Tag Archives: Kits

An Introduction to the uSDX transceiver kit

Many thanks to Pete (WB9FLW) who shares the following article by Bob (KD8CGH) regarding the uSDX transceiver kit.

I reached out to Bob who has kindly given me permission to share his article on QRPer:


An Introduction to the uSDX

by Bob Benedict (KD8CGH)

There is a new open source, home brew multi band, multi mode QRP transceiver that grew out of the QRP Labs QCX. Through some serious wizardry  it retains an efficient class E RF amplifier for SSB and digital modes. It crams impressive SDR capabilities into an Arduino.

This has an interesting international development process conducted on  https://groups.io/g/ucx/topics with contributions by many, including the usual gang of suspects: Hans Summers G0UPL, Guido Ten Dolle PE1NN, Barbaros Asuroglu WB2CBA , Manuel Klaerig DL2MAN, Kees Talen K5BCQ, Allison Parent KB1GMX, Jean-Marie T’Jaeckx ON7EN, Ashhar Farhan VU2ESE,  and Miguel Angelo Bartie PY2OHH. I apologize to the many others whose names I didn’t list. A summary is in the WIKI https://groups.io/g/ucx/wiki.

The basic work uSDX appears to have been accomplished by Guido Ten Dolle PE1NNZ. It uses pulse width modulation of the PA supply voltage to transmit  modes other than CW while retaining class E efficiency and uses a direct conversion SDR receiver.

The basic idea behind Class E nonlinear amplifiers is that transistors have little loss when they are switched fully on or off. The losses occur when devices are limiting power flow in linear amplifiers. The idea behind a Class E amplifier is to use transistors in a switching mode to generate a square wave to drive a resonant circuit to generate RF power.

This method is used in the popular QCX QRP CW transceiver kit line developed by Hans Summers and sold through QRP Labs  https://qrp-labs.com/.  More than 10,000 of these great transceiver kits have been sold (I built one). There is a good discussion of the circuit and particularly of the class E amplifier in the excellent QCX documentation https://www.qrp-labs.com/images/qcx/assembly_A4-Rev-5e.pdf.

The QCX was the base for the QCX-SSB which starts with a QCX and modified the circuit and software to add SSB capabilities. The wizardry that  Guido accomplished uses pulse width modulation of the PA supply voltage to control the amplifier in an Envelope Elimination and Restoration (EER) technique  https://core.ac.uk/download/pdf/148657773.pdf. To generate SSB a DSP algorithm samples the  audio input and performs a Hilbert transformation to determine the phase and amplitude of the complex signal.  The phase changes are transformed into temporary frequency changes which are sent  to the  clock generator. This result in phase changes on the SSB carrier signal and delivers a SSB-signal with the opposite side-band components is attenuated.

On the receive side a direct conversion SDR receiver is used with the I and Q signal digitized and all further processing carrying out digitally. Attenuators are included to help not overload the ADC range.  Documentation is at  https://github.com/threeme3/QCX-SSB .  In addition to a good description of the theory and hardware mod there is also a good description of the software command menu.

From there development took off in several directions. One is by Barbaros Asuroglu WB2CBA  and Antrak that uses through hole components (mostly) and replaceable band boards that  hold the low pass filter and band dependent class E amplifier components (an inductor and capacitor). Barb also includes boards designed to be a case top and bottom, battery pack and a PA.

Another development track by Manuel Klaerig DL2MAN uses SMT components in a stacked board layout and has a relay switched band pass board https://groups.io/g/ucx/message/1596  and  https://groups.io/g/ucx/files/DL2MAN uSDX-Sandwich Files. A new revision has been released that uses serial resonance class E amp design and easier to obtain relays, https://groups.io/g/ucx/files/DL2MAN uSDX-Sandwich Files with new Serial Resonance Class E Multiband Circuit .

Other development streams include one by Kees Talen K5BCQ https://groups.io/g/ucx/files/K5BCQ uSDX Board Schematics and Jean-Marie T’Jaeckx ON7EN https://groups.io/g/ucx/files/QCXV4.zip.

