QDX digital transceiver

QDX digital transceiver
QDX digital transceiver

I brief description of a construction problem, symptoms and solution regarding the QDX digital transceiver from QRP Labs.

The “QCX+” (QRP Labs Xcvr +): a feature-packed, high performance, single band 5W CW transceiver kit with WSPR beacon and built-in alignment and test equipment. Available for 80, 60, 40, 30, 20 or 17m bands. Experimental use on 15, 12, 10 or 6m (lower power output and reduced sensitivity). For complete details see target=”_blank” href=”http://qrp-labs.com/qcxp” target=”_blank” rel=”noreferrer noopener”>http://qrp-labs.com/qcxp  

The Optional enclosure is black anodized extruded aluminium, very sturdy and elegant. Front panel is 106 x 55mm and the depth is 146mm. The front and rear panels are drilled and cut to match the QCX+ with laser-etched lettering. The enclosure includes four self-adhesive feet. 

Optional Dev Board kit is pictured above (diagram only, as yet) in one of the above photographs and is described further below. 

Optional 25MHz TCXO module is pictured above (diagram only, as yet). In tests, the frequency change over the range 4C to 65C was +/- 0.25 ppm (parts per million). This is a tiny 14.8 x 10.5mm PCB with TCXO, SMD all ready-assembled, which is installed onto the main QCX+ PCB in place of the 27MHz crystal and 0.1uF capacitor C2. 

target=”_blank” href=”https://qrznow.com/wp-content/uploads/2021/11/p4-1200×900-1.jpg”>

Hard-copy assembly instructions are not included in the kit. You need to download the assembly and operating instructions manual from target=”_blank” href=”http://qrp-labs.com/qcxp” target=”_blank” rel=”noreferrer noopener”>http://qrp-labs.com/qcxp 

Note: The QCX+ transceiver is always shipped with the latest firmware version available at the date of shipment. 

Note: the optional target=”_blank” href=”http://qrp-labs.com/qlg2se” target=”_blank” rel=”noreferrer noopener”>GPS receiver module kit is very useful if you wish to operate this kit as a WSPR beacon (it disciplines frequency, time, and Maidenhead Locator grid square). It is also useful for calibrating the transceiver kit, to get the synthesiser reference oscillator precisely calibrated (resulting in accurate transmit/receive frequency). 

An target=”_blank” href=”http://qrp-labs.com/50wpa” target=”_blank” rel=”noreferrer noopener”>optional 50W PA kit is available, which also has an target=”_blank” href=”http://qrp-labs.com/50wpabox” target=”_blank” rel=”noreferrer noopener”>optional enclosure. This 50W PA kit will give your QCX an extra boost for those occasions when you need a bit more power – to work a particular station for a regular sked when conditions are bad; to deal with our bad band conditions these days; to work a particular DX staiton, etc etc. The 50W PA kit includes solid state Tx/Rx switching for full break-in (QSK) operation. The kit includes heatsinks and connectors as well as the PCB and all components. See target=”_blank” href=”http://qrp-labs.com/50wpa” target=”_blank” rel=”noreferrer noopener”>http://qrp-labs.com/50wpa for more details. 

target=”_blank” href=”https://qrznow.com/wp-content/uploads/2021/11/p5-1200×900-1.jpg”>

List of features: 

  • Easy to build, two-board design, spacious 10 x 13cm board with main circuit and connectors, vertical front panel board with LCD and all-controls 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
  • On-screen real time clock (not backed up)
  • 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: 2.1mm power barrel connector, 3.5mm keyer jack, 3.5mm stereo earphone jack, 3.5mm stereo jack for PTT, 3.5mm stereo jack for CAT control,  BNC RF output
  • 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)
  • CAT control interface
  • Optional 50W PA kit
  • Optional aluminium extruded cut/drilled/laser-etched black anodized enclosure

Optional Dev Board kit

The development board kit is for anyone who wishes to experiment or modify their QCX+. The development board kit consists of a kit of parts including a PCB with the following features:

