PreppComm DMX-40 Manual de usuario
Making Communications Fun Again!
QUICK START GUIDE
By Eric C Anderson, PreppComm
Version 3.0, August 2021
Copyright © 2020 PreppComm. All rights reserved.!
Copyright © 2020 PreppComm. All rights reserved.
BEFORE YOU BEGIN:
Decision Time
QRP Transceiver
or
Base Station Decoder/Encoder?
Before you start into the Quick Start Guide, let’s decide how you are going to use it?
There are two sections to the guide:
1. QRP Transceiver: Getting started using your DMX-40 as a QRP (low power)
Transceiver on 40 meters. This is referred to as the "Transceiver Mode." In this
use, you only need the DMX-40, the keyboard, a set of headphones or powered
speaker, and an antenna (or dummy load if you are learning how to use it). Go to
Section I below.!
2. External Transceiver Decoder/Encoder: This is for when you want to
connect your DMX-40 to your base station transceiver to use as a CW decoder/
encoder. This is referred to as the "External Mode or Companion Mode." This
mode enables use of the internal computers for decoding and encoding, and uses
the receiver and transmitter inside your base station transceiver. This allows the
decoder and encoder to operate on any band your base station operate on, and at a
higher power level, set by your base station. Go to Section IV for setup.
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Copyright © 2020 PreppComm. All rights reserved.
I. Section I: QRP Mode Setup
1. Set up the DMX-40 as shown in Figure 1 below. Do not apply too much force
when plugging in the keyboard - make sure you have the USB plug correctly
oriented and aligned. Do not apply any downward pressure.
FIGURE 1: STATION SETUP AS STAND-ALONE STATION
2. Turn on the transceiver using the RED power switch.
WARNING: NEVER OPERATE THE TRANSMITTER WITHOUT A LOAD ON THE
ANTENNA CONNECTOR. DOING SO VOIDS YOUR WARRANTY FOR ANY
DAMAGE CAUSED BY AN UNLOADED TRANSMITTER.
If you plan to use a key to transmit, this will be covered at the end of this section.
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Note: You can turn off the internal transceiver by pressing the frequency button until it
says "External." This is what we refer to as External Mode, or Companion Mode, and is
discussed in detail in Section II. Pressing it again restores transceiver function
The Splash Screen will display for approximately 3 seconds, as shown in Figure 2
below.
FIGURE 2: SPLASH SCREEN
The Main Screen then is displayed, as shown in Figure 3 below.
FIGURE 3: MAIN SCREEN
3. Press the Menu Button, and the Main Menu screen will display, as shown in
Figure 4 on the following page.
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FIGURE 4: MAIN MENU
4. Press the LOCAL STATION SETUP button at the top of the menu. The Call Letters
entry screen will display, as shown in Figure 5 below:
FIGURE 5: CALL LETTERS ENTRY SCREEN
5. Enter your call letters assigned to you by the FCC. Use backspace or delete to
edit if you make a mistake. Note: you do not have to hold down the caps key - all caps
is automatic. Press the NEXT button to continue.
6. Using the NEXT buttons, proceed through a series of screens and enter the
required information
a) Name, or in ham radio lingo, your Handle, such as JOHN
b) Location, or QTH in ham lingo, such as CHICAGO, IL
c) Rig Type (PREPPCOMM DMX-40)
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Copyright © 2020 PreppComm. All rights reserved.
c) Antenna Type. If you don’t have an antenna yet, put NO ANTENNA.
d) License Level. Select your FCC license level
The License Level Entry screen is shown in Figure 6 below.
FIGURE 6: LICENSE LEVEL ENTRY SCREEN
7. Press the FINISH button on the License Level Screen
You will be returned to the Main Screen. You have now completed initial setup of your
DMX-40 transceiver. Before we proceed, it is important to understand how the
Frequency Button works (see Figure 3).
The Frequency Button
The DMX-40 can be thought of as two separate parts: the computer part, and the
transceiver part. The computer portion is always active when power is on. When you
see a frequency value in the Frequency Button, the transceiver section is also enabled,
and the receiver or transmitter is active, depending on receive/transmit state. .
However, when you see the word "External" instead, the internal transceiver, both
receive and transmitter, are inactive.
External Mode aka Companion Mode is useful for experimenting with the operation of
the DMX-40 without causing interference on the band, or when using the DMX-40 with
an external transceiver, allowing the computer section to control that external
transceiver by sending Morse code to it via the KEY IN/OUT jack, and listening to its
receiver via the AUDIO IN jack. Switching between Normal and External modes is a
simple touch on the Frequency Button.!
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Copyright © 2020 PreppComm. All rights reserved.
II. QRP Mode: Using the Transmitter
Also note: When in External Mode, the receiver is also disconnected.
In this section we are going to familiarize you with using the four different call and
answer functions built into the DMX-40.
1. Press CALL. On the status line, you will see the question SET CALL WPM = ?
Asking you to specify how fast to transmit, as there is no history to base that on at
this first transmission, and the CALL button will turn RED."
2. Press SPACE BAR to set the default 20 WPM. You can change the default."
3. Watch as the DMX-40 transmits the general calling sequence."
4. Press CALL to end the sequence. Sequence continues until complete, and ends
with a Kappended. The CALL button will turn AMBER during the ending of the
sequence. K means "Anyone Come Back." Note that the general call will run until
you end it. Typically you will run it for 30 - 90 seconds when on the air."
