1. Overview of features
This 5W CW transceiver kit includes a large number of features defined by the firmware in the
ATmega328P microcontroller chip. The following is a brief summary of the features to explore and
enjoy. Read the subsequent sections for more detailed information on these features.
Synthesised VFO with rotary encoder tuning
The VFO is an Si5351A Synthesiser chip, configured by the microcontroller. A rotary encoder
tunes the VFO, with a variable tuning rate. The radio includes two VFOs, A and B. You can swap
from one to the other, copy the contents of the active VFO to the inactive one, or operate Split
(Transmit on VFO A, receive on VFO B). There is also a RIT mode offering a receive offset of up
to +/- 9,999Hz. The CW offset is also adjustable, and CW-R (sideband swap) mode is supported.
Memory features
There are 16 frequency presets for your favourite operating frequencies. Each frequency preset
can be edited in the configuration menu, or loaded/saved into/from the currently operating VFO.
Message mode
The firmware supports storage of 12 messages. Four of these are 100 characters long, the other
eight are 50 characters long. A single button click shows the list of messages to send. Message
sending can be configured to send just once, or a configurable number of times, or indefinitely
repeating. The interval between transmissions is also configurable. The message feature can be
useful, for example, for setting up a repeated CQ call with a pause between repeats, during which
you can listen for any answers. As soon as you touch the key the message sending is canceled.
When message sending is in progress an ‘M’ character appears near the top right of the display.
CW Keyer
Operation with a Straight key is possible, but the firmware also includes an Iambic keyer, for
connection of a paddle. The keyer can be configured to operate in Iambic modes A or B, or
Ultimatic mode. The keyer speed is variable both from the configuration menu and via a single
button press during operation.
With its solid-state, microcontroller operated transmit/receive switch, the radio can operate in full
break-in “QSK” mode, or if you prefer, semi-break in.
CW Decoder
A CW decoder operates in the chip. This can be useful on air, particularly for newcomers to CW,
though it is never anywhere near as good in QRM or weak signal conditions as a good CW
operator using the wet-ware between his ears. The decoder has a “Practice” mode too, for you to
practice your CW sending without actually generating RF. The decoder can also be used to
conveniently enter text in the message storage, or for configuration of any of the other menu
items. The decoder can also be switched off if desired.
CW, FSKCW or WSPR Beacon mode
A beacon is included too, and this can be configured to operate in CW, FSKCW or WSPR mode.
Owners of the QRP Labs Ultimate-series weak signal mode transmitter kits will be familiar with the
operation of WSPR. A GPS module such as the QRP Labs QLG1 GPS receiver kit can optionally
be connected to this CW transceiver kit to provide frequency and time discipline, as well as setting
the Maidenhead locator (from latitude and longitude) that is encoded in the WSPR message.
QCX operating manual, firmware 1.07, manual edit 0.03
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