Solar X - rays:
Would you like to work Oceania, pacific
or some other DX with 20W? If you do then you should start working digimodes. I
will try to explain it here in basic, so you could start working quickly.
What do you need? You need transceiver, computer (at least 486) and software for
digimodes. When you get all this, you should first connect your computer and
transceiver. Most digimode softwares are made for sound card, so your PC should
have one. There are few possibilities how to key your transceiver via sound
card. You can key it by using VOX from your transceiver, key it manually or by
using a little interface. I will explain here how to make a little interface.
It's very simple to make it. You need:
female COM PORT connector with case
MIC connector that fits your station
NPN transistor (BC107, BC109....) & resistor 10kΩ
That's all regarding hardware for your transmission. Now you need to make
another cable for receive. One end of cable connect to your external speaker or
headphones jack of your transceiver. On second end of cable you should solder
banana connector that fits to your PC sound card (line in or mic jack). When you
finish this cable, just connect PC&radio and your job with hardware is finished.
to see schematics of interface.
Now you need software to work digimodes. There's a lot of digimode softwares.
Some of them are made only for one type of digimode (i.e. Digipan (PSK), MMSSTV
(SSTV), MMTTY (RTTY), PSK deluxe,...) and some of them unite all types (PSK,
SSTV, RTTY, packet,...). Those programs are demo versions or shareware. Press
here to find links to
this programs. After downloading and installing software to your PC, you should
do the following things:
personal data, like your
call, name, QTH and if you know, your grid locator. That's important for
macros (see below), because you put CALL, NAME or QTH command instead writing
it each time.
Configure PTT or CAT control.
You must do this if you wish to transmit.
Adjust output and input volume
control. Important thing in digimodes is that you use low power, not more than
50W. Why, you will ask? Because for receiving quality signals, it's not needed
to hear it loud. The best is if your signal is between -25 and -30dB (IMD
measurement). With strong signal you will disturb and not allow others to
receive, because your signal will be wide, overridden and covering low
signals. You can increase/decrease power with output volume sliders or with
MIC gain. For the first time put your sliders a little bit below 50% (
volume&wave) and experiment with sliders and MIC gain, until you reach power
about 50W max. The best is, if you do it with dummy load, so you will
eliminate QRM and your radio will not sweat.
Do not transmit for long time while setting output volume as it may break your
radio!! The same rule is also for input
volume. It will be OK if you put sliders to minimum ( turn off MIC booster).
If nothing is received, then push slider bit by bit higher, until your
receiving of signal is readable. Remember that
you can destroy your sound card if strong signal gets into it, so watch out
what you're doing!!
Also adjust volume on
your radio, don't turn it too loud. It won't be bad if you read help file of
program you will be using.
Macros are "buttons" in which you write informations that you will transmit
(i.e. your name, QTH, grid locator, working conditions,...). They allow you to
transmit all this data with a simple mouse click or by pressing function key,
instead of typing it every time. You write data into macro when you right
click on macro, macro window opens, and then you write data. Usually you
should first put TX command, then write data and at the end put RX command.
Look well description of commands in command window as they might make it
easier for you to write macros.
Almost every digimode program has it's own log,
so you needn't to write extra log for digimode QSO's.
Now regarding frequencies for digimodes on 11m, they are not defined. Most
operators in Europe use following frequencies:
RTTY, PSK, CW (if
you are familiar with this kind of transmission,
you can work here
SSTV call and then
This would be the basic things about digimodes. For better understanding you
should carefully read help menu in your digimode software. If there are any
questions about this matter, you can write me and I'll try to answer them.
not many people working digimodes on 11m, but YOU can help us by your presence
to attract people working this kind of transmissions. Looking forward seeing
you on my screen.