Tag Archives: QRP

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 :


73 TU ee



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!

Frank builds the EA3GCY DB4020 Dual-band 40 and 20M QRP SSB Transceiver Kit

The following article first appeared on our sister site, the SWLing Post:

Many thanks to SWLing Post contributor, Frank (ON6UU), who shares the following guest post:

Building EA3GCY’s DB4020 QRP Transceiver kit

by Frank Lagaet (ON6UU)

In May, I discovered via a newsletter that a new kit was available from Javier EA3GCY in Spain.  I was immediately sold as this was a kit from my favourite kit producer and it has 2 bands–it will also be able to do CW and there also will be a CW filter.

After building 2 MFT’s from Javier which work without problems, I needed to have the DB4020.  The MFT’s are for 20 and 40 mtrs and do DSB (double side band).  I did put them in a not-so-graceful box but they do what they are intended for which is QRP phone (SSB).   They came together without problems so I expected the same for the DB4020–I knew for sure when I saw the board:  all through-hole components (except for some capacitors which are factory soldered) and a lot of space on the board.   The board has been silk-screened with clear indications on where all components have to come and the manual has very clear instructions where each component has to be soldered with referral to a quadrant.  The manual provides a 252 quadrant page so it is a piece of cake to find where each piece goes.

What do you get?

Javier provides you with all components which need to be installed on the board and, of course, the kit board.  The components come in small marked plastic bags and all is well-wrapped up in bubble wrap.  The board is wrapped separately and that is put together with the component wrap which is then again wrapped up in bubble plastic.  All goes into an envelope.  Very well packed I must say.

Here’s a picture of the bags with components:

The silk-screened board:

I started with the resistors since that’s the easiest way. After that, I did the capacitors.  I like to solder in all flat components first, so next were the diodes and IC sockets followed by the elco’s.  The transistors were next together with all relays.  As you solder in the transistors one also has to mount the cooling heatsinks,  these cooling sinks are high and are ideal to protect the coils one has to make,  they also protect the polystyrene caps (which I always find vulnerable) when the board is upside down.

Many kit builders are afraid of winding the toroids in kits–don’t be!  It is easy.  Just take your time and follow the instructions given by Javier in the construction manual.  In this kit the builder has to wind 8 toroids:  6 are a single wire which goes through the toroid body,  1 is a toroid with 2 different windings, and 1 has a twisted pair which goes through the final toroid.  Be sure to measure the wire you need per toroid as instructed in the manual.  Javier gives some spare, so you can be sure.  You will also see that on next picture where the legs of the toroids have not been trimmed yet.  Once done I still had some centimetres of wire leftover.

Picture of the toroids ready to be soldered in:

Finally all other parts and pin headers went in,  jumpers were immediately put on where needed.

As I’m using a military-grade plastic box, I have to break-out some components like the display,  tuning encoder,  volume and rx control from the board.  I also have put an on/off switch on the box and already have the CW KEY connector ready installed. I also installed a loudspeaker in the box.  The SI5351 board and the Ardiuno Nano are the final components which go into the board after installing all wires.

Picture of the board:

I intend to attach a CW paddle to the box made out of a relay.  A HWEF tuner (from EA3GCY) which I was planning to incorporate in the box is I think a bit overkill. That HWEF tuner is already in a nice little box and would be a pity to dismantle,  also I’m running out of space in the box…  Maybe I can fit in a 9-1unun which would then give me good results on both bands…?

Maybe I will install a battery pack in the same box.

The box with board installed:

The box completed front side:

Mind you,  it still needs some additional switches for the CW part of the transceiver.

Frank (ON6UU)


Brilliant, Frank! I really appreciate the video as well–sounds like the kit produces smooth audio and should serve you well. No doubt, that military box enclosure will survive even the roughest field conditions!

Click here to check out the DB4020 kit at EA3GCY’s store.

2019 Homebrew Heros Award Winner

Many thanks to Pete Eaton who notes that Hans Summers has won the 2019 Homebrew Heroes award. Congratulations, Hans!

Click here to view on YouTube.

The CommRadio CTX-10 has landed

[Note: This is a cross post from my other radio blog, the SWLing Post.]