  1. High quality, double-sided PCB sized 95mm x 120mm (see PCB CAD exported diagram in the photos above)
  2. Through-hole plated holes with solder pads on top and bottom sides, on a standard 0.1-inch (2.54mm) matrix
  3. Ring of holes around the outside edge are all connected to ground
  4. Holes in the PCB are drilled to allow a screwdriver adjustment of the C1 trimmer capacitor, and the three trimmer potentiometers
  5. holes for fitting pin header connectors that mate with connectors on the main QCX+ PCB, for:
    a) Power (Gnd, +5V, 12V)
    b) Si5351A Clk0/1/2 outputs)
    c) I2C bus
    d) ISP header
    e) Frequency counter, DVM and RF Power inputs
    f) I and Q outputs (IC5 pin 1 and 7)
    g) I and Q path phase shift outputs
    h) CW filter input and output
    i) Audio amplifier input and output
    j) GPS header
    k) CAT control and PTT signals
    l) All pins of the PTT, CAT and Audio connectors

The dev kit consists of the following items:

  • 95 x 120mm PCB
  • 4pcs 12mm nylon hex spacer for mounting the PCB above the main QCX+ board
  • 8pcs 6mm M3 nylon screw 
  • 8pcs 2-way female header connector
  • 1pcs 20-way male header connector (may be broken into smaller pieces as desired)

target=”_blank” href=”https://qrznow.com/category/review/”>Review

target=”_blank” href=”https://qrznow.com/my-wife-bought-more-radio-gear-on-wish-and-ali-express/”>My Wife Bought More Radio Gear On Wish and Ali Express

target=”_blank” href=”https://qrznow.com/my-wife-bought-more-radio-gear-on-wish-and-ali-express/”>My Wife Bought More Radio Gear On Wish and Ali Express

My wife surprised me at the end of 2020 with a new random box of goodies from Wish and AliExpress. Today we unbox some of these ODD radios and radio a… target=”_blank” href=”https://qrznow.com/my-wife-bought-more-radio-gear-on-wish-and-ali-express/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/civility-in-ham-radio-the-amateurs-code/”>Civility in Ham Radio: The Amateur’s Code

target=”_blank” href=”https://qrznow.com/civility-in-ham-radio-the-amateurs-code/”>Civility in Ham Radio: The Amateur’s Code

The Amateur’s Code was written in 1928 and very much applies today. Let’s take a look at the Code and how it can improve civility in our h… target=”_blank” href=”https://qrznow.com/civility-in-ham-radio-the-amateurs-code/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/a-day-at-mfj-how-their-products-are-made-and-how-quality-is-job/”>“A Day At MFJ.” How Their Products Are Made And How Quality Is Job

target=”_blank” href=”https://qrznow.com/a-day-at-mfj-how-their-products-are-made-and-how-quality-is-job/”>“A Day At MFJ.” How Their Products Are Made And How Quality Is Job

“A Day At MFJ.” How Their Products Are Made And How Quality Is Job target=”_blank” href=”https://qrznow.com/a-day-at-mfj-how-their-products-are-made-and-how-quality-is-job/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/haarp-2-meter-antenna-review-by-m0ogy/”>HAARP 2 Meter Antenna Review By M0OGY

target=”_blank” href=”https://qrznow.com/haarp-2-meter-antenna-review-by-m0ogy/”>HAARP 2 Meter Antenna Review By M0OGY

“Welcome to my exclusive look at the new HAARP two meter antenna designed and built in North Lincolnshire by Phil Simpson M0PXS. Whilst the name… target=”_blank” href=”https://qrznow.com/haarp-2-meter-antenna-review-by-m0ogy/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/general-amateur-radio-exam-part-13-digital-modes-pt-5-hf-antennas-part-3-ham-college-42/”>General Amateur Radio Exam part 13. Digital Modes pt 5, HF Antennas part 3 – Ham College 42

target=”_blank” href=”https://qrznow.com/general-amateur-radio-exam-part-13-digital-modes-pt-5-hf-antennas-part-3-ham-college-42/”>General Amateur Radio Exam part 13. Digital Modes pt 5, HF Antennas part 3 – Ham College 42