I built the variant designed by Barbaros Asuroglu WB2CBA   and I’m pleased with it’s performance. I ordered 10 main boards and 40 LP filter band boards PCBs from PCBWAY, but now you can also purchase single boards sets from https://shop.offline.systems/.

I also designed and 3D printed a case for the transceiver and a small box to carry band boards. Info at https://www.thingiverse.com/thing:4582865 and at https://www.thingiverse.com/thing:4587868 and also in the files section https://groups.io/g/ucx/files/3D printed case for Barb WB2CBA V1.02.

In an example of hams collaborating at its finest, Hans Summers  announced on 9/11/2020 that his new QCX mini product, a QCX in a smaller package,  will include a daughter board that can be used to give the QCX mini a uSDX like SSB capability. The QCX mini has the same circuit as the QCX but uses SMD components packaged it into a two board stack that is less than half the volume of the original QCX. The mod is unsupported by QRP-LABS but may be supported by the uSDX group.

http://qrp-labs.com/qcxmini.html 

More information at https://groups.io/g/ucx/topics and don’t forget the WIKI https://groups.io/g/ucx/wiki.

73

Bob,  KD8CGH


Many thanks again, Bob, for sharing this excellent uSDX introduction. Thanks again for the tip, Pete!

Pete also notes that there is a very active uSDX experimenters discussion group on Groups.io with over 100 members: https://groups.io/g/ucx

The new Inkits Easy Bitx SSB TCVR kit

Many thanks to Robert Gulley (K4PKM) who shares the following news from Inkits:

This is to inform all our valued subscribers that we have launched the much awaited easy bitx kit and few customers have already bought the kit.

The easy bitx kit works on a single band and can be built
for 20mt 40mt or 80mt bands.

This is an enhanced bitx design from the previous versions.
There is a complete manual available with link below.

Easy Bitx Version 1

Complete details are provided in the construction manual to build the kit in 15 Steps.

There are 15 individual kits packets provided to assemble the kit step by step.

The si5351 BFO VFO is provided with the kit in working condition. Only The IF frequency has to be set as described in the manual.

The easy bitx kit is an excellent educational kit for new Hams
who are wish to learn how to build a single band transceiver.
And later use it on the air.

The bitx in various kits and individual mods has been build by thousands of hams world wide, so this way easy bitx is a perfect kit for newbies.

The complete kit can be purchased from our website.

Presently we are shipping world wide with DHL Express.

Adding CW mode to the EA3GCY DB4020 Dual-band 40 and 20M QRP Transceiver Kit (Part 2)

Many thanks to SWLing Post contributor, Frank (ON6UU), who shares the following guest post which expands upon his previous DB4020 article:


The EA3GCY DB4020 transceiver now has CW mode

by Frank Lagaet (ON6UU)

After telling you all about the DB4020 SSB build I’m here with the CW part of the kit,  let’s say this is part 2.  At a certain moment Javier let me know the CW interface kit was ready for shipment and some week later it was delivered to my QTH.

Again, a well packed kit arrived in a brown envelope, components and boards well packed in bubblewrap.  I found even a board I did not expect which can hold a push button,  a switch and the connector for your morse key.  Javier thinks of everything it seems!

Unpacking the bubblewrap gave me this result,  all components in 2 bags.  In the bigger bag another 2 bags with 2 printboards,  one for the CW interface,  one for the CW filter.  Great !!  Checking the material bill resulted in all components there,  another thumbs up.

I started, of course, immediately building it because I wanted CW in the transceiver as soon as possible.  I don’t do much in SSB mode anymore and I already started missing CW on the DB4020,  so I started my KX3 to listen to while I was populating the boards.  I never thought CW was going to have this impact on me! …. ..

I started building the CW interface,  again starting with all small items.  I soon saw that the 2 relays which need to be soldered in were ideal to protect all components when the board is upside down, so I soldered them in very quickly.  I then soldered in all other components ending with the elco’s.

Next phase was the CW filter.  This board is small and came together in a blink of an eye, no problems there, the long legs of the 3 and 4 pin headers went in last.