Yesterday, UPS delivered a much-anticipated package: the CTX-10 QRP transceiver from CommRadio.

CommRadio dispatched this loaner CTX-10 for evaluation and I’m excited to get my hands on it since it’s not everyday I get to evaluate a transceiver designed around field portability (my favorite category of gear).

Yesterday, I took a few shots of the CTX-10 as I unpacked it:

I’ll need to build a fused power cable with the supplied pigtail and also sort out an 8 conductor (Yaesu compatible) modular plug microphone. Of course, I’ll give this radio a thorough review testing it on SSB, CW and digital modes (especially FT8).

Since the CTX-10 is built on the CommRadio CR-1 and CR-1A I anticipate a capable receiver section (in other words, expectations are high). Of course, I’ll test the CTX-10’s ability as a broadcast receiver as well.

Follow my progress by following the tag: CTX-10

The Elecraft KX3 still impresses

Note: this post was originally publish on my other radio blog, The SWLing Post.

I’ve owned my Elecraft KX3 for five years, and this little rig continues to amaze me.

In 2013, I gave the KX3 one of the most favorable reviews I’ve ever published–and it continues to hold its own. That’s why last year I recommended the KX3 to my buddy and newly minted ham radio operator, Sébastien (VA2SLW), who had already been eyeing the KX3 as his first HF transceiver.

A few weeks ago, Sébastien bit the bullet and is now the proud owner of a KX3 with built-in ATU. He purchased the KX3 with plans to do a lot of field operations including SOTA (Summits On The Air) and also use the KX3 at home.

Wednesday, I popped by Sébastien’s flat to help sort through some low-profile antenna options. I had suggested that he not invest in a factory made antenna just yet, but instead explore what he’s able to do with a simple wire antenna directly connected to the KX3 with a BNC Male to Stackable Binding Posts adapter. I’ve had excellent luck using this simple arrangement this in the past with the KX3, KX2 and even the KX1.

I did a quick QRM/RFI survey of his flat and balcony with my CC Skywave SSB. While there were the typical radio noises indoors, his balcony was pleasantly RFI quiet. At 14:00 local, I was able to receive the Voice of Greece (9,420 kHz), Radio Guinée (9,650 kHz) and WWV (both 10,000 and 15,000 kHz) with little difficulty. His building has incredibly thick concrete walls–I assume this does a fine job of keeping the RFI indoors. Lucky guy!

We popped by a wonderfully-stocked electronics shop in Québec City (Électromike–which I highly recommend) picked up some banana plugs and about 100′ of jacketed wire. We took these items back to the flat and cut a 35′ length of wire for the radiator and about 28′ for the ground. We added the banana plugs to the ends of each wire.

Sébastien temporarily attached one end of the antenna wire to the top of the fire escape and we simply deployed the ground wire off the side of the balcony. Neither of these wires interfere with his neighbors and neither are close to electric lines.

I had planned to cut both the radiator and ground until we found the “sweet spot”: where the ATU could find matches on 40, 30, 20 and 17 meters (at least).

Much to my amazement, the KX3 ATU got 1:1 matches on all of those bands save 80M where it still could achieve a 2.8:1 ratio.  I couldn’t believe it!

Frankly, Elecraft ATUs are nothing short of amazing.

Even the ATU in my little KX2 once tuned a 20 meter hex beam to 40 meters and found a 1:1 match to boot. In contrast, the Icom IC-7300 sitting next to the KX2 wasn’t able to match that hex beam even though we performed a persistent ATU search. Not surprising as I wouldn’t expect a 40 meter match on a 20 meter antenna, but the Elecraft ATU did it with relative ease.

Sébastian did a quick scan of the ham radio bands where we heard a number of EU stations. I also took the opportunity to point out how well the KX3 operates as a broadcast receiver with the AM filter wide open and using headphones in the “delay” audio effects mode. The Voice of Greece sounded like a local station–absolutely gorgeous signal.

It was getting late in the day, so I couldn’t hang around to call CQ with Séb, but I left knowing that he is going to have a blast playing radio at home and, especially, in the field. Next, he plans to build a simple mag loop antenna, get a BioEnno LiFePo battery and eventually add other Elecraft accessories to his station. I’d say he’s off to a great start!