5. Press NO CCS button and enter the call letters of a station you would like to call.
Press SPACE or FINISH to complete and return to the Main Screen."
6. Note the CCS Button now has the new call sign you just entered loaded. NOTE:
the decoder can also fill the CCS button from a received station."
7. Press CALL to start the directed call sequence. Note it will automatically use 20
WPM from recent history."
8. Watch as the DMX-40 calls the specified station. Press CALL again to end the
sequence. Note that KN is appended at the end, which means "only the station I
am calling, come back.""
9. Press the ANS Button twice, quickly. The first press will result in a RED button,
the second press will result in an AMBER button. Ignore the Type-Ahead Buffer
Pop-Up."
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IMPORTANT: Use a DUMMY LOAD or the External Mode while practicing CALL
and ANSWER functions. Press the Frequency Button until it says External. This
prevents accidental interference on the 40 meter band.
Copyright © 2020 PreppComm. All rights reserved.
10. Watch as the DMX-40 transmits the answer-validate sequence. This is a short
station ID used when you are responding to another station’s CQ (general call) to
attempt to establish a 2-way communication. If they answer you, then a 2-way has
been established, and communication can begin. Answer Validate is not required if
you make a call and someone answers you."
11. Press ANS once. The button turns RED, and a Type-Ahead Buffer pops up.
12. Type a tilde (~) character, then press ANS again. The button turns AMBER."
13. Watch as the DMX-40 sends the initial station ID, followed by the INFO
microprogram, which is generated when you type in a tilde character. The Type-
Ahead Buffer goes away as soon as the tilde is read out. The final station ID back
to the other station completes the transmission, with a KN."
14. Think up a short message, such as "HI, BOB. HOW ARE YOU TODAY?""
15. Press ANS and IMMEDIATELY type your message. You should be able to type at
least part of the message during the station ID, and then your message will begin to
transmit.
16. Press ANS again to specify your typing is complete. Your message will appear in
the Type-Ahead Buffer, until the station ID has completed, and then it will be read
out one character at a time."
17. You now have a basic idea of how to use the four main transmit functions:
1. General Call
2. Directed Call
3. Answer-Validate
4. Answer
These built-in microprograms (CALL, ANSWER, and INFO) can be customized and
controlled from function keys using RPL (Rig Programming Language) in our
microprogramming system. There are 12 user-defined microprograms. Watch our
YouTube video on microprogramming to get a "starter set" to play with.
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Copyright © 2020 PreppComm. All rights reserved.
III. QRP Mode: Using the Receiver
1. Background
Obviously, the first thing you need to do to tune in a station is... remove the dummy load
(if you used one) and connect to a real antenna. A good antenna is a critical aspect of
any radio station. Since you are running QRP (Low Power), a good antenna is truly a
MUST.
One one level, tuning in a station is fairly simple: you scan up or down the band looking
for a signal, and stop and adjust around the signal so that it is decoding correctly. On
the other hand, it can be quite daunting.
Why can it be daunting? There are several reasons that you need to be aware of. First
and foremost is the "band condition." The band can be "open" or "closed." It depends
primarily on the sunspot cycle, the current sunspot activity, and time of day. If you hear
nothing on the band, the band is probably closed, or, as they say DEAD. Try later.
However, a dead band does not mean you can’t connect with someone nearby (local).
If you have a scheduled time and frequency to meet, even if the band is dead, i.e., long
distance communications is out, local can still work quite well, depending on your
antenna. Typically, the 40 meter band opens in early to mid afternoon, and is open at
various distances - ever growing farther and farther away - until very early morning. By
that I mean oh-dark-thirty. It’s all about the ionosphere and its height above the earth. It
rises at night, and thus your "skip" distance increases.
2. Receiver Incremental Tuning
You may have noticed after transmitting that the Frequency Button changes to show
RIT +0. RIT stands for Receiver Incremental Tuning. This decouples the receiver
frequency from the transmitter frequency. The transmitter frequency remains constant,
but you can make minor adjustments to the receiver frequency, as needed. Specifically,
when another station comes back to you the first time, their frequency may be slightly
off, and you may need to adjust the receiver frequency to remain set for optimal
decoder operation. More on that below.
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NOTE: For this section, you will need a real antenna, and the Frequency button
should show a frequency value, not External. Press the button to switch to
Frequency Mode, which turns on the transceiver inside the DMX-40.
Copyright © 2020 PreppComm. All rights reserved.
3. Receive Mode Keyboard Commands
Figure 7 below is a diagram showing the receiver keyboard commands. You can tell
that you are in Receive Mode because both the CALL or ANS Button are BLUE. Press
MENU / HELP / RECEIVE for a summary of these commands. The commands are on
two separate screens, which you can access via the NEXT and PREVIOUS buttons.
The EXIT button will return you to the Main Screen.
Note that on the Help Screen, there is also help for TRANSMIT and MICROPROGRAM
commands, as well.
FIGURE 7: RECEIVE MODE KEYBOARD COMMANDS
There is a large version of this layout in Appendix VI of the DMX-40 Reference
Manual you can use print out and as a guide. For now, just note the following keys:
a. the 4-way Receiver Frequency Control keys (bottom right)
b. the Gain Control keys, (to the left of the frequency controls)
c. the Restart Decoder (space bar) key.
Note that the initial frequency display shows 7.030000, which is 7.03 MHz, and the
initial frequency step size of 1 Hz. 7.03 MHz is the small signal calling frequency for 40
meters.
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