The following day, I made all wire connections and soldered a 13pin connector,  leaving one pin out since I want to have the option to choose the width of the CW signal I’m listening to.  By cutting the FL CW + pin and adding an additional switch, I have now 500Hz or 2400Hz.  Great option, for very little effort and simple.  Another thumbs up here.

Now it was simply a matter of inserting the sub boards in the main board and all should be working.  And it did!  Hurray!  The 500Hz filter works perfectly,  filtering away all above or below stations nearby my operating frequency.

This is the result of the soldering work,  2 small boards which need to be inserted in the main board:

The CW interface still needs the 13pin header of which I cut one pin and mounted a switch to have the 2400Hz width.

The IC you see in the middle of the CW interface is the KB2 keyer which gives you several functions like 4 memories and beacon mode.  The 4 potmeters are used to set the level on 40 and 20 meters,  to set the delay between TX and RX switchover and to set side tone monitor level.   The keyer also provides functions as keyer mode A or B,  straight key function and can be set for speeds between 1 and 50WPM.   WPM speed can be set in 2 different ways.  Handy!

Here a picture of the CW filter inserted on the main DB4020 board.

The CW interface is inserted at the side of the main board,  notice the 2 wires which go to the switch to allow switch-over between 500 and 2400Hz.

(Wiring still needs to be cleaned up in this picture.)

Finally, the result:  a good working multimode QRP transceiver with 2 bands.  It should be possible to make close to medium range with it as well as DX,  even with QRP power.

And while I was building I also made a new key for this radio,  it is made out of a relay and cost nearly nothing,  looks good doesn’t it ?  hihi.

Homebrew key

The key, when in practiced hands (fingers hi), can do 50 WPM without a problem. My friend HA3HK does without blinking an eye at 40WPM with this kind of key and tells me that he can go faster if needed.  Me? I’m going it a bit slower.

Battery pack

As this radio is only using little power (0.4A in RX,  1 to 2A in TX depending the power you set it) I thought,  let’s make a battery pack for the radio.

The first plan was installing it in the box.  I did not do that because the batterypack is also powerful enough to feed my KX2 and other QRP transceivers. Since I can use it with all of them, a loose battery works out better for me.

I started with an old laptop which had a broken screen and some other malfunctions,  but still had a good battery,  although I needed the battery connector of course.  A piece of wood to mount the connector on was my next goal.  And since I still have another laptop using the same batteries, I can charge the battery without problems.  Simple, but good and it weighs much less than a gel cell battery.

The battery provides me with 12.5V and some 5Ah.  Enough to last for hours on RX and for sure good enough to activate 2 SOTA sites in one day.   It doesn’t look great but works great– that is what matters and to test it was more then good.  Next will be getting the battery pack in a nice box.  Better to re-use stuff than throwing it away I’m thinking.

I need to do something about the cover of the OLED display,  there is still some work there to make it look nicer.

Some video can be seen on YouTube :

Finallym I’d like to thank you all for reading my articles about the DB4020. I had big fun soldering, tinkering with the box, making the key, and batteryholder/batterypack.  My Hungarian friend HA3HK told me it looks a bit like a spy radio. …. ..

I also include one more time the link where you’ll find this kit :

https://www.qrphamradiokits.com/

73 TU ee

Frank

ON6UU


Thank you so much, Frank. No doubt, you had a lot of fun putting this excellent little kit together.

Implementing a filter switch was a fantastic idea and, obviously, not terribly difficult to do.

Based on the videos, the DB4020 has a low noise floor and very good receiver characteristics. I’m impressed that the CW portion of the radios has so many features as well, such as a memory keyer and beacon mode.

I also love how you reused that 5Ah laptop battery! I think that could almost give you a full day of SOTA activations at those consumption levels!

Thanks again for sharing this with us, Frank! We look forward to your future articles!

Dave Benson’s new Phaser Digital Mode Transceiver kit

Many thanks to QRPer, Pete (WB9FLW), who writes:

Just in time for Christmas, Dave Benson is back with a great new line of Monoband Digital Mode Transceivers! 40 & 80 Meters is available now 30 & 20 Meter Rigs to follow shortly.