target=”_blank” href=”https://qrznow.com/general-amateur-radio-exam-part-13-digital-modes-pt-5-hf-antennas-part-3-ham-college-42/” class=”read-more-link”>Read more


target=”_blank” href=”https://qrznow.com/category/equipment/”>Equipment

target=”_blank” href=”https://qrznow.com/motorola-apx-next-xe-focused-in-the-extreme/”>Motorola APX NEXT XE – Focused in the Extreme

target=”_blank” href=”https://qrznow.com/motorola-apx-next-xe-focused-in-the-extreme/”>Motorola APX NEXT XE – Focused in the Extreme

Focused in the extreme. The demands of a call require you to adapt and overcome all obstacles. When your focus on the call is threatened, other lives… target=”_blank” href=”https://qrznow.com/motorola-apx-next-xe-focused-in-the-extreme/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/codan-envoy-hf-smart-radio/”>Codan Envoy HF Smart Radio

target=”_blank” href=”https://qrznow.com/codan-envoy-hf-smart-radio/”>Codan Envoy HF Smart Radio

Codan Envoy Channels and ScanningUp to 1000 simplex or semi-duplex. Up to 20 scan groups. Simultaneous scanning for Selcall (ALE/CCIR) and voice. Dwel… target=”_blank” href=”https://qrznow.com/codan-envoy-hf-smart-radio/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/new-lna-filter-for-radio-astronomy-hydrogen-line-observations-released-by-nooelec/”>NEW LNA + FILTER FOR RADIO ASTRONOMY HYDROGEN LINE OBSERVATIONS RELEASED BY NOOELEC

target=”_blank” href=”https://qrznow.com/new-lna-filter-for-radio-astronomy-hydrogen-line-observations-released-by-nooelec/”>NEW LNA + FILTER FOR RADIO ASTRONOMY HYDROGEN LINE OBSERVATIONS RELEASED BY NOOELEC

NooElec have recently released a new LNA + filter combo called the “SAWbird+ H1 Barebones” which significantly lowers the entry bar for ne… target=”_blank” href=”https://qrznow.com/new-lna-filter-for-radio-astronomy-hydrogen-line-observations-released-by-nooelec/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/lp-100a-digital-vector-wattmeter-by-n8lp/”>LP-100A Digital Vector Wattmeter by N8LP

target=”_blank” href=”https://qrznow.com/lp-100a-digital-vector-wattmeter-by-n8lp/”>LP-100A Digital Vector Wattmeter by N8LP

LP-100A Digital Vector Wattmeter Everything you need for critical station monitoring, tuning and protection on one screen. No other meter has dual bar… target=”_blank” href=”https://qrznow.com/lp-100a-digital-vector-wattmeter-by-n8lp/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/a-prototype-foot-switch-for-the-future-by-jh5ghm/”>A Prototype Foot Switch for the Future by JH5GHM

target=”_blank” href=”https://qrznow.com/a-prototype-foot-switch-for-the-future-by-jh5ghm/”>A Prototype Foot Switch for the Future by JH5GHM

Judging from CQ-Contest reflector discussions, many contesters do not seem to appreciate the importance of a foot switch in a contest environment. For… target=”_blank” href=”https://qrznow.com/a-prototype-foot-switch-for-the-future-by-jh5ghm/” class=”read-more-link”>Read more


target=”_blank” href=”https://qrznow.com/category/ham-radio-antena/”>Antenna

target=”_blank” href=”https://qrznow.com/field-day-antennas-podcast-arrl-the-doctor-is-in/”>Field Day Antennas [ PodCast ] – “ARRL The Doctor is In”

target=”_blank” href=”https://qrznow.com/field-day-antennas-podcast-arrl-the-doctor-is-in/”>Field Day Antennas [ PodCast ] – “ARRL The Doctor is In”

