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QCX: a feature-packed, high performance, single-band 5W CW transceiver kit, with WSPR beacon and built-in alignment/test equipment. Available for 80, 60, 40, 30, 20 or 17m bands. It has rotary encoder synthesised tuning, VFO A/B/Split, Iambic keyer, CW decoder, and more...

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The "QCX" is a 5W, single-band, high performance CW transceiver kit with WSPR beacon, and built-in alignment/test equipment. It is available for 80, 60, 40, 30, 20 or 17m bands. See below for the long list of features! This is a kit of parts that you assemble yourself. There are NO surface mount components to solder (two SMD ICs are already factory pre-soldered). We do not currently have any enclosure available for this kit, it may be something we investigate in the future. 

Please see QCX Frequently Asked Questions page for any queries you have. 

IMPORTANT: SLOW SHIPPING: Note, order volume of this kit was (and is) extremely high. It will take some time to ship out all the orders and the shipment office already have high order volume. Please be patient. Your CW transceiver kit(s) will be assigned a Serial Number, notified to you by email. The serial number of the next kit to be shipped is shown below and will be updated daily. You can check to see where you are in the queue. If your serial number is less than the "next to ship" below, it means the kit is already on its way to you. See the shipping statistics page to get an approximate idea of how long it will take to reach you. 

UPDATE: 31-Oct-2017: All kits are in stock, QRP Labs shipment office are processing orders as fast as they can. (Note: some higher serial numbers than shown below were already shipped while waiting for stock of 20m and 40m LPF kits). 

UPDATE: 06-Dec-2017: A block shipment of 300 QCX kits will take place over the next week. The next update will be on 13-Dec-2017, when the shipment should be done. 

Next serial number to ship:

1673

Updated 06-Dec-2017
(next update 13-Dec, see above)

  • 1 to 90, were the 90 kits for the YOTA 2017 summer cap (see below)
  • 91 was assembled by QRP Labs as a final check of the assembly instructions
  • 92 to 176 are for certain pre-orders, mostly taken at Friedrichshafen in July 2017
  • 177 to 492 general sales of the first batch, starting 21-Aug-2017 at 09:00Z
  • 493 to 987 are general sales, PRE-orders of the second batch
  • 988 (approx) and up are general sales, PRE-orders of the third batch
  • 1488 (approx) and up are general sales, PRE-orders of the 4th/5th batch (expected mid-November)

 


Assembly and operating instructions

The assembly document includes circuit diagram and a detailed description of transceiver operation. 

Assembly instructions A4 format, CLICK HERE - for world except North America (document revision 1.08, 23-Oct-2017
Assembly instructions Letter format, CLICK HERE - for North America (document revision 1.08, 23-Oct-2017)
Assembly instructions GERMAN, CLICK HERE - A4-format German translation contributed by Peter DL6DSA (THANKS!) (revision 1.08, 23-Oct-2017)
Assembly instructions JAPANESE 3-parts: part-1 part-2 part-3 translation of sections 1-4, contributed by Shig JA1XRQ (THANKS!) See Shig's website for single doc (revision 1.08, 06-Nov-2017)


Features

  • Easy to build, single-board design, 10 x 8cm, all controls are board-mounted
  • Professional quality double-sided, through-hole plated, silk-screen printed PCB
  • Choice of single band, 80, 60, 40, 30, 20 or 17m
  • Approximately 3-5W CW output (depending on supply voltage)
  • 7-16V recommended supply voltage
  • Class E power amplifier, transistors run cool… even with no heatsinks
  • 7-element Low Pass Filter ensures regulatory compliance
  • CW envelope shaping to remove key clicks
  • High performance receiver with at least 50dB of unwanted sideband cancellation
  • 200Hz CW filter with no ringing
  • Si5351A Synthesized VFO with rotary encoder tuning
  • 16 x 2 blue backlight LCD screen
  • Iambic keyer or straight key option included in the firmware
  • Simple Digital Signal Processing assisted CW decoder, displayed real-time on-screen
  • On-screen S-meter
  • Full or semi QSK operation using fast solid-state transmit/receive switching
  • Frequency presets, VFO A/B Split operation, RIT, configurable CW Offset
  • Configurable sidetone frequency and volume
  • Connectors: Power, 3.5mm keyer jack, 3.5mm stereo earphone jack, BNC RF output
  • Onboard microswitch can be used as a simple straight Morse key
  • Built-in test signal generator and alignment tools to complete simple set-up adjustments
  • Built-in test equipment: voltmeter, RF power meter, frequency counter, signal generator
  • Beacon mode, supporting automatic CW or WSPR operation
  • GPS interface for reference frequency calibration and time-keeping (for WSPR beacon)

Firmware

There have been several firmware updates since the 21-Aug-2017 launch of this QCX CW transceiver kit. These provide enhancements and bug fixes. If you have an AVR programmer you can update your firmware using the on-board programming header. The firmware version history and more information are on this page (click!)


Modifications

CLICK HERE for a Modifications page, various improvements you can easily make to your QCX radio.


Photographs

These photographs show the prototype kit, both with and without the LCD module plugged in. The powered-up kit shows the radio's Frequency Counter feature measuring the frequency generated by its Signal Generator feature.

View the embedded image gallery online at:
http://www.qrp-labs.com/qcx.html#sigFreeIde619d4bd0f


Builders' enclosure photographs

A common question about the QCX transceiver, is about what case to use for it. There is not an official QRP Labs enclosure for the QCX. But many people are finding their own solutions to this question. 

For photos and information about what some constructors have done about enclosing their QCX, visit the QCX builders' gallery page!


Videos and reviews of QCX

The kit was originally designed for the RSGB Youths On The Air summer camp buildathon in August 2017. This RSGB YOTA Vlog video, shot at QRP Labs booth at Friedrichshafen 2017. 

For more videos and reviews please see the QCX videos page!


Common Issues

The following issues have arisen more than once, and have the solutions indicated. 

Issue Solution
Microprocessor does not boot up at power-up, requires switch-off/switch-on again to power up properly See modification here
Power Amplifier instability results in low or unstable power output, or high current draw, or blown MPS2907 See modification here
LCD contrast fluctuates on transmit Check for LCD module frame short to L2, see here for details
Low output power on 20m (or other band) LPF inductance is probably too high, resulting in attenuation at the transmit frequency. Remove turns one at a time from LPF inductors L1, L2, L3
No power output at all Check continuity through L1, L2, L3 and other inductors L4 and T1, as advised in the manual. Probably one or more have not properly burnt off the enamel so there is no electrical connection. 

Performance measurements by Wd WA4MZS

Ed made some interesting measurements of his 40m QCX serial number 354 (see also builders' photos page). 

  • Power supply = 13.8 VDC
  • Current draw (receive) = 123 mA
  • Current draw (transmit) = 514 mA
  • Transmitter output (50Ω load) @ 7.020 MHz = 4.0 watts
  • Receiver MDS @ 7.020 MHz = -121 dBm (0.2 µV)
  • Reference frequency = 27.004345 MHz
  • Transmitter frequency (display 7.020 MHz) = 7.0200003 MHz
  • Transmitter 2nd harmonic (14.040 MHz) = -48.74 dBc

Spectrum analyser close-in and wide screenshots:

View the embedded image gallery online at:
http://www.qrp-labs.com/qcx.html#sigFreeId70a123d46b