QRP Labs QCX 5W CW, Руководство по сборке

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QCX assembly Rev 1.08
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4.24 Beacon menu
The beacon function is an added bonus feature of this QRP Labs CW transceiver kit! We already
have extensive experience for several years, developing the Ultimate-series QRSS/WSPR
transmitter kits (current incarnation, the Utimate3S). These have a huge array of functionality and
modes including CW, QRSS, DFCW, FSKCW, Hellscreiber (full speed and slow FSK), WSPR,
JT9, JT65, ISCAT, Opera and PI4. The vast majority of people use the Ultimate3S kit for WSPR
operation. Since it costs nothing (no extra hardware, at least) to add this functionality to the CW
transceiver, why not! Let’s do it!
The CW transceiver beacon function therefore contains a simplified WSPR implementation which
can transmit standard WSPR messages. It also has a GPS interface for discipline of time,
frequency and Maidenhead locator. The implementation of course does not have the full range of
flexibility and functionality as the Ultimate3S kit.
WARNING: WSPR transmissions operate a continuous 100% key-down duty-cycle for almost 2
minutes. You should check carefully whether the BS170’s get too hot during this period. WSPR is
much more demanding on the PA transistors than CW. If you are operating with higher output
powers (by using a relatively high power supply voltage) then you might notice the BS170s get
unreasonably hot. Even though the output stage is Class-E, nothing is 100% efficient! It will still
dissipate some power as heat. In this case you may need to fix the BS170 transistors to a small
heatsink to help dissipate the heat. The BS170 transistors Q1, Q2 and Q3 are placed at the edge
of the PCB with their flat sides facing outwards, to facilitate this
The beacon function can also operate a CW beacon.
Weak Signal Propagation Reporter
WSPR stands for Weak Signal Propagation Reporter. It is digital message format filled with clever
forward error correction. The message consists of three parts: the operator's callsign, Maidenhead
locator (4-character, e.g. IO90) and two digits specifying the power. At the receiving station,
messages are decoded and uploaded to a central internet database. At any time you can go to
WSPRnet
http://wsprnet.org and click on the map, enter your callsign (and other filters if you wish),
and see a map of where your signal is being heard.
You could also undertake more in-depth propagation studies by downloading the database of
reception reports.
The WSPR message is encoded into a set of 162 symbols, each may be 0, 1, 2 or 3, using a
compressed data format with forward error correction. The symbols are transmitted as tones, each
tone separated by 12,000 / 8,192 Hz i.e. approximately 1.46Hz. The duration of each symbol is the
reciprocal of the tone spacing, which is approximately 0.683 seconds. WSPR messages take
about 110.6 seconds to transmit, and always start at even minutes past the hour.
Due to the very narrow 6Hz bandwidth of the transmission, and the clever forward error correction,
WSPR signals can propagate globally even with a fraction of a watt.
In WSPR, timing is critical, so when using WSPR you must set the time configuration parameter
as exactly as possible. Be sure to keep the editing cursor under the rightmost (1-minute) digit of
the time parameter, watch your clock until the seconds turn over to 00, and then press the left
button. This will ensure the seconds are in sync with your real clock time. If careful attention is
given to setting the frequency and the real time clock, then successful WSPR reports will be
obtained. Of course these things are easier if you are using a GPS module: the Maidenhead