Time for me to contact Santa Claus and update my Christmas Wish List 🙂

These are Single Signal Phasing Rigs not DSB.

Pete WB9FLW,

http://www.midnightdesignsolutions.com/phaser/

http://www.midnightdesignsolutions.com/phaser/Phaser-40%20Instructions%20(Rev%20A).pdf

WOW! Thanks for the tip, Pete! I think I might give Santa a hint! This looks like a fun kit!

FT8 transceiver kit: CR Kits taking orders

The CR Kits DSB Transceiver prototype (Source: CR Kits)

Many thanks to Pete (WB9FLW) who writes:

Thomas,
Adam of CR Kits is now taking orders for his FT8 Transceiver Kit and the price is very reasonable.

From Adam at CR Kits:

FT8 transceiver kit

Folks,
I start to take email order now. The introductory price is 39 USD for kit including shipping to worldwide. As in the introductory period, you will get audio cable options for free. The earliest possible shipment date is now improved to May 13.

You can directly PayPal to rongxh@gmail.com and let me know 40m or 20m (80m not ready yet). I will ship based on the sequence of receiving your payment. I may delay shipment for one week or two due to workload.

This is the spec so far:

Summary: Crystal controlled single frequency DSB transceiver for 20m (14.074MHz), 40m (7.074MHz) or 80m (3.573MHz), other frequencies could be added per requestPower supply: 10-14V DC regulated power supply or battery pack, 12V is recommended, center positive, reverse polarity protection availableCurrent consumption in RX: about 15mA at 12VCurrent consumption in TX: about 300mA at 12VRF output: about 1W for 40m band at 12V, and a bit less for 20m bandSpurious suppression: no worse than -50dBcAntenna connector: BNC connector, 50 ohmAudio in connector: 3.5mm mono, at least 600mV to activate VOX, connects to headphone connector at PC sound card, no dedicated PTT connector is requiredAudio out connector: 3.5mm mono, connects to microphone connector at PC sound cardAmber LED: TX statusGreen LED: RX statusFrequency accuracy: -600 Hz ~ + 200 HzFrequency stability: Okay for FT8 mode per test. If the optional heater resistor R20* is added, after warm up, long term frequency stability in 10 min will be improved at the cost of acceptable short term frequency stability sacrifice in 30 sec.
Thanks, Adam

Click here to check out the FT8 DSB Transceiver via CR Kits.

N6QW introduces the Sudden QRP SSB Transceiver

Many thanks to Pete Eaton (WB9FLW) who writes:

From the fertile mind of QRP Hall Of Fame Pete N6QW comes a new Radio Project, the Sudden QRP SSB Transceiver. If you have never Scratch Built such a Rig and would like to N6QW’s latest offering deserves close inspection.

Using only readily available (and cheap) components (and few of them) one can build a Full Blown SSB Transceiver for either 40 or 20 meters. The Radio’s Design will be featured in 2 installments of GQRP’s Sprat Magazine. The 1st being in the Fall issue (Receiver/LO) and the second part with come in the Spring 2019 issue (Transmitter).

http://n6qw.blogspot.com/2018/09/2018-year-of-ssb-transceivers_14.html

Pete is also providing extensive documentation on his Website:

http://www.n6qw.com/Sudden.html

One use for the Rig is on the Digital Modes, to that end he has design a simple Digital Adapter (which is also described on n6qw.com). One possibility is for a dedicated FT8 Transceiver!

Even if you do not intend to build the Rig take a moment to check out his Web Page. There you will find a wealth of information on designing and building such Transceivers.

Pete WB9FLW

(not to be confused with Pete N6QW 🙂

Thanks for the tip, Pete! How exciting! This looks like an innovative little rig and I love the concept of only using accessible components–in the end, that will give this little rig some longevity.

QRP Labs Announces The QSX Transceiver

The QSX Transceiver

Many thanks to Pete Eaton (WB9FLW) who writes:

QRP Labs has just announced the QSX an All-Band All-Mode Transceiver Kit that should be available later this year. The Target price for the 10 Band Model is $150, also available will be a 40 Meter version for $75.00.