The Doctor offers advice about antenna options for the upcoming ARRL Field Day.  target=”_blank” href=”https://qrznow.com/field-day-antennas-podcast-arrl-the-doctor-is-in/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/mosley-pro-96-s-10-12-15-17-20-30-40-meters/”>Mosley PRO-96-S	  10, 12, 15, 17, 20, 30, 40 Meters

target=”_blank” href=”https://qrznow.com/mosley-pro-96-s-10-12-15-17-20-30-40-meters/”>Mosley PRO-96-S 10, 12, 15, 17, 20, 30, 40 Meters

Mosley PRO-96-S    10, 12, 15, 17, 20, 30, 40 Meter 4 Element on 40 3 Elements on 30 5 Elements on 12, 15, 17, 20 8 Elements on 10 No measuring, Pre-d… target=”_blank” href=”https://qrznow.com/mosley-pro-96-s-10-12-15-17-20-30-40-meters/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/another-look-at-the4-alpha-delta-dx-ee-antenna/”>Another Look at the4 Alpha-Delta DX-EE Antenna

target=”_blank” href=”https://qrznow.com/another-look-at-the4-alpha-delta-dx-ee-antenna/”>Another Look at the4 Alpha-Delta DX-EE Antenna

  target=”_blank” href=”https://qrznow.com/another-look-at-the4-alpha-delta-dx-ee-antenna/” class=”read-more-link”>Read more


target=”_blank” href=”https://qrznow.com/category/app-ham-radio/”>App – Mobile

target=”_blank” href=”https://qrznow.com/ham-radio-license-exam-preparation-for-iphone-and-ipad/”>Ham Radio License Exam Preparation for Iphone and IPad

target=”_blank” href=”https://qrznow.com/ham-radio-license-exam-preparation-for-iphone-and-ipad/”>Ham Radio License Exam Preparation for Iphone and IPad

  Get Your Ham Radio License You are only 35 questions away from getting your Ham radio license. The questions come from a pool of questions publ… target=”_blank” href=”https://qrznow.com/ham-radio-license-exam-preparation-for-iphone-and-ipad/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/free-app-allows-blind-hams-to-work-psk31/”>Free App Allows Blind Hams to Work PSK31

target=”_blank” href=”https://qrznow.com/free-app-allows-blind-hams-to-work-psk31/”>Free App Allows Blind Hams to Work PSK31

A free, new app — Accessible Digipan — has been released that allows blind hams to operate PSK31. The download includes the app, audio tutorials, deta… target=”_blank” href=”https://qrznow.com/free-app-allows-blind-hams-to-work-psk31/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/nkccluster-2-1-to-be-released-very-soon/”>NKCCluster 2.1 to be released very soon

target=”_blank” href=”https://qrznow.com/nkccluster-2-1-to-be-released-very-soon/”>NKCCluster 2.1 to be released very soon

A new NKCCluster release is just around the corner: release 2.1 is currently undergoing beta-testing and, provided no last minute surprises i.e. major… target=”_blank” href=”https://qrznow.com/nkccluster-2-1-to-be-released-very-soon/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/koch-morse-trainer-pro-android-app/”>Koch Morse Trainer Pro – Android App

target=”_blank” href=”https://qrznow.com/koch-morse-trainer-pro-android-app/”>Koch Morse Trainer Pro – Android App

  Take your morse code to the next level with Koch Morse Trainer Pro. The only trainer that supports prosigns (procedural signals) and non-english cha… target=”_blank” href=”https://qrznow.com/koch-morse-trainer-pro-android-app/” class=”read-more-link”>Read more

target=”_blank” href=”https://qrznow.com/n1kdos-lotw-look-android/”>N1KDO’s LoTW Look – Android

target=”_blank” href=”https://qrznow.com/n1kdos-lotw-look-android/”>N1KDO’s LoTW Look – Android

    This application allows Amateur Radio Operators to browse and search their Logbook of the World (LOTW) QSL confirmations on their handheld de… target=”_blank” href=”https://qrznow.com/n1kdos-lotw-look-android/” class=”read-more-link”>Read more

The post target=”_blank” href=”https://qrznow.com/qdx-digital-transceiver/”>QDX digital transceiver appeared first on target=”_blank” href=”https://qrznow.com/”>QRZ NOW – Ham Radio News.

Author: iz4wnp