Want more info? Click here to read my review of the Elecraft KX3 and here to read my review of the Elecraft KX2.

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The uBITX Transceiver: Pricing and more details

Many thanks to Pete Eaton (WB9FLW) who shares pricing and additional information about the uBITX general coverage QRP transceiver:

Here are the details, if purchased before Christmas $109 delivered!


From uBITX creator, Ashhar Farhan:

1. The ubitx is now available for sale, for $109 dollars (includes the shipping), but only until Christmas. *After Christmas, the price will increase to $129 dollars. for this initial batch, a few ham volunteers and I pitched in to sort the crystals, test the coils, tune-up and box these initial kits, we won’t be able to do that any more. we will have to hire more people (which is not a bad thing) and get them to do it.

2. The ubitx is on sale at hfsignals.com, not hfsigs.com. it is easier to remember. we will soon point hfsigs.com to the new website as well. The new site is in wordpress, that means that we can have volunteers writing and updating it rather than waiting for me to hand code the content in html and vi editor.

3. We need help with proof reading the web content.* If you find any typos, please mail me on [email protected] address (not the bitx20 list),

These apart, the early buyers must be aware that they are beta users of sorts, the firmware will sure get updated. i hope there won’t be any revisions of the PCB.

Pete adds:

Just as an aside the original price of the Heathkit HW-8 was $139.95 (in 1970 dollars) and it became a QRP Classic. The uBITX may become  one as well and like the HW-8 there will be (and already are) all sorts of mods/additions one will be able to do. The uBITX is 10 dollars cheaper (after 12/25) works 80-10 M, does SSB in addition to CW, and is a Superhet to boot!

Farhan your hit this one out of the Ballpark!

Very cool, Pete!  I am very tempted to purchase the uBITX transceiver before Christmas and have it delivered via DHL service.  The only thing holding me back is simply the amount of projects I have on my table at the moment! $109 is an incredibly low price for a full-fledged QRP transceiver!

I’m absolutely amazed that it is also has a general coverage receiver.  Perhaps the uBITX could serve the SWL as well as the ham radio operator?  I suppose we shall soon find out!

Click here to read our other posts regarding the uBITX transceiver.

Click here to order the uBITX transceiver kit.

Please comment if you plan to or have purchased the uBITX. We’d love your feedback!

The uBITX Transceiver: An Update

Many thanks to Pete Eaton (WB9FLW) who shares the following post:

Last March Ashhar Farhan VU2ESE the designer of the very popular BITX20 and BITX40 series of mono-band HF Transceivers announced a new low cost Rig called the uBITX (micro BITX) a full blown 80-10m 10 Watt SSB/CW Transceiver. Now comes word that after many months of very hard development work by Ashhar this much anticipated Rig will soon be available.

For those not familiar with the Project this is *not* a kit, rather like its sibling (the BITX40) it consists of two assembled and tested Circuit Boards. The RF board measures 5.5 x 6 inches and a second small plug in daughter card that takes care of the digital portion of the design including the 2X16 LCD, Arduino Nano, and Si5351 which are used in the VFO. Add a Cabinet, Knobs, and Connectors and you have a full blown HF Rig. An added plus is that except for the Gerber PCB files everything else (including the firmware) is Open Sourced!

The original description can be found here:


Farhan has just released the Firmware, Schematics, and Wiring Diagram for the production version on GitHub

Arduino Sketch:


RF Board Schematic:


Digital (Raduino) Board Schematic:


Wiring Diagram:


Farhan has a social conscience as well giving several local Ladies much needed employment for final assembly and checkout of the Rigs.

There are still a few final tweaks being done to the design so pricing is still to be determined. But if it’s offered at a similar price point as his earlier Transceivers it should sell like Hotcakes!

For the latest info check out the BITX User Group at:


Wow!  Amazing project!  Thanks for the tip and updates, Pete!

QRP Activities at Shelby Hamfest

Many thanks to Bill (W4SFV) who shares the following announcement:

QRP advocate Bill Minikiewicz, of Breadboard Radio, will present a talk on QRP at this years Shelby Hamfest. Although the presentation will focus on the why and how of QRP operation designed to get hams excited about low power operating there will also be time for discussion about your experiences as QRPer’s.