Details from QRP Labs:

QSX (QRP Labs SSB Xcvr) is a 40m SSB transceiver with 10-band (160m-10m) and enclosure options. The kit inherits all the functionality of the famous QCX single-band CW transceiver kit but adds SSB, AM, FM, PSK31 and RTTY. This will be the lowest cost all-HF radio available but also high performance and packed with features. These are the planned features of QSX:

  • Software Defined Radio (SDR) technology with standalone Digital Signal Processing (DSP), no PC required
  • Very high performance 24-bit Analog to Digital Converter (ADC) and 24-bit Digital to Analog Converter (DAC)
  • 40m (single band) or 160-10m (10-band, including 60m) versions available
  • Modes: SSB, CW, AM, FM, PSK31, RTTY, WSPR beacon
  • Power output: 10W from 13.8V supply (power output is adjustable by the firmware)
  • Single power supply needed, 12V to 14V
  • USB host interface and connector, for USB keyboard to allow PC-less operation on PSK31 and RTTY
  • USB device interface and connector, for PC CAT Control
  • QSX can appear to a PC as a high performance 24-bit USB sound card and radio – for digital modes from a PC e.g. FT8, either demodulated or as I-Q for PC SDR programs
  • Built-in CW IAMBIC keyer (or straight keying also possible) with raised-cosine key-envelope shaping
  • DSP features (selectable sharp filters, AGC, Speech Compression, Noise Reduction etc.)
  • Dual microphone inputs (mobile phone headset with VOX, or RJ45 connector for Kenwood/Yaesu mics)
  • Dual VFO (A/B/Split), frequency and message memories
  • Through-hole assembly only
  • Built-in test equipment features for alignment, debugging and general purpose use
  • Detailed assembly manual
  • Macro facility for user defined sequences of operations, or redefinition of controls
  • Front panel: 16 x 2 LCD (yellow/green backlight), 2 rotary encoders, 4 buttons, mic/earphones socket
  • Soft-power on/off switch, the radio saves its state automatically on switch off, so that it starts up in the same state next time
  • Free firmware updates for life, very simple firmware update procedure via a USB memory stic

QSX is still in development! The above list is subject to change. The following is a FAQ with information about QSX.

More Info on QRP Labs Web Page:

https://www.qrp-labs.com/qsx.html

Check out the following video from YOTA 2018:

Click here to view on YouTube.

Fantastic! Many thanks for sharing this, Pete! This looks like a brilliant little kit for any skill level of patient kit builder.

Black Cat Systems’ 22 Meter Band Part 15 CW Beacon Kit

Many thanks to Robert Gulley (AK3Q) who notes that Black Cat Systems has developed a simple 22 meter beacon kit. The price is $20 shipped! A few details:

The kit includes the PCB and components, including a custom programmed microcontroller that will continuously transmit the ID / callsign of your choice, up to 8 characters, at about 13 wpm.

Small size – just 2 7/8 by 1 1/2 inches. Easy to build, just a few components, all through hole, no surface mount.

When ordering you note your callsign/ID to send and it will be pre-programmed.

Black Cat Systems has all kit details including full instructions on their website (click here to read).

If you like the idea of building a beacon, you must also check out the beacon Dave (AA7EE) built recently–a true work of art!

Videos featuring the QCX Transceiver kit

Many thanks to Pete (WB9FLW) who shares the following videos and notes:

Hans Summer G0UPL has released an excellent YouTube Video describing the QCX Transceiver Kit, its Design, and Operating Features:

Click here to view on YouTube.

[And] Roberto IZ7VHF has a much more detailed video of The QCX Transceiver.

Click here to view on YouTube.

Looks like people are catching QCX Fever! What an amazing Radio!

I agree, Pete! It’s simply amazing how self-contained this transceiver is. I like the fact that the kit is through-hole and that the board appears to be high quality. I will soon have one on order. This will be a fun winter project!  Thanks for sharing, Pete!