation. Obviously, these simple parts must be
installed correctly, or major PLL problems would result.
Stage H: PROGRAMMING MATRIX ASSEMBLY
There are two diode matrix programming areas on your PC board. The
obviously larger area is for frequency channel programming. The second
space is for offset programming added in by U7-U10.
Correct assembly of the following section permits Q15 to switch off all three
transmit offset programming lines while receiving, allowing only the RECV
programming to be in effect. Be certain to orient the diodes correctly.
Install the following resistors:
?
H1: R68, 1K (brown-black-red).