Hopefully, this will turn into an annual QRP get together for the Southeast QRP gang. Several Breadboard Radio Kits will be given away, so be sure to attend. Also look for W4FSV operating QRP pedestrian in the Tail Gate area!

The Shelby Hamfest will be September 1, 2 and 3, 2017 at the Cleveland County Fairground, Shelby, NC. Bill’s talk is at 12 noon. Check out www.shelbyhamfest.com.

Excellent, Bill! Though I’m hosting a table in the flea market at Shelby this year, I will certainly plan to attend your QRP session!

micro-BITX: a homebrew general coverage SSB/CW QRP transceiver

Image Source: uBITX)

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

Farhan VU2ESE Does It Again!


A compact 10 watts, easy to build, general coverage SSB/CW transceiver for HF bands

Homebrewers have traditionally avoided making multiband transceivers as they can get extremely complex and difficult to make. There have been some remarkable successes in the past, the CDG2000 (designed by Colin Horrabin G3SBI, Dave Roberts G8KBB and George Fare G3OGQ)is one such design. The SDR route as followed by several designs offer some simplification at the cost of bringing digital signal processing and a PC into the signal path.

On the other hand, many of the homebrewers do need a general coverage transceiver on the bench as well as as a base transceiver for bands beyond the HF. I ended up buying an FT-817ND that has been a reliable old warhorse for years. Two years ago, I attempted a high performance, multi-band architecture with the Minima transceiver. The KISS mixer of the Minima, though a very respectable receiver front-end, had serious leakage of the local oscillator that led that design to be abandoned as a full transceiver. Over months, I have realized that the need for a general coverage HF transceiver was wide-spread among the homebrewers. Most of us end up buying one.

While achieving a competition grade performance from a multiband homebrew is a complex task as evidenced by the works like that of HBR2000 by VE7CA, it is not at all difficult to achieve a more modest design goal with far lesser complexity. The uBITX shoots to fulfill such a need. It is a compact, single board design that covers the entire HF range with a few minor trade-offs. This rig has been in regular use on forty and twenty meters for a few months at VU2ESE. It satisfies for regular work, a few trips to the field as well.

A key challenge for multiband transceivers has been to realize a local oscillator system with such wide range. Silicon Labs has now produced a series of well performing oscillators that solve this challenge trivially : You connect the oscillator chip over a pair of I2C lines and it is done. The Si5351a is one such a part that provides 3 programmable oscillator outputs in a small 10 pin TSSOP package. We will exploit this chip to build the multiband transceiver.

Having exclusively used homebrew transceivers all the time, I get very confused whenever I need to use a commercial radio. There are too many switches, modes and knobs to twirl around. The uBITX use an Arduino to simplify the front panel while retaining all the functionality in a simple menu system that works with the tuning knob and a single ‘function’ button. The rig supports two VFOs, RIT, calibration, CW semi break-in, meter indicator, etc. In future, more software can be added to implement keyer, SWR display, etc.

Click here to read the full description of this project and download diagrams/schematics!

This is brilliant!  Thank you for sharing, Pete!

Ham takes SOTA activation to new level

(Source: Southgate ARC)

Amateur takes unusual route to SOTA

Colin Evans, M1BUU, from near Haworth, West Yorkshire attained SOTA Mountain Goat on Saturday 28th January on the summit of Whernside, G/NP-004.

Colin took rather an unusual approach to his activation of Yorkshire’s highest mountain, by constructing his equipment whilst on the summit.

Colin had taken a QRPme 20m RockMite kit, a home made key kit, a home made vertical antenna kit and a gas powered soldering iron along with him. Sheltering from the wind, rain and snow in a small tent, Colin successfully constructed the RockMite, key and antenna in just under 4 hours.

The first QSO for Colin with his 250mW RockMite was with N1EU near Albany, New York, over 3000 miles away, the three subsequent QSO’s were with European stations, satisfying the SOTA rule requirement of four QSO’s to claim the activation points.

SOTA Mountain Goat is awarded for gaining 1000 SOTA Activator points. For more information, visit www.sota.